Frasnian–Famennian (Upper Devonian) conodont biofacies and Global Events in the Compte section (Central Pyrenees, Spain.)

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Héctor Barrera-Lahoz, José Ignacio Valenzuela-Ríos, Jau‑Chyn Liao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6413435/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Apr, 2026 Read the published version in Journal of Iberian Geology → Version 1 posted 5 You are reading this latest preprint version Abstract Detailed studies on conodont biofacies from upper Frasnian to middle Famennian in the Compte section (Central Pyrenees area) allow recognition of different eustatic fluctuations and the Kellwasser, Nehden and Condroz events, as well. Five conodont biofacies have been identified: Palmatolepis , Palmatolepis – Polygnathus , Polygnathus – Palmatolepis , Palmatolepis – Icriodus and the new Icriodus – Palmatolepis biofacies. The evolution of conodont biofacies during the end Frasnian reflects a sudden regressive episode at the base of FZ13b subzone and a maximum transgressive trend at the top of FZ13b subzone, which aligns with the Upper Kellwasser Event. The Kellwasser crisis reduces dramatically the conodont biodiversity, and during the lower Famennian, the conodont biodiversity recovers. A transgressive trend is recorded during the Palmatolepis crepida – Palmatolepis gl. prima zone interval, which may be referred to as the Nehden Event. Within La Mena Formation two regressive trends are identified by sharp conodont biofacies changes in the Palmatolepis rhomboidea and Palmatolepis gr. gracilis zones. These two regressive trends correspond to the lower and upper Condroz Events respectively. conodont biofacies eustatic trends Kellwasser Events Nehden Event Condroz Events Figures Figure 1 Figure 2 Figure 3 Figure 4 1 Introduction During the Upper Devonian Frasnian–Famennian transition (F/F) the conodont biodiversity experimented significant changes, including the end Frasnian mass extinction (McGhee et al., 2013 ); which was one of the big five greatest extinctions in life’s history with substantial biodiversity fluctuations (McGhee, 2013 ; McGhee et al., 2013 ). This mass extinction is recorded into two Global Bioevents named Lower and Upper Kellwasser. They are located in the uppermost Frasnian zone, FZ13, (Becker et al., 2020 ). This extinction affected the conodont diversity in different ways: Ancyrodella became extinct, Palmatolepis was reduced dramatically to one taxon ( Palmatolepis ultima ), whereas Icriodus , Polygnathus and Ancyrognathus were not widely reduced (Sandberg et al., 1988 ). The Kellwasser events are recorded worldwide on the basis of their lithological expression, which is generally documented as black shales related to anoxic phases (Becker, 1993; Walliser, 1996 ; Carmichael et al., 2019 ) and sea level changes (Sandberg et al., 1988 ; Sandberg et al., 2002 ). After the Kellwasser crisis, the conodont fauna gradually recovers the diversity through the lower Famennian. This recuperation is associated with a sea–level rise and recorded as black shale facies around Euramerica, Africa and Australia (Becker 1993a , b ; Becker and House 1997 ; Schülke and Popp 2005 ; Becker et al. 2016 ); this “faunal bloom” associated to a transgression is called Nehden Event. Nevertheless, timing, evolution rates and magnitude of its influence are still uncertain (Huang et al., 2024 ). Following the Nehden Event, another minor (third order) Global Event took place at the top of the lower Famennian interval, the Condroz Event. This event is widely recorded and related with two regressive pulses (Walliser, 1996 ; Becker and House, 1997 ; Schülke and Popp 2005 ). In the Pyrenees, first studies focused in general stratigraphical and biostratigraphical features of Devonian rocks (Schmidt, 1931 ; Ziegler, 1959 ; Mey, 1967a , b ; Boersma, 1973 ; Zwart, 1979 ). Pioneers works on high–resolution biostratigraphy were carried out in the Central Pyrenees area (Liao and Valenzuela-Ríos, 2008; 2013; Martínez-Pérez and Valenzuela-Ríos, 2014 Martínez-Pérez et al., 2011 ; Gouwy et al., 2013; Valenzuela-Ríos and Liao, 2012; 2024; Valenzuela-Ríos et al., 2015 ; Silvério et al., 2021 ; Slavík et al., 2016), whereas detailed studies on Devonian conodont biofacies are scarce (Sánchez de Posada et al., 2008 ; Liao et al., 2008 ; Liao, 2014 ). Further, upper Frasnian–lower Famennian Global Events are not studied in detail so far, except in Castells area (Fig. 1 c), (Sánchez de Posada et al., 2008 ). Conodont biofacies provide essential information about ecological environments and water depth (Seddon and Sweet, 1971 ; Sandberg, 1976 ). The relative proportions of conodont genera define different assemblages (biofacies) that can be used as a paleobathymetry proxies and its variation through time allows identification of possible sea–level changes (Seddon and Sweet, 1971 ; Sandberg, 1976 ; Sandberg and Dreesen, 1984 ; Girard et al., 2014 ). Additionally, conodont biofacies can be a relevant tool as a palaeoenvitonmental proxy in lithological monotonous section with higher precision than lithofacies analysis (Lüddecke et al., 2017 ). The Central Pyrenees area has numerous, discontinuous, and partial Devonian outcrops. One of them, the Compte section, represents an exception as it exhibits an almost complete Devonian sequence and numerous works on Lower, Middle and recently Upper Devonian biostratigraphy have been published (Valenzuela-Ríos et al., 2005 , 2015 ; Liao and Valenzuela-Ríos, 2008; Martínez–Pérez et al., 2011; Martínez-Pérez and Valenzuela-Ríos, 2014 ; Silvério et al., 2021 ; Barrera-Lahoz et al., 2024 ; 2025 ; Valenzuela-Ríos and Liao, 2012). Thus, the main goals of this study are: to identify and characterize the conodont biofacies within the upper Frasnian to middle Famennian in the Compte section, and through the interpretation of these biofacies, identify the possible eustatic trends and tentatively recognize the position of the Upper Kellwasser, Nehden and Condroz Global Events in this section. 2 Geological setting, material provenance and methods The Compte section is located in the Spanish Central Pyrenees area, which belongs to the Axial zone of the Pyrenean Range (NE Spain) (Figs. 1 a–b). Devonian rocks in the Central Pyrenees area developed in different environments resulting in a complex stratigraphical scheme, which chiefly consists of four main facies–area: North Pyrenean, Northern, Central and Southern (Mey, 1967a , b ; Hartevelt, 1970 ). Furthermore, the Southern facies–area were subdivided in four subfacies–area: Renanué, Sierra Negra, Baliera and Compte (Mey, 1967a ; Zwart, 1979 ; Valenzuela Ríos and Liao, 2006). The Compte section belongs to the latter subfacies–area. The Compte section exhibits mainly limestone and shale from Lower Devonian to Carboniferous. The Upper Devonian consists of three stratiraphical units: Comabella, La Mena and Barousse Formations. The Comabella Fm. is dated as Givetian to lower Famennian age (Liao and Valenzuela-Ríos, 2008; Silvério et al., 2021 ; Barrera-Lahoz et al., 2024 ; 2025 ) and is composed of alternating nodular and bedded, and massive limestones. The La Mena Fm. is dated as lower–middle Famennian (Barrera-Lahoz et al., 2025 ) and is composed of red griotte nodular limestones and intercalated bedded limestones. The Barousse Fm. ranges from middle Famennian to Tournaisian (Boersma, 1973 ; Barrera-Lahoz, 2025) and is composed of nodular and bedded limestones. The main Upper Devonian paleoenvironments of these formations are related with pelagic marine outer platform ramp and hemipelagic condensed carbonate ramp (Liao and Valenzuela-Ríos, 2017 ). The Compte section is located between Gerri de la Sal and Sort localities (Lérida, Spain), 2 km north of the former (42°20'14.2"N, 1°04'04.5"E) at the right bank of the Noguera Pallaresa river. (Figs. 1 b–c) Most of the analyzed material comes Barrera-Lahoz et al., 2024 , (Comabella, La Mena and Barousse Fms., Beds 98–120). Additionally, we revisited the published and unpublished material of Silvério et al., 2021 (Comabella Fm., Beds 84–97). The stratigraphic section analyzed herein is 12.73 m thick and comprises the three cited geological units: Comabella Fm. (Beds 84–105), La Mena Fm. (Beds 106–116) and Barousse Fm. (Beds 117–120). 74 limestone samples were taken in different field campaigns, weighting between 0.025 kg and 3 kg, with a weight average of 0.5–1 kg (Table 1). Almost each bed was sampled and several beds were subdivided taking different samples in the same bed. The rock samples were dissolved in acetic and formic acids (~ 7–8%) in 5–10 liters of water solutions. Later, the undissolved residue was washed and dried, then, it was picked out using LEICA Wild M3B microscope. The selected specimens were photographed through the Scanning Electron Microscope (model Hitachi S4800) at the University of Valencia. The richness of the samples varied, between a minimum of five conodont pectiniform elements (sample CP/105d, with 0.61 kg) and a maximum of 396 (sample CP/89b, with 2 kg). All the samples provide 5656 total conodont pectiniform elements, determined at (sub)species (most) or genus rank. The preservation level was also variable. All of the conodont specimens are actually deposited in the Botany and Geology Department of the University of Valencia. Biostratigraphical zonation has made in agreement with the Frasnian conodont standard zonation of Klapper, 1989 and Klapper and Kirchgasser, 2016 ; and the proposed Famennian conodont standard zonation from Spalletta et al., 2017 . Conventional conodont biofacies have been analyzed following standard models (Sandberg, 1976 , Dreesen & Thorez, 1980 , Sandberg & Dreesen, 1984 and Corradini, 1998 ). The conodont biofacies was based on the counting of conodont specimens per genera and their relative percentages (Table 1). The genera specimens counting included Pa and I elements, juvenile specimens and those fragmentary specimens in which ≥ 60% of platform surface is preserved, allowing generic adscription. Seven genera were identified: Palmatolepis , Polygnathus , Icriodus , Ancyrodella , Ancyrognathus , Mehlina and Pelekysgnathus . Ancyrodella and Ancyrognathus were grouped as ancyrodellids in the specimens counting, due to ecological similitudes. 3 Biostratigraphical framework The biostratigraphical framework provides a detailed conodont zonation across the Frasnian–Famennian boundary, through the middle Famennian (Fig. 2 ). We improved the previous zonation from (Silvério et al., 2021 ) subdividing the FZ13 Zone and the identification of one lower Famennian conodont zone. 3.1 Uppermost Frasnian FZ13 Zone. The lower part of the studied section starts in the FZ13a subzone with the record of its index taxa Palmatolepis bogartensis (sample CP/84); it extends up to sample CP/87b with the highest record of Palmatolepis hassi , which according to Klapper and Kirchgasser ( 2016 ) ranges near to the base of FZ13b subzone. Other conodont taxa recorded in association within this subzone are: Palmatolepis winchelli , Polygnathus webbi , Polygnathus decorosus from the base of this unit, and Polygnathus lodinensis , Polygnathus normalis , Palmatolepis boogaardi , Ancyrodella curvata late form and Ancyrognathus asymmetricus starting the upper half of the zone and Polygnathus politus (unique record in sample CP/85). The lower boundary of the FZ13b subzone is marked by the entry of Palmatolepis linguiformis (Girard et al., 2005 ), however, this taxon is not recorded in the Compte section. Thus, tentatively we place this subzone between the LAD of Palmatolepis hassi (sample CP/87b) and the base of the FZ13c subzone (CP/92 base). Within this zone, all taxa from the previous zone except P. politus and Pa . hassi are recorded. Besides, Icriodus alternatus alternatus appears (sample CP/91-base). Polygnathus decorosus has is LAD at the top of the zone; other taxa continue in the following zone. The base of FZ13c subzone is defined by the LAD of Palmatolepis linguiformis (Girard et al., 2005 ), which is not recorded in the Compte section. However, Palmatolepis ultima appears close to the base (Klapper, 2007 ) and can be used in the section Compte to approximate the base of this subzone (sample CP/92-base). Yazdi ( 1999 ) also considers that Icriodus alt. mawsonae appears in the base of this subzone; the FAD of this taxon in the section Compte is in sample CP/92-base as well. All the conodonts that cross the base of this zone from the previous one disappear within the zone, except Ic. alt. alternatus which crosses de F/F boundary and ends in the lower Famennian termini Zone. Other three new taxa appear in this zone: Palmatolepis ultima , Pa . juntianensis and Ancyrognathus amana (sample CP/92-base); the latter two end in the lower part of the zone. Polygnathus lodinensis , Palmatolepis boogaardi , Ancyrognathus asymmetricus , Polygnathus webbi , Palmatolepis juntianensis and Ancyrognathus amana became extinct around 2 m below, in sample CP/92a. The last record of typical uppermost Frasnian conodont taxa in the Compte section is in sample CP/92b with the LAD of Palmatolepis bogartensis , Palmatolepis winchelli and Ancyrodella curvata late form. Palmatolepis bogartensis , Palmatolepis winchelli , Ancyrodella curvata late form and Ancyrognathus assymmetricus became extinct approximately 50 cm below (CP/92b), whereas Palmatolepis ultima , Palmatolepis ultima , Icriodus alt. alternatus and Icriodus alt. mawsonae crossed the Frasnian–Famennian boundary. 3.2 Palmatolepis delicatula platys and Palmatolepis minuta minuta zones The first Famennian sample (CP/92c) records three Frasnian taxa, Palmatolepis ultima , Icriodus alt. mawsonae and Icriodus alt. alternatus and the entry of Palmatolepis delicatula delicatula , Palmatolepis del. platys , Palmatolepis triangularis and Palmatolepis subperlobata , suggesting the Palmatolepis del. platys Zone, which is defined by the index taxon; the top of the zone is limited by the LAD of Palmatolepis ultima (Spalletta et al., 2017 ). Higher, the sample CP/92d records the FAD of Ancyrognathus sinelaminus and Palmatolepis lobicornis . Due to the high condensation in this part of the section (Silvério et al., 2021 ), the two first Famennian zones ( Palmatolepis subperlobata Zone and Palmatolepis triangularis Zone) are not recorded in the Compte section. The Palmatolepis minuta minuta Zone is identified by the entry of the index taxa in sample CP/93 and is extremely condensed. Palmatolepis del. delicatula ranges up to this zone. 3.3 Palmatolepis crepida and Palmatolepis termini zones. The base of the Palmatolepis crepida Zone is marked by the entry of the index taxon Palmatolepis crepida in sample CP/94a. Concomitant with it, Palmatolepis tenuipunctata , Palmatolepis quadrantinodosalobata and Palmatolepis regularis appear in the base of this zone. Palmatolepis sandbergi is recorded only in this zone, from slightly above the base to the upper half of this zone (samples CP/94b to CP/95). Palmatolepis werneri is also recorded in this zone (samples CP/94c to CP/95). Ancyrognathus sinelaminus ups to the lower half of the zone (CP/94b). Polygnathus communis communis , Pelekysgnathus planus and Palmatolepis mint. loba have the first record of the section in this zone. Palmatolepis triangularis ranges up to the upper half of this zone (sample CP/95). The Palmatolepis termini Zone starts in the base of Bed 96 (sample CP/96) with the first record of the index taxa. Palmatolepis mint. wolskae and Polygnathus gb. eoglaber appear in the base of this zone. 3.4 Palmatolepis glabra prima and Palmatolepis glabra pectinata zones. Barrera-Lahoz et al., ( 2025 ), recognized the Palmatolepis glabra prima and Palmatolepis glabra pectinata zones by their respective index taxa. The base of Palmatolepis glabra prima Zone is located in the upper part of the Comabella Fm. at the top of Bed 98 (sample CP/98c). The base of Palmatolepis glabra pectinata is located in the uppermost part of the Comabella Fm. at the top of Bed 104 (sample CP/104c). Several taxa cross the base of the Palmatolepis gl. prima Zone and have their LAD within the zone: Ic. alt. mawsonae , Palmatolepis tenuipunctata , Palmatolepis quadrantinodosalobata , Palmatolepis crepida , Palmatolepis lobicornis Pa. regularis, Pa. minuta loba , and Pa. termini . Besides, there are two taxa that appear above the base and continue higher in the sequence: Polygnathus gl. glaber (CP/99c) and Polygnathus semicostatus (CP/101b) Except Pa. minuta wolskae , none other taxa crossing the base from the previous zone became extinct in the Palmatolepis glabra pectinata Zone. Three conodont taxa appear slightly above the base and continue higher: Polygnathus nodocostatus nodocostatus and Polygnathus nod. ovatus both in sample CP/105a and Palmatolepis perlobata schindewolfi , in sample CP/105b 3.5 Palmatolepis rhomboidea, Palmatolepis gracilis gracilis and Palmatolepis marginifera marginifera The Palmatolepis rhomboidea, Palmatolepis gracilis gracilis and Palmatolepis marginifera marginifera zones are identified with the appearance of their respective index taxa (Barrera-Lahoz et al., 2025 ). The base of Palmatolepis rhomboidea is located in the lowermost part of the La Mena Fm. (sample CP/107) Within this zone, the conodont association is mainly based on Palmatolepis mint. minuta , Palmatolepis glabra -stock, Palmatolepis perlobata -stock and Polygnathus nodocostatus -stock taxa. Icriodus alt. alternatus ends its record in the upper part of the Palmatolepis rhomboidea Zone (sample CP/111a-1). Along this zone, different taxa appear: Palmatolepis cf. klapperi in the base, Icriodus cornutus in the middle (CP/109b), Polygnathus bouckaerti (CP/110) and Polygnathus eoglaber (CP/111a-1) in the upper half of the zone (for further details see Barrera-Lahoz et al., 2025 ). Near the top of the zone, Palmatolepis gl. acuta (CP/111b) and Palmatolepis gl. lepta (CP/111c) begin its record. The base of the Palmatolepis gracilis gracilis Zone is located at the middle part of La Mena Fm. (base of Bed 112). Two taxa coming from lower zones, end its record in this zone: Polygnathus semicostatus (Bed 112) and Polygnathus padovanii (Bed 113). Polygnathus subnormalis is recorded exclusively in this zone in the Compte section (Beds 112–113). Numerous taxa appear in this zone: Palmatolepis per. helmsi (CP/112a), Polygnathus lauriformis (CP/112c), Mehlina strigosa (CP/112c), Palmatolepis gl. glabra (CP/112d), Polygnathus triphyllatus (CP/112e), Palmatolepis quad. inflexa (CP/112g). Palmatolepis stoppeli is recorded near the top of this zone (CP/113c). The base of the Palmatolepis marginifera marginifera Zone is located in the upper part of La Mena Fm. (base of Bed 114) and it is marked by the appearance of the index taxa, which is accompanied by Palmatolepis quad. quadrantinodosa and Palmatolepis quad. inflexoidea (CP/114a). Polygnathus glaber medius and Palmatolepis per. sigmoidea start in sample CP/117, whereas Polygnathus longiusculus appears in sample CP/118b. Numerous taxa end its record in this zone: Polygnathus com. communis (CP/114a), Polygnathus nod. ovatus (CP/114b), Polygnathus nod. nodocostatus (CP/116), Mehlina strigosa (CP/114b), Palmatolepis gl. prima and Palmatolepis gl. acuta in CP/117, Polygnathus triphyllatus CP/118a and Palmatolepis mint. minuta and Palmatolepis per. helmsi in CP/119. 4 Conodont biofacies Seddon (1970) started the study of the conodont biofacies defining the neritic–reef Icriodid and Palmatolepid pelagic facies from the Upper Devonian in the Canning Basin. Later, Seddon and Sweet (1971) proposed a paleoecological model for the conodont facies and its distribution related to water depth. Seddon and Sweet (1971) and, subsequently, Sandberg (1976) demonstrated the relation between the proportion of conodont genera and water depth Thus, the conodont biofacies were established as water depth approximation proxy. Sandberg (1976) defined five new biofacies from the late Famennian styriacus Zone (applicable to other Famennian zones): Palmatolepid–Bispathoid, Palmatolepid–Polygnathid, Polygnathid–Icriodid, Polygnathid–Pelekysgnathid and Clydagnathid. Dreesen and Thorez (1980) described the ecological distribution of Polylophodonta and polygnathids of the P. semicostatus and nodocostatus groups from the Famennian of Belgium. Sandberg and Dreesen (1984) reviewed the shallow water environments conodont zonation and included a new Anthognathid biofacies for hypersaline environments. Savoy and Harris (1993) reported the conodont biofacies separating species in morphological groups from the Devonian and lowermost Carboniferous of the Rocky Mountains. Matyja (1993) analyzed new Polygnathid–Palmatolepid biofacies and mentioned conodont species distribution in biofacies from Western Pomerania region, Poland. Corradini (1998) documented new deep water Palmatolepid–Icriodid biofacies, specifically cosmopolitan icriodid taxa in the Devonian of Sardinia, Italia. Later, Lüddecke et al. (2017) described detailed biofacies based on conodont species groups in the middle Famennian of the Rhenish Massif (Germany); however, Girard et al. (2020) challenged this approach, as it is difficult to apply in relative long–time record, due to the species evolution and replacement. We agree with this latter opinion. The combination of conodont records in the Compte section allows recognition of five biofacies (Fig. 3). Palmatolepis is always present in the studied time-interval, representing the 65% of the total specimens. Polygnathus is the second most abundant genus representing the 27%, but in several levels is absent. Less proportion have Icriodus , 5%, Ancyrodellids 1% (including together the genera Ancyrodella and Ancyrognathus ), Mehlina and Pelekysgnathus both contains less than 1% of all specimens. 4.1 Conodont biofacies description. Palmatolepis biofacies. The most abundant genus is Palmatolepis counting for between the 75–98% of the total specimens Polygnathus represents 1–23% or it is absent in some samples (Tab. 1). Icriodus represents 2–17% or is lacking (Tab. 1). Ancyrodellids are scarce representing 2–9%. Mehlina is residual, recorded only in one sample (CP/114b) where it represents 0.9%. Palmatolepis – Polygnathus biofacies. Palmatolepis represents the most abundant genus, but in lesser proportion than in the Palmatolepis biofacies. The percentage comprises between the 50–75% of the total specimens. Polygnathus is abundant reaching the 20–46%. Polygnathus semicostatus is the most abundant taxon in CP/110 and CP/111a-1 and the nodocostatus group and Polygnathus lauriformis are frequent in Beds 112–114, specially in CP114/a (see tables in Barrera-Lahoz et al., 2025 for specimens count per taxon). Icriodus and Ancyrodellids represent at least 2–6% or are absent. Mehlina is accessory in four samples, representing only 2–5% of the total specimens. Polygnathus – Palmatolepis . Polygnathus is dominant with the 60–80% of the total specimens. Polygnathus lodinensis and Polygnathus decorosus are the frequent taxa through the Frasnian, whereas Polygnathus semicostatus and Polygnathus of the nodocostatus group are the common Famennian taxa. The second abundant genus is Palmatolepis representing the 12–40% of the total specimens. When present, Icriodus and Ancyrodellids are less common, representing between 1–6%. Palmatolepis – Icriodus . Palmatolepis is the most frequent genus counting for the 80–54% of the total specimens and Icriodus the second, representing between the 6%–38% of the total specimens. Other accessory genera, always being less numerous than Icriodus , are Polygnathus between 4–10% and Ancyrodellids, up to 10%. Icriodus – Palmatolepis . This new biofacies is characterized by Icriodus peaks, representing the most frequent genus, reaching up to 49% of the total specimens; Palmatolepis around 34% of total specimens is the second. The Icriodus representative taxa are cosmopolitan species of the alternatus group: Icriodus alt. alternatus and Icriodus alt. mawsonae , and the Pyrenean Icriodus tumulosus . Accessory Polygnathus represents 18–22% of the total specimens. 4.2 Conodont biofacies evolution through the Compte section (Figure 3) Polygnathus dominates the conodont fauna between Beds 84–87, which belongs to most of the FZ13a subzone (Fig. 3); it represents around 52% with the Polygnathus – Palmatolepis biofacies. The frequent polygnathid taxa are Polygnathus webbi , Polygnathus decorosus , Polygnathus lodinensis , Polygnathus politus . The common palmatolepids are Palmatolepis hassi , Palmatolepis winchelli and Palmatolepis bogartensis . The presence of Icriodus and Ancyrodellids is low (<3%), in most of the FZ13a–b subzones. The Polygnathus content descends to 36% in Bed 87, through FZ13a–b subzones boundary and the Palmatolepis richness increases to 57%, turning into the Palmatolepis – Polygnathus biofacies. Then, the Polygnathus content sharply increases up to 71%, returning the Polygnathus – Palmatolepis biofacies in the base of Bed 89, in the lower part of FZ13b subzone, being Polygnathus decorosus and Polygnathus lodinensis the dominant taxa. Slightly higher, the Palmatolepis – Polygnathus biofacies returns (Beds 89–90; Fig. 3); subsequently, the Polygnathus – Palmatolepis biofacies dominates most of the upper half of this subzone (Bed 91). Then, a sudden peak of Palmatolepis (81%) at the top of Bed 91(uppermost FZ13b), represents the change to the Palmatolepis biofacies. Higher, in the FZ13c subzone, the Polygnathus proportion increases (9–30%) returning the Palmatolepis – Polygnathus biofacies. Alongside FZ13c subzone, the abundance of Icriodus and Ancyrodellids gradually increases reaching up to 20% and 10% respectively, at the top of this subzone. This Icriodus peak resulted in the incoming of the Palmatolepis – Icriodus biofacies at the end of the Frasnian in the Compte section. Within the lowest recorded Famennian Biozone ( Palmatolepis del. platys ), two biofacies are observed, the Palmatolepis – Polygnathus (sample CP/92c) followed by the Palmatolepis – Icriodus biofacies (sample CP/92d). Immediately above, in the “condensed” Palmatolepis mint. minuta Zone, a second Icriodus peak is recorded (49% of specimens abundance) resulting in the Icriodus – Palmatolepis biofacies in sample CP/93. This peak is due to Icriodus alt. alternatus . Palmatolepis counts for the 47% of the total specimens, and it is represented by the delicatula group, Palmatolepis mint. minuta , Palmatolepis triangularis and Palmatolepis lobicornis . Polygnathus is accessory, almost 3%. After this Icriodus peak, the icriodid content decreases in the base of Palmatolepis crepida Zone with Palmatolepis – Icriodus biofacies and Palmatolepis recovers its dominance through this zone and during the Palmatolepis termini and the lowermost part of the Palmatolepis glabra prima zones, with an average of 80%, reaching a maximum of 98% at the base of Palmatolepis termini Zone. Polygnathus decreases gradually its abundance from 17 to 1% through the crepida Zone and then, keeps a moderated low abundance between 14 to 1%. Icriodus recovers its abundance in the upper part of termini Zone, reaching up to 19%. Accessory genera in this biofacies are Ancyrodellids with 2% in the lower part of the Palmatolepis crepida Zone and Pelekysgnathus with 1% at the top of this zone. Higher, three Icriodus peaks are recorded within the Palmatolepis gl. prima Zone, resulting in an alternation of Palmatolepis – Icriodus and Palmatolepis biofacies during this zone. The first peak occurs at the lower part of the zone, and the other two in the middle parts. As in the previous Famennian zones, the Icriodus alternatus group is the dominant icriodid. Polygnathus maintains a low percentage reaching a maximum of 11% (Bed 100) and being absent in several samples, e.g. CP/104a (Tab. 1). Through the middle part of the Palmatolepis gl. prima Zone, the abundance of pectiniform conodonts is relatively low; bed 100 yielded 8 specimens, and through the upper part of the zone its richness increased moderately (22–59 specimens). In the highest sample of the zone (CP/104b), a sharply palmatolepid bloom is recorded, reaching 147 specimens (Tab. 1), 98% of which belong to Palmatolepis . Palmatolepis gl. prima , Palmatolepis crepida , Palmatolepis tenuipunctata and Palmatolepis quadrantinodosalobata are the frequent taxa; the latter three have their highest record in this zone. A new Icriodus peak (48%) is recorded in the base of the Palmatolepis gl. pectinata Zone (sample CP/104c), returning the Icriodus – Palmatolepis biofacies. Icriodus tumulosus , endemic taxon in the Pyrenees, is the only icriodid in this biofacies. Palmatolepis represents the 34% and Polygnathus reaches the 18%. Higher in the zone, the abundance of Polygnathus increases (60% to 80% of the specimens) peaking in Bed 105 (Tab. 1); thus, the Polygnathus – Palmatolepis biofacies is recorded through this zone. The common polygnathids are Polygnathus semicostatus and Pol . of the nodocostatus group, whereas Polygnathus padovanii and Polygnathus com. communis are accessory. The record of Icriodus in this zone is limited to two samples, (CP/104c -the peak one- and CP/105a) . The Palmatolepis biofacies sharply appears in the base of the subsequent Palmatolepis rhomboidea Zone, with 90% of abundance in the base of Bed 107; the other 10% corresponds to Polygnathus . The increase in the number of polygnathids leads to the Palmatolepis – Polygnathus biofacies up to middle parts of the zone (sample CP/109a). Then, a new (and last one) icriodid peak (sample CP/109b) marks the Icriodus – Palmatolepis biofacies, with Icriodus reaching at least 44% and Palmatolepis 33%. From this sample to the sample CP/111b the Palmatolepis – Polygnathus biofacies continues. The increase in the number of Palmatolepis across the boundary between the Pa. rhomboidea and the Palmatolepis gr. gracilis zones results in the returning of the Palmatolepis biofacies in the base of Bed 112. Higher, Palmatolepis reaches up to the 76–80% of the total specimens. Representative taxa are Palmatolepis glabra stock Polygnathus padovanii , Polygnathus triphyllatus and Polygnathus lauriformis . Mehlina appears as accessory with 2%. The progressive augment of Polygnathus , with a maximum in sample CP/113a (54%) results in the re-occurrence of the Polygnathus-Palmatolepis biofacies. The Palmatolepis – Polygnathus biofacies returns from the upper part of Bed 113 through the base of Bed 114, where corresponds to the lowest interval of Pa. mag. marginifera Zone. Palmatolepis is the dominant genus from the lower part of the Palmatolepis mg. marginifera Zone to the end of the section (Beds 114–120), with values between 75–89%, resulting in the return of the Palmatolepis biofacies, Representative palmatolepid taxa in this zone are those of the Palmatolepis glabra , Palmatolepis perlobata and Palmatolepis quadrantinodosa groups and Palmatolepis mint. minuta . The Polygnathus percentage ranges between 11–20% of the total specimens. 5 Discussion 5.1 Paleoecological interpretations . Upper Devonian conodont biofacies provide information on relative water depth of depositional environments and eustatic changes, especially in monotonous stratigraphical sequences (Lüeddecke et al., 2017). Palmatolepis , Mehlina , Branmehla and Bispathodus are often related with deep waters or offshore environments (Sandberg, 1976 ). Polygnathus is related with intermediate waters, shallower than Palmatolepis (Sandberg, 1976 ). Icriodus is related to shallow waters (Sandberg, 1976 ; Sandberg and Dreesen, 1984 ), however, several cosmopolitan taxa, as those of the alternatus group, Icriodus olivierii and Icriodus cornutus are found in pelagic environments (Corradini, 1998 , 2003 ). As previously mentioned, the conodont succession in the Compte section shows different faunal changes and alternance of biofacies. The first of these changes occurs in the upper part of the FZ13a where the Polygnathus – Palmatolepis is replaced by the Palmatolepis – Polygnathus biofacies suggesting a transgressional trend. A Polygnathus peak in the lower part of FZ13b subzone leads to the return of the Polygnathus – Palmatolepis biofacies (Fig. 3 ) and is interpreted as a regressive trend with the Polygnathus peak in the base of Bed 89 ( Polygnathus – Palmatolepis biofacies). Palmatolepid–Polygnathid biofacies returns through the middle of FZ13b subzone. Another Polygnathus peak is recorded in the upper half of this subzone (Bed 91) suggests another regressive trend. Near to the top of FZ13b subzone (Fig. 3 ), a sharply dominance of Palmatolepis ( Palmatolepis biofacies) is recorded. Thus, the abrupt increase of Palmatolepis suggests a markedly transgressive trend. During the FZ13c subzone Icriodus increases gradually, reaching a maximum of 20% in sample CP/92b ( Palmatolepis – Icriodus biofacies). The Palmatolepis – Polygnathus biofacies dominates through the FZ13c subzone; however, near the top, the occurrence of the Palmatolepid–Icriodid biofacies suggests a regressive trend close to the Frasnian–Famennian boundary. During the Palmatolepis del. platys and Palmatolepis mint. minuta zones the icriodid content remains high, reaching 49% in sample CP/93; consequently, the Icriodus – Palmatolepis biofacies develops in the Palmatolepis mint. minuta Zone. This high icriodid content may suggest a regressive trend, nevertheless, opportunistic taxa as those of the alternatus group might also be present in pelagic facies occupying empty ecological niches after the extinction event (Corradini, 1998 ; 2003 ). The significant content of Icriodus suggests shallower conditions than those of the Palmatolepid–Icriodid biofacies, probably as result of transport of shallower sediments related with eustatic sea–level fall in the carbonated ramp. The Icriodus content decreases through the Palmatolepis crepida and Palmatolepis termini zones where the Palmatolepis biofacies is almost exclusive, suggesting a transgressive trend. The small in the Palmatolepis crepida Zone content of Pelekysgnathus is interpreted as result of transport from the nearshore area. During the Palmatolepis gl. prima , three icriodid peaks ( Palmatolepis – Icriodus biofacies) are recorded in Beds 99, 101 and 102, which could suggest short regressive fluctuations. In the upper part of the Palmatolepis gl. prima Zone (sample CP/104b) a bloom of palmatolepids is recorded, reaching 98% of the total species suggesting a sharply transgressive trend. The beginning of the Palmatolepis gl. pectinata Zone records an abrupt change of biofacies: Icriodid–Palmatolepid (indicate samples) followed by the Polygnathid–Palmatolepid biofacies (samples); these biofacies change may be the expression of a new regressive trend. The polygnathid taxa in the Polygnathid–Palmatolepid biofacies (Fig. 2 ) are found in shallower environments (Dreesen and Thorez, 1980 ), thus, a regressive trend through the Palmatolepis gl. pectinata is plausible. The abrupt return of the palmatolepid dominance at the base of Palmatolepis rhomboidea Zone suggests deeper pelagic conditions, which are interrupted by the next icriodid peak leading to the Icriodid–Palmatolepid biofacies in the middle of the Palmatolepis rhomboidea Zone (Bed 109), suggesting a sharply sea–level fall. The restore to abundance of Palmatolepids and of the Palmatolepid–Polygnathid biofacies suggests deeper conditions through the upper part of the Palmatolepis rhomboidea Zone. This deepening trend continues in the transition between the Palmatolepis rhomboidea and Palmatolepis gr. gracilis zones. The following Palmatolepid–Polygnathid biofacies, and specially, the subsequent Polygnathus – Palmatolepis biofacies in the Palmatolepis gr. gracilis Zone (Bed 113) suggest another regressive pulse. During the upper part of the Palmatolepis gr. gracilis Zone and the Palmatolepis mg. marginifera Zone, the dominance of Palmatolepis biofacies suggests deeper water environments, and, thus, a new transgressive pulse. 5.2 Conodont biofacies evolution and diversity comparison with other regions . Through the Frasnian–Famennian boundary biotic changes in the conodont faunas are recorded worldwide. These changes seem to be connected with eustatic fluctuations at the end of the Frasnian extinction (Sandberg et al., 1988 ). Ancyrodella and Ozarkodina became extinct at the end Frasnian, and Palmatolepis was reduced to a unique taxon: Palmatolepis ultima . All species of Frasnian Polygnathus disappear and Icriodus did not suffer a major extinction event; a characteristic peak of Icriodus is recorded in different Euramerican zones in the basal Famennian interval (Sandberg et al, 1988 , Schülke and Popp, 2005 , Girard et al., 2014 ). Through the lower and middle Famennian different conodont biofacies shifts are recorded in several regions; thus, a comparison with those changes recorded in the Compte section is possible. In the Central Pyrenees, Els Castells section, (Fig. 1 c; Fig. 4.1), different conodont biofacies are recorded through Frasnian–Famennian transition (Sánchez de Posada et al., 2008 ). Within FZ13, Palmatolepis – Polygnathus is the frequent biofacies, like in the Compte section where polygnathids are frequent in the lower part of the zone. The last Frasnian sample in Els Castells shows a maximum abundance of Palmatolepis , contrasting with the Palmatolepid–Icriodid biofacies in the Compte section. The first four Famennian samples belonging to the Palmatolepis del. platys – Palmatolepis mint. minuta zones show a dominance of Palmatolepis – Icriodus biofacies, with a peak of Icriodus in the Palmatolepis del. platys Zone in Els Castells, unlike the sharply Icriodus peak in Compte section during the Palmatolepis mint. minuta Zone. Similar biofacies with the studied section are found in the Palentine Domain in the Cantabrian Zone (Fig. 4.2): Palmatolepis – Polygnathus within the upper Frasnian and Palmatolepis – Icriodus in the lower Famennian (Sanz-López et al., 1999 ). Within the lower Famennian ( Palmatolepis subperlobata to Palmatolepis gr. gracilis zones) the frequent biofacies in Col des Tribes section, Montagne Noir (Fig. 4.3) is the Palmatolepis – Icriodus (Girard et al., 2014 ). During the Palmatolepis termini Zone, a minor icriodid peak (< 25%) is recorded like in the Compte section. The abrupt palmatolepid abundance, in Palmatolepis termini – Palmatolepis gl. prima transition in Compte section, is recorded at the top of Palmatolepis termini Zone in Col des Tribes. There, in the base of the Palmatolepis gl. prima Zone another Icriodus peak, reaching 25% is recorded, similar with the studied area; however, the icriodid content decreases through this zone in Col des Tribes section, whereas other two icriodid peaks are recorded in the Compte section. During the Palmatolepis gl. pectinata Zone the icriodid content is present but in the base of the Palmatolepis rhomboidea Zone a Palmatolepid abundance similar to the Compte section is recorded. A minor Icriodus peak is recorded in the Palmatolepis gr. gracilis Zone, whereas this peak is not recorded in the Compte section. In the Palmatolepis mg. marginifera Zone the Palmatolepis biofacies is dominant, similar to the Compte section. In the Coumiac section, slight differences related to fluctuations of icriodid abundance percentage (Schülke, 1999 ), in the Palmatolepid–Icriodid biofacies through Palmatolepis subperlobata – crepida zones are observed. The end of the Frasnian is characterized there by a polygnathid abundance up to 55%, higher than in the Compte section. During the Palmatolepis crepida Zone an icriodid peak (reaching 30%) was recorded showing difference with the palmatolepid dominance in the Compte section during this time. A second icriodid peak was identified during the Palmatolepis termini Zone (reaching near to 50%) and shows a slightly similarity with minor peak in the Compte section. The entry of Palmatolepis gl. prima is similar in these two sections with a minor Icriodus peak. Palmatolepids and polygnathids are the most abundant genera in Sardinia (Fig. 4.4) through lower and middle Famennian (Corradini, 2003 ). Contrasting, the records in the Compte section show an abundance of palmatolepids and Palamatolepis – Icriodus biofacies dominate during the Palmatolepis crepida – Palmatolepis termini zones. During the Palmatolepis termini – Palmatolepis gl. prima transition a high abundance of palmatolepids is recorded, similar with the studied section. Within Palmatolepis gl. prima Zone, palmatolepids are more abundant and in the Palmatolepis gl. Pectinata Zone, the Palmatolepis – Icriodus biofacies returns. The Palmatolepis – Polygnathus biofacies dominate through Palmatolepis rhomboidea to Palmatolepis mg. marginifera zones. Two recorded Icriodus peaks in Sardinia are similar with those in the Compte section: the first in the lower part of the Palmatolepis gl. pectinata Zone and the second in the middle part of the Palmatolepis rhomboidea Zone. During the FZ13 polygnathids are relative frequent in the Carnic Alps (Fig. 4.5) (Farabegoli et al., 2023 ), however, from the upper part of the FZ13b subzone, their abundance decreases. Palmatolepis , similar with the Compte section, reaches high abundance in the uppermost part of the FZ13b subzone and keeps abundant through the Palmatolepis mint. minuta Zone. Palmatolepis reaches 70–80% of abundance during the Frasnian–Famennian transition in the Carnic Alps. Palmatolepid biofacies is frequent in the lower Famennian and Polygnathid biofacies is present in the FZ13a subzone and Palmatolepis termini Zone. In the Carnic Alps, Icriodus is scarce in the middle of the FZ13b subzone, in the middle of the Palmatolepis gl. prima and in the Palmatolepis rhomboidea zones, similar with Compte section. The Icriodus peaks are recorded in the FZ13c subzone and the Palmatolepis mint. minuta Zone share similarities with the Compte section, however, the peaks in the Palmatolepis crepida Zone and in the top of the Palmatolepis gl. pectinata do not correspond with those peaks in the Compte section. Palmatolepid–Polygnathid biofacies is present during the FZ13 in the Moroccan Central Massif, Atlas Range (Fig. 4.6) (Lazreq, 1999 ). This biofacies continues within the lower Famennian up to the Palmatolepis termini Zone and Palmatolepis represents between 65–75%. From the Palmatolepis gl. prima – gl. pectinata upwards, the content of palmatolepids is higher, turning into the Palmatolepis biofacies. This succession is different from the Compte section during this interval. The Palmatolepis – Polygnathus biofacies returns within the Palmatolepis rhomboidea – gr. gracilis zones. Similar biofacies as in the Compte section are found in M’rirt area (Lazreq, 1992 ), which starts in the end of the Frasnian with Palmatolepis – Polygnathus biofacies. The icriodid abundance increases gradually up to the F/F boundary with relative abundance of ancyrodellids. However, the Moroccan Palmatolepis biofacies is recorded from the Palmatolepis mint. minuta Zone until the Palmatolepis gl. pectinata . The Palmatolepis – Polygnathus biofacies is present again from the Palmatolepis rhomboidea to the Palmatolepis mg. marginifera zones. In the end of the Frasnian sequence, Palmatolepis is the most abundant genus with up to 70%, followed by Polygnathus with up to 15%, showing the palmatolepid biofacies in the Thuringian zone (Fig. 4.7) (Girard et al., 2017 ). In the lower Famennian Palmatolepis crepida Zone, the percentage of Icriodus increases, opposite to the Compte section. In Thuringia, palmatolepids are more abundant, reaching the 90%, from the Palmatolepis termini . Also, a Polygnathus peak (25%) is recorded in the Palmatolepis termini Zone in contrast with the records in the Compte section. Palmatolepid and Polygnathid biofacies dominate the end of the Frasnian sequence in Western Pomerania region (Fig. 4.8) (Matyja, 1993 ). The Polygnathus – Palmatolepis biofacies is frequent in the FZ12–FZ13, reaching up to 50% of Polygnathus webbi . During the FZ13b–c subzones the Palmatolepis – Polygnathus biofacies dominates showing some similarities with the Compte section, including the ruling abundance of Palmatolepis winchelli (58% of total specimens). During the Palmatolepis subperlobata – Palmatolepis mint. minuta zones the change of biofacies is too different with the Compte section. In both areas the Icriodus – Polygnathus biofacies develops, but the frequent taxa in Western Pomerania are Icriodus of the alternatus -stock, Polygnathus praecursor and Polygnathus procerus . Similar Icriodus peak (51%) is recorded in the Palmatolepis mint. minuta Zone in both regions, however the secondary genus is Polygnathus in contrast to the Compte section where the secondary is Palmatolepis . From the Palmatolepis crepida Zone through the Palmatolepis gr. gracilis Zone, the sedimentary deposits are much deeper, similar to those of the Compte section. There is a sedimentation change at the entry of the Palmatolepis mg. marginifera Zone, with shallower biofacies: Polygnathus – Palmatolepis biofacies. The Palmatolepid–Polygnathid biofacies is recorded in the Holly Cross Mountains (Fig. 4.9) (Matyja and Narkiewicz, 1992 ) during the upper part of the FZ13, with a low number of icriodids. At the uppermost Frasnian, the relative abundance of Polygnathus decreases, similar with the decline observed in the Compte section. The faunistic composition changes in the lowermost Famennian ( Palmatolepis subperlobata – triangularis zones) with a dominance of Icriodus , reaching up to 53%, which is assigned to the Palmatolepis – Icriodus mixed biofacies slightly similar with Compte section. The predominant biofacies from all sections of the South Urals region (Fig. 4.10) (Tagarieva, 2013 ) is the palmatolepid biofacies in Bol’shaya Barma section. During the FZ13a–b subzones in all Russian sections, the biofacies shows a major content of palmatolepids than the Compte section. Near to the F/F boundary in the FZ13c subzone, the icriodid biofacies is present in Akkyr, Ryauzyak and Kuk-Karauk sections, whereas the Palmatolepid–Polygnathid biofacies dominates in the Bol’shaya Barma section, as in the Compte section. Through the F/F transition in the Akkyr section, the conodont diversity decreases and Icriodus rises its relative abundance, thus, the Icriodus biofacies is recorded to the Palmatolepis del. platys Zone, whereas in the Compte section, the Palmatolepid–Polygnathid biofacies develops. In the Bol’shaya Barma section, Icriodus is absent, keeping the Palmatolepis – Polygnathus biofacies through the Palmatolepis mint. minuta Zone, contrasting with the icriodid peak in the Compte section. The abundance of Palmatolepis grows from the Palmatolepis crepida to the Palmatolepis mg. marginifera zones, showing Palmatolepis biofacies in all Russian sections; however, the Compte section shows more biofacies variation during this time. The lowermost Famennian in the Central Iran region (Fig. 4.11) (Bahrami et al., 2020 ) is characterized by an Icriodus peak (almost 50%) in the Palmatolepis subperlobata Zone and by a Palmatolepis abundance (reaching 80%) through the Palmatolepis mint. minuta Zone with a strong icriodid peak in the middle part of the Palmatolepis mint. minuta Zone coincident with the Compte section, whereas different Polygnathus – Icriodus biofacies is present during the Palmatolepis crepida – gl. pectinata zones. Slightly similar shallow facies in the Palmatolepis rhomboidea and Palmatolepis gr. gracilis zones, with polygnathid biofacies dominance are observed in both regions. A Pelekysgnathus peak, reaching almost 50% of the genera abundance is recorded in the Palmatolepis gr. gracilis Zone. From the Palmatolepis mg. marginifera Zone, Palmatolepis are sharply abundant, about 70–80%, which is slightly similar with the records in the Compte section. In Baruunhuurai Terrane, western Mongolia (Suttner et al., 2020 ) different biofacies are recorded during the Palmatolepis mint. minuta to the Palmatolepis gl. prima zones, being the most characteristic the Polygnathus – Palmatolepis biofacies (Fig. 4.12). The most significant difference with the Compte section is the relative abundance of Ancyrognathus in Mongolia, even though palmatolepids and polygnathids are the most numerous genera. At the Palmatolepis rhomboidea Zone, Palmatolepis increases its abundance. Icriodids are less abundant than in the Compte section, with two minor peaks in Palmatolepis crepida and Palmatolepis gl. prima zones. Palmatolepids are the most abundant taxa within the FZ13 in the Lali section in Guangxi region (Fig. 4.13) (Zhang et al., 2019 ), this abundance reaches almost 90%, however, in some samples polygnathids are important components of the biofacies, 60% of Palmatolepis and 36% of Polygnathus . A peak of Icriodus , reaching 45%, characterizes the lowermost Famennian ( Palmatolepis subperlobata Zone), whereas Palmatolepis reaches 37%. These relative abundances are similar to the Icriodus – Palmatolepis biofacies in the Compte section. Then, the Palmatolepis / Icriodus ratio reverses (61% and 31%), indicating the Palmatolepis – Icriodus biofacies. This biofacies is recorded in the base of the Palmatolepis del. platys Zone and continues through the Palmatolepis mint. minuta – crepida zones Higher, in the upper half of Palmatolepis crepida to termini zones, the Palmatolepis abundance is greater, reaching the 95%. Within the Palmatolepis crepida Zone, Icriodus reaches between 15–24%. In the Palmatolepis gl. prima Zone, the content of Icriodus is around 23–28% except in the top of this zone, where a Palmatolepis peak reaching almost 100%, is recorded. This is similar in the Compte section. The Palmatolepis biofacies is the dominant through the Palmatolepis gr. gracilis to Palmatolepis mg. marginifera zones. In the Yangdi section (Fig. 4.13) (Huang and Gong, 2016 ), the Palmatolepis biofacies is the dominant during the FZ13a subzone, except for a high percentage of Polygnathus at the top of this subzone. At the base of FZ13b subzone, as in the Compte section, a Palmatolepis peak is recorded, followed by an increase in the Polygnathus abundance resulting in the Palmatolepis – Polygnathus biofacies through the middle and upper part of this subzone and the following FZ13c subzone. At the top of the Frasnian, the increase in Icriodus , which reaches 27%, develops the Polygnathus – Icriodus biofacies. In the lowermost Famennian, Icriodus keeps the abundance, almost 53%, followed by palmatolepids and a low abundance of polygnathids, turning the Palmatolepid–Polygnathid into the Palmatolepid–Icriodid mixed biofacies. This biofacies ranges to the Palmatolepis del. platys Zone and then, the Palmatolepis biofacies is present through the Palmatolepis crepida Zone. The Lali section shows some similarities with the distribution of biofacies in the Compte section. They are comparable in the high content of icriodids, showing Palmatolepid–Polygnathid biofacies in Palmatolepis del. platys to Palmatolepis crepida zones, and several peaks in Palmatolepis gl. prima Zone. The bloom of Palmatolepis in the upper part of Palmatolepis gl. prima Zone is comparable to the Compte section. On the other hand, in the Yangdi section the Polygnathid–Palmatolepid biofacies during the latest Frasnian (FZ13a–c) is comparable with the Compte section, nevertheless, the lower Famennian biofacies content is too different between the Chinese and Pyrenean sections. In the Indiana region (USA), the Palmatolepid–Polygnathid biofacies dominates through the upper Frasnian to lower Famennian (Fig. 4.14) (Sandberg et al., 1994 ). During the FZ13 the NorthAmerican Palmatolepid–Polygnathid biofacies is different from the Compte section, where two polygnathid peaks are recorded. The icriodid content (0–6%). is low in the Palmatolepis del. platys Zone, In the Palmatolepis crepida Zone, the high percentage of Palmatolepis indicates the Palmatolepis biofacies, which is comparable with Compte section. During the upper Frasnian, palmatolepids and polygnathids have high relative abundance in the USA Great Central Basin (Fig. 4.15) (Morrow, 2000 ) with a peak of Polygnathus in the FZ13b–c subzones, similar to Compte section. The lower Famennian ( Palmatolepis subperlobata – triangularis zones) is characterized by a high percentage of Icriodus , reaching 50%, especially within the Palmatolepis triangularis Zone. From the Palmatolepis del. platys Zone, there is an increase in the number of taxa of Palmatolepis and Polygnathus , however, the percentage of Icriodus continues being relatively high through the Palmatolepis mint. minuta Zone. The Compte section shows similarities and discrepancies with different localities from Euramerica, Gondwana, Uralian Arc, Iran Block, Central Asian Orogenic Belt and South China Block in the relative proportions of conodont genera abundance and, consequently in the distribution and evolution of conodont biofacies from the upper Frasnian to the middle Famennian. During the FZ13, polygnathids are relative abundant until the top of FZ13b subzone, alternating the biofacies of Polygnathus – Palmatolepis and Palmatolepis – Polygnathus biofacies in East Euramerica (Europe) and South China regions (Matyja, 1993 ; Zhang et al.; 2019 , Farabegoli et al., 2023 ) as in the Compte section, with difference in the Uralian Arc region (Tagarieva, 2013 ). The increase in species of Icriodus in the Compte section, which leads to a different biofacies, the Palmatolepis – Icriodus , near to the end of the Frasnian, is also observed in several sections of North Gondwana (Africa), West Euramerica (North America), East Euramerica (Europe) and South China regions (Lazreq, 1992 ; Morrow, 2000 ; Huang and Gong, 2016 ; Zhang et al., 2019 ; Farabegoli et al, 2023 ). The extinction associated with the Kellwasser Event(s) and the transgressive event followed by a sharply regression (Johnson et al., 1985 ; Sandberg et al., 1988 , Carmichael et al., 2019 ) marks the F/F and the lowermost Famennian, which coincides with the Icriodus abundance (Sandberg et al., 1988 ; Girard and Renaud, 2007 ). However, and due to the high condensation in the Compte section, the lowermost Famennian has not been identified in this section yet. The Palmatolepis del. platys – mint. minuta interval is characterized by high relative proportions of Icriodus resulting in successions of Palmatolepis-Icriodus and Icriodus-Palmatolepis biofacies, including a peak of Icriodus . This is also observed in the East Euramerica (Europe), North Gondwana (Africa), South China and Iran regions (Schülke, 1999 ; Lazreq, 1999 ; Schülke, 2003 ; Zhang et al., 2019 ; Bahrami et al., 2020 ; Farabegoli et al., 2023 ). The presence of icriodids is high in different beds of the succeeding Palmatolepis crepida and Pa. termini zones in East Euramerica (Europe) (Schülke, 2003 ; Schülke and Popp, 2005 ; Girard et al., 2014 ). However, in the Compte section, the great abundance of the pelagic palmatolepid outnumbers other genera and causes that these two zones record exclusively the Palamatolepis biofacies. Icriodids and palmatolepids alternate the highest abundance during the Palmatolepis gl. prima and the base of the Pa. gl. pectinata zones, with an icriodid peak in the latter level; similar record is observed in Sardinia (Corradini, 2003 ). From the Palmatolepis rhomboidea Zone to Pa. mg. marginifera Zone, the icriodids abundance decreases and Palmatolepid and Polygnathid biofacies are the dominant worldwide; however, in the Compte section, the last icriodid peak is recorded in the middle of the Pa. rhomboidea Zone; this peak is also recorded in several European regions, Sardinia (Corradini, 2003 ), Carnic Alps (Farabegoli et al., 2023 ) and Montagne Noir (Girard et al., 2014 ). The different position of the Icriodus peaks in the Compte section, may be caused by local conditions and sedimentary environments or the occupation of empty niches by Icriodus (Corradini, 1998 , 2003 ). During the Palmatolepis gr. gracilis – mg. marginifera zones Palmatolepid and Polygnathid biofacies still are the dominant in the Compte section, similar to other regions in East Euramerica (Europe), Uralian Arc and South China (Corradini, 2003 ; Tagarieva, 2013 ; Girard et al., 2014 ; Zhang et al., 2019 ; Farabegoli et al., 2023 ). 5.3. Global Events in the Compte section. As aforementioned, the lithological expressions of the Late Frasnian–Early Famennian Global Events are not recorded in the section Compte. Thus, the suggested position of them is based on the effects of these Events in the conodont faunas and in the corresponding stratigraphical position. Kellwasser Events. During the end of the Frasnian biotical crisis, there are two different Global Events recognized worldwide, the Lower and Upper Kellwasser Events (Schindler, 1990 ). The definition of these events was established in the Kellwasser Kalk section in the Harz Mountains, Germany, which are two dark shales levels separated by limestones (Schindler, 1990 ; Buggisch, 1991 ). The Lower Kellwasser Event is recorded in the transition between FZ12 and FZ13a subzone and the Upper Kellwasser Event in the top of FZ13c subzone (Becker et al., 2020 ; Hartenfels, 2024 ). Both events would be related with the beginning of first order T–R cycles (sharply transgressions followed by regressions) and anoxic events respectively (Becker, 1993b ; Sandberg et al., 2002 ; Becker et al., 2020 ). In the Compte section the main lithology of the Late Frasnian consists of nodular and bedded limestones and, thus, differs with the typical Kellwasser black shales facies from Euramerica and Gondwana (Schindler, 1990 ; Ziegler and Sandberg, 1990 ; Becker and House, 1994 ; Lazreq, 1999 ; Gereke et al., 2014 ). Slightly above the base of FZ13b subzone in the Compte section (Bed 89, Fig. 3 ), the change from Palmatolepis – Polygnathus to Polygnathus – Palmatolepis biofacies would suggest a local regressive trend, which may be referred to as the linguiformis regression that is placed before the Upper Kellwasser Event and is recorded worldwide (Sandberg et al., 2002 ; Zhang et al., 2019 ). This polygnathid increase recorded during the linguiformis regression is similar to the augment observed in different sections from South China (Huang and Gong, 2016 ; Chang et al., 2017 ; Zhang et al., 2019 ). At the top of FZ13b the transgressive trend identified by a peak of palmatolepids (top of Bed 91, Fig. 3 ) could be interpreted as a local Event, close in time to the Upper Kellwasser Global Event. Polygnathus decorosus becomes extinct in this interval and Polygnathus lodinensis , Palmatolepis boogaardi , Ancyrognathus asymmetricus , Polygnathus webbi , Palmatolepis juntianensis and Ancyrognathus amana are extinct in the base of FZ13c in Compte section (sample CP/92a). Typical Frasnian conodonts become extinct at the top of FZ13c subzone (upper part of Bed 92): Ancyrodella curvata , Palmatolepis winchelli , Palmatolepis bogartensis and Ancyrognathus asymmetricus . The extinction of many conodont taxa and the rise of icriodids indicating regressive trend, would indicate the Upper Kellwasser Event at the top of FZ13c. On the other hand, various authors suggest that the Upper Kellwasser interval is recorded earlier, slightly below the base of the Famennian. In South China the Upper Kellwasser Event might be formed by a transgressive trend positioned between the top of FZ13b and FZ13c; it was identified by microfacies analysis and high abundance of Palmatolepis (Zhang, 2019). Subsequently, Farabegoli et al. ( 2023 ) divided the Upper Kellwasser extinction events in two phases. In the first phase several species of Palmatolepis , Polygnathus , Ancyrodella and Ancyrognathus became extinct at the top of FZ13b. In the second phase all Ancyrodella and “manticolepids” Palmatolepis , except Palmatolepis ultima became extinct at the top of FZ13c. Nehden Event. The Nehden Event is a long–term adaptative radiation process, correlated with a regressive trend rather than an extinction Global Event (Becker, 1993b ; House, 2002 ). Walliser ( 1985 ; 1996 ) proposed the name Cheiloceras Event, due to the typical record of cheiloceratids ammonoids. During this Event, besides this radiation, other organisms as rhynchonellids brachiopods and palmatolepid conodonts proliferates (Becker, 1993a , b ; Huang et al., 2024 ). This conodont bloom is under discussion, either as a gradual biodiversification (Schülke, 1995 , 1999 ; House, 2002 ; Huang et al., 2024 ), or an abrupt biodiversification event (Schülke and Popp, 2005 ; Girard et al., 2014 ). The sedimentary expression is characterized by black shales related with the transgressive trend in Western Europe (Becker, 1993b ; Becker et al., 2016 ). However, and due to is limitation to local areas (Huang et al., 2024 ), the timing, impact order and magnitude of this event is still unclear. The duration of this event is within the Palmatolepis termini and Palmatolepis gl. prima zones (Becker et al., 2020 ) with a maximum flooding related with a maximum of pelagic black shales sedimentation in the top of the Palmatolepis termini Zone and the Palmatolepis gl. prima Zone (Becker et al., 2016 ; Hartenfels, 2024 ). In the Compte section, there are neither evidence of “Nehden black shales” nor ammonoids radiation. However, the conodont data suggest a prolonged transgressive trend during the Palmatolepis crepida – Palmatolepis gl. prima zones interval with the proliferation of palmatolepid biofacies alternating with Palmatolepis – Icriodus biofacies in the Palmatolepis gl. prima Zone. A bloom of Palmatolepis (98%) is recorded at the top of the Palmatolepis gl. prima Zone (Bed 104, sample CP/104b, Fig. 3 ), which suggests a maximum flooding of the Nehden Event. This transgressive trend interval suggests the extension of the Nehden Event up to the top of Palmatolepis gl. prima Zone in the Compte section. Similar timing is observed in the Lali section in South China with a peak of palmatolepids in the upper part of the Palmatolepis gl. prima Zone (Zhang et al., 2019 , Fig. 7). Different timing is documented in the Yangdi section, South China, which is subdivided into two Nehden Events (Huang et al., 2024 ), located earlier, within the Palmatolepis mint. minuta Zone and among Palmatolepis termini – Palmatolepis gl. pectinata zones respectively. Condroz events. After the Nehden transgressive Event, two abrupt regressive events widely recorded called Condroz Events, took place within the Palmatolepis rhomboidea and Palmatolepis gr. gracilis zones (Becker, 1993b ; Schülke and Popp, 2005 ; Becker et al., 2020 ). These events started coinciding with the disappearance of the Cheiloceras shales (Schülke and Popp, 2005 ) and the global regressive tendency. a Rich conodont fauna, specially Palmatolepis rhomboidea and a short regressive trend (Hartenfels et al., 2013 ; Hartenfels, 2024 ) occur between these two regressive events, within the Palmatolepis gr. gracilis Zone. However, these events do not have a significant impact on conodonts (Hartenfels, 2024 ). The change of the Palmatolepis – Polygnathus to the Icriodus – Palmatolepis biofacies in Bed 109 (sample CP/109b, Fig. 3 ), within the Palmatolepis rhomboidea Zone, suggests an abrupt regressive trend that can be aligned with the Lower Condroz Event. We accept that the Icriodus – Palmatolepis biofacies is shallower than the Palmatolepis – Icriodus sensu Corradini ( 1998 ). During the lower part of the Palmatolepis gr. gracilis Zone, a bloom of Palmatolepis rhomboidea in the Compte section (Barrera-Lahoz et al., 2025 , Table 2) similar to the one in Tafilalt (Hartenfels et al., 2013 ) is recorded. After the Lower Condroz Event, a transgressive trend is recognized by the appearance of the Palmatolepis biofacies in the transition from the Palmatolepis rhomboidea to Pal. gr. gracilis zones. The Upper Condroz Event is recognized in the Compte section at the base of Bed 113 (Fig. 3 ), within the Palmatolepis gr. gracilis Zone, corresponding with a short income of the Polygnathus – Palmatolepis biofacies within the overall Palmatolepis-Polygnathus biofacies. 6 Conclusions The Compte section yields a rich conodont fauna showing different faunal events and compositional changes. Five conodont biofacies are recognized in the Compte section: Palmatolepis , Palmatolepis – Polygnathus , Polygnathus – Palmatolepis , Palmatolepis – Icriodus and Icriodus – Palmatolepis ; they provide essential information about faunistic fluctuations and can be used as a proxy for recognizing eustatic changes. The Palmatolepis biofacies is mainly located in the FZ13b subzone, the Palmatolepis crepida to the Palmatolepis termini zones, the lower and upper parts of the Palmatolepis gl. prima Zone, the base of the Palmatolepis rhomboidea Zone, the Palmatolepis rhomboidea – gr. gracilis zones transition and in the Palmatolepis mg. marginifera Zone. The Palmatolepis – Polygnathus biofacies is recorded mainly in the FZ13b and FZ13c subzones, the Palmatolepis rhomboidea Zone and the Palmatolepis gr. gracilis Zone. The Polygnathus – Palmatolepis biofacies is placed within the FZ13a and FZ13b subzones, the Palmatolepis gl. pectinata and the Palmatolepis gr. gracilis zones. The Icriodus – Palmatolepis biofacies is set at the top of the FZ13c subzone, within the Palmatolepis del. platys , the Palmatolepis gl. prima and at the base of the Palmatolepis gl. pectinata . The new Icriodus – Palmatolepis biofacies, is pinpointed by three sharply peaks of Icriodus in the Palmatolepis mint. minuta , Palmatolepis gl. pectinata and Palmatolepis rhomboidea zones. Comparing the distribution in the Compte section with other regions, the conodont biofacies distribution shows similarities and discrepancies: during the FZ13a–b interval, polygnathids are also abundant in different sections in Poland, Italy and China (Matyja, 1993 ; Zhang et al., 2019 ; Farabegoli et al., 2023 ). The increase in the abundance of icriodids and ancyrodellids is also recorded in these sections as well as in the Compte section. The F/F boundary is characterized by a peak of Icriodus related with a maximum sea–level fall. However, and because of the high condensation, the first Famennian conodont zone identified in the Compte section is the Palmatolepis del. platys . The high proportion of Icriodus through the Palmatolepis del. platys – mint. minuta interval is comparable with the records in different European, African and Asian sections. However, the relative abundance of icriodids during the Palmatolepis crepida – termini zones interval in Europe, contrasts with the dominant pelagic Palmatolepis biofacies in the Compte section. Another icriodid peaks are reported in the Palmatolepis gl. pectinata and Palmatolepis rhomboidea zones. Then, the dominance of palmatolepids during the Palmatolepis mg. marginifera Zone is broadly similar within the different regions. The interpretation of the conodont biofacies allows recognition of possible eustatic trends and Global Events. During the end of the Frasnian, a regressive trend is recorded at the base of FZ13b that might be referred to the linguiformis regression. The Upper Kellwasser Event is located in the upper part of the Comabella Fm. (Bed 91) in FZ13c subzone by the extinction of different Frasnian conodonts and the regressive trend at the F–F boundary The Nehden adaptative Event can be located during the Palmatolepis termini – Palmatolepis gl. prima zones with a maximum flooding at the top of the Palmatolepis gl. prima Zone. Within the La Mena Fm., the Condroz Events are recognized by two marked regressive trends pointed by conodont biofacies changes. Declarations Corresponding author Héctor BARRERA-LAHOZ. [email protected] Compliance with ethical standards Conflict of interest: The authors declare that they have no conflict of interest. Funding J. C-L is supported by Maria Zambrano Grant (MIU Next Generation EU, ZA21-005) and José Castillejo Fellowship (MICCIN-MIU, CAS22/00148). H. B-L is supported by Sociedad Española de Paleontología. J. C-L is supported by UCM Research Grant PR 12/24-31569. Acknowledgements This work is supported by the UCM Research Grant PR 12/24-31569. J. C-L is supported by Maria Zambrano Grant (MIU Next Generation EU, ZA21-005) and José Castillejo Fellowship (MICCIN-MIU, CAS22/00148). H. B-L is supported by Sociedad Española de Paleontología. This report represents a contribution to the Project IGCP-652 of UNESCO and, in addition, it conforms a contribution of the research groups GIUV2017-395, GEO-TRANSFER E32 17R and PERIGONDWANA UCM 910231. We also thank the facilities provided by the UNESCO Global Geopark Orígens to carry out our work. Data availability statement All data and materials that provide the research results are available within this article and extended in Barrera-Lahoz et al. ( 2024 ). The conodont remains which support the article data are housed in “Department of Botany and Geology” in University of Valencia, Burjasot, Spain. References Bahrami, A., Parast, A., Boncheva, I., & Yazdi, M. (2020). Late Devonian (Famennian) conodonts from Baqer-Abad section, northeast Isfahan province, Central Iran. Boletín de la Sociedad Geológica Mexicana , 72 (2), A100619. http://dx.doi.org/10.18268/BSGM2020v72n2a100619 Barnolas, A., & Pujalte, V. (2004). Cordillera Pirenaica. Definición, límites y división. In J. A. Vera (Ed.), Geología de España (pp. 233–240). SGE-IGME. Barrera-Lahoz, H., Valenzuela-Ríos, J. I., & Liao, J. C. (2024). Famennian conodont assemblage in the Compte section (Upper Devonian, Central Pyrenees) and its comparison with Eurasian sequences. Spanish Journal of Palaeontology , 39 (1), 33–70. https://doi.org/10.7203/sjp.28695 Barrera-Lahoz, H., Valenzuela-Ríos, J. I., & Liao, J-C. (2025). Lower and middle Famennian (Upper Devonian) conodont biostratigraphy from Compte section (Central Pyrenees, Spain). In A. Munkhjargal, K. Mende, J. Lu, & U. Linnemann (Eds.), Special contributions in honour of Peter Königshof. Palaeobiodiversity and Palaeoenvironments , 105(1). https://doi.org/10.1007/s12549-025-00642-9 Becker, R. T. (1993a). Stratigraphische Gliederung und Ammonoideen-Faunen im Nehdenium (Oberdevon II) von Europa und Nord-Afrika. Courier Forschungsinstitut Senckenberg , 155 , 1–405. Becker, R. T. (1993b). Anoxia, eustatic changes, and Upper Devonian to lowermost Carboniferous global ammonoid diversity. In M. R. House (Ed.), The Ammonoidea: Environment, ecology and evolutionary change . Systematic Association, Special Volume, 47 , 115–163. Becker, R. T., & House, M. R. (1994). Kellwasser Events and goniatite successions in the Devonian of the Montagne Noire with comments on possible causations. Courier Forschungsinstitut Senckenberg , 169 , 45–77. Becker, R. T., & House, M. R. (1997). Sea–level changes in the Upper Devonian of the Canning Basin, western Australia. Courier Forschungsinstitut Senckenberg , 199 , 129–146. Becker, R. T., Hartenfels, S., Helling, S., & Schreiber, G. (2016). The Nehden Goniatite Shale (lower Famennian, Brilon Reef Komplex, NE Rhenish Massif). In R. T. Becker, S. Hartenfels, P. Konigshof, & S. Helling (Eds.). Middle Devonian to Lower Carboniferous stratigraphy, facies, and bioevents in the Rhenish Massif, Germany – an IGCP 596 Guidebook. Münstersche Forschungen zur Geologie und Paläontologie, 108 , 179–195. Becker, R. T., Marshall, J. E. A., Da Silva, A. C., Agterberg, F. P., Gradstein, F. M., & Ogg, J. G. (2020). The Devonian Period. In: Agterberg, F.P., Gradstein, F.M., Ogg, J.G. (Eds.), The Geologic Time Scale (2nd vol. pp. 733–810). Elsevier. https://doi.org/10.1016/B978-0-12-824360-2.00022-X Boersma, K. T. (1973). Devonian and Lower Carboniferous conodont biostratigraphy, Spanish Central Pyrenees. Leidse Geologische Mededelingen , 49 (2), 303–377. Buggisch, W. (1991). The global Frasnian-Famennian» Kellwasser Event «. Geologische Rundschau , 80 , 49–72. https://doi.org/10.1007/BF01828767 Carmichael, S. K., Waters, J. A., Königshof, P., Suttner, T. J., & Kido, E. (2019). Paleogeography and paleoenvironments of the Late Devonian Kellwasser event: A review of its sedimentological and geochemical expression. Global and Planetary Change , 183 , 102984. https://doi.org/10.1016/j.gloplacha.2019.102984 Chang, J., Bai, Z., Sun, Y., Peng, Y., Qin, S., & Shen, B. (2017). High resolution bio-and chemostratigraphic framework at the Frasnian–Famennian boundary: implications for regional stratigraphic correlation between different sedimentary facies in South China. Palaeogeography Palaeoclimatology Palaeoecology , 531 , 108299. https://doi.org/10.1016/j.palaeo.2017.05.019 Corradini, C. (1998). Famennian conodonts from two sections near Villasalto. Giornale di Geologia , seria 3 a , Special Issue . Sardinia Field Trip Guidebook , 60 , 122–135. Corradini, C. (2003). Late Devonian (Famennian) conodonts from the Corona Mizziu Sections near Villasalto (Sardinia, Italy). Palaeontographia Italica , 89 , 65–116. Dreesen, R., & Thorez, J. (1980). Sedimentary environments, conodont biofacies and paleoecology of the Belgian Famennian (Upper Devonian)-an approach. Annales de la Société géologique de Belgique , 103 , 97–110. Farabegoli, E., Perri, M. C., Spalletta, C., Joachimski, M. M., Andrew, A., & Pondrelli, M. (2023). Physical and biological events across the Frasnian-Famennian boundary (Late Devonian) in continuous oxic carbonate successions in the western Tethys (Carnic Alps of Italy and Austria). Bollettino della Società Paleontologica Italiana , 62 (2), 143–217. https://dx.doi.org/10.4435/BSPI.2023.06 Gereke, M., Luppold, F. W., Piecha, M., Schindler, E., & Stoppel, D. (2014). Die Typlokalität der Kellwasser-Horizonte im Oberharz, Deutschland. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften , 145–162. Girard, C., & Renaud, S. (2007). Quantitative conodont-based approaches for correlation of the Late Devonian Kellwasser anoxic events. Palaeogeography Palaeoclimatology Palaeoecology , 250 (1–4), 114–125. https://doi.org/10.1016/j.palaeo.2007.03.007 Girard, C., Klapper, G., & Feist, R. (2005). Subdivision of the terminal Frasnian linguiformis conodont Zone, revision of the correlative interval of Montagne Noire Zone 13, and discussion of stratigraphically significant associated trilobites. Developments in Palaeontology and Stratigraphy , 20 , 181–198. https://doi.org/10.1016/S0920-5446(05)80007-X Girard, C., Cornee, J. J., Corradini, C., Fravalo, A., & Feist, R. (2014). Palaeoenvironmental changes at Col des Tribes (Montagne Noire, France), a reference section for the Famennian of north Gondwana-related areas. Geological Magazine , 151 (5), 864–884. https://doi.org/10.1017/S0016756813000927 Girard, C., Cornee, J. J., Charruault, A. L., Corradini, C., Weyer, D., Bartzsch, K., Joachimski, M., & Feist, R. (2017). Conodont biostratigraphy and palaeoenvironmental trends during the Famennian (Late Devonian) in the Thuringian Buschteich section (Germany). Newsletters on Stratigraphy , 50 (1), 71–89. https://doi.org/10.1127/nos/2016/0318 Girard, C., Cornee, J. J., Joachimski, M. M., Charruault, A. L., Dufour, A. B., & Renaud, S. (2020). Paleogeographic differences in temperature, water depth and conodont biofacies during the Late Devonian. Palaeogeography Palaeoclimatology Palaeoecology , 549 , 108852. https://doi.org/10.1016/j.palaeo.2018.06.046 Hartenfels, S. (2024). Upper Devonian to Mississippian global environmental change and impact on conodonts. Palaeobiodiversity and Palaeoenvironments , 1–54. https://doi.org/10.1007/s12549-024-00622-5 Hartenfels, S., Becker, R. T., Aboussalam, Z. S., Hassani, E., Baider, A., Fischer, L., T., & Stichling, S. (2013). The Upper Devonian at El Khraouia (southern Tafilalt). In R. T. Becker, A. El Hassani, & A. Tahiri (Eds.). International Field Symposium the Devonian and Lower Carboniferous of northern Gondwana. Document de l’Institut Scientifique, Rabat, 27 , 41–50. Hartevelt, J. J. A. (1970). Geology of the upper Segre and Valira valleys, central Pyrenees, Andorra/Spain. Leidse Geologische Mededelingen , 45 (1), 167–236. House, M. R. (2002). Strength, timing, setting and cause of mid-Palaeozoic extinctions. Palaeogeography Palaeoclimatology Palaeoecology , 181 (1–3), 5–25. https://doi.org/10.1016/S0031-0182(01)00471-0 Huang, C., & Gong, Y. (2016). Timing and patterns of the Frasnian–Famennian event: Evidences from high-resolution conodont biostratigraphy and event stratigraphy at the Yangdi section, Guangxi, South China. Palaeogeography Palaeoclimatology Palaeoecology , 448 , 317–338. https://doi.org/10.1016/j.palaeo.2015.10.031 Huang, C., Song, H., Zhai, M., Pu, T., & Han, M. (2024). Timing and pattern of the Devonian Nehden event: Implication for the biotic recovery following the F–F extinction event. Palaeogeography Palaeoclimatology Palaeoecology , 648 , 112276. https://doi.org/10.1016/j.palaeo.2024.112276 Institut Cartogràfic i Geològic de Catalunya (2024, October 28). Mapa Geològic de Catalunya 1:25000 . https://betaportal.icgc.cat/visor/client_utfgrid_geo.html Johnson, J. G., Klapper, G., & Sandberg, C. A. (1985). Devonian eustatic fluctuations in Euramerica. Geological Society of America Bulletin , 96 (5), 567–587. https://doi.org/10.1130/0016-7606(1985)962.0.CO;2 Klapper, G. (1989). The Montagne Noire Frasnian (Upper Devonian) Conodont Succession. In N. J. McMillan, A. F. Embry, & D. J. Glass (Eds.), Devonian of the World. Canadian Society of Petroleum Geologists , Memoir , 14 (III), 449–468 [imprint 1988]. Klapper, G. (2007). Conodont taxonomy and the recognition of the Frasnian/Famennian (Upper Devonian) stage boundary. Stratigraphy , 4 (1), 67–76. Klapper, G., & Kirchgasser, W. T. (2016). Frasnian Late Devonian conodont biostratigraphy in New York: graphic correlation and taxonomy. Journal of Paleontology , 90 (3), 525–554. https://doi.org/10.1017/jpa.2015.70 Lazreq, N. (1992). The upper Devonian of M’rirt (Morocco). Courier Forschungsinstitut Senckenberg , 154 , 107–123. Lazreq, N. (1999). Biostratigraphie des conodontes du Givétien au Famennien du Maroc central – Biofaciès et événement Kellwasser. Courier Forschungsinstitut Senckenberg , 214 , 1–111. Liao, J. C. (2014). Bioestratigrafía con conodontos del givetiense (Devónico Medio) del Pirineo Central (PhD Thesis, Universidad Complutense de Madrid). Liao, J. C., & Valenzuela- Ríos, J. I. (2008). Givetian and early Frasnian conodonts from the Compte section (Middle–Upper Devonian, Spanish Central Pyrenees). Geological Quaterly , 52 (1), 1–18. Liao, J. C., & Valenzuela-Ríos, J. I. (2017). Givetian to Famennian conodonts (Middle–Upper Devonian) at CP section. International Conodont Symposium 4. Progress on Conodont investigation (pp. 99–105). Valencia. Liao, J. C., Königshof, P., Valenzuela-Rios, J. I., & Schindler, E. (2008). Depositional environment interpretation and development of the Renanué section (Upper Eifelian-Lower Frasnian; Pyrenees, N. Spain). Bulletin of Geosciences , 83 , 481–490. https://doi.org/10.3140/bull.geosci.2008.04.481 Lüddecke, F., Hartenfels, S., & Becker, R. T. (2017). Conodont biofacies of a monotonous middle Famennian pelagic carbonate succession (Upper Ballberg Quarry, northern Rhenish Massif). Palaeobiodiversity and Palaeoenvironments , 97 , 591–613. https://doi.org/10.1007/s12549-017-0288-x Martínez-Pérez, C., & Valenzuela-Ríos, J. I. (2014). New Lower Devonian Polygnathids (Conodonta) from the Spanish Central Pyrenees, with comments on the early radiation of the group. Journal of Iberian Geology , 40 (1), 141–155. https://doi.org/10.5209/rev_JIGE.2014.v40.n1.44095 Martínez-Pérez, C., Valenzuela-Ríos, J. I., Navas-Parejo, P., Liao, J. C., & Botella, H. (2011). Emsian (Lower Devonian) Polygnathids (Conodont) succession in the Spanish Central Pyrenees. Journal of Iberian Geology , 37 (1), 45–64. https://doi.org/10.5209/rev_JIGE.2011.v37.n1.4 Matyja, H. (1993). Upper Devonian of Western Pomerania. Acta Geologica Polonica , 43 (1/2), 27–94. Matyja, H., & Narkiewicz, M. (1992). Conodont biofacies succession near the Frasnian/Famennian boundary: some Polish examples. Courier Forschungsinstitut Senckenberg , 154 , 125–147. McGhee, G. R. (2013). When the Invasion of Land Failed: The Legacy of the Devonian Extinctions . Columbia University. McGhee, G. R., Clapham, M. E., Sheehan, P. M., Bottjer, D. J., & Droser, M. L. (2013). A new ecological-severity ranking of major Phanerozoic biodiversity crises. Palaeogeography Palaeoclimatology Palaeoecology , 370 , 260–270. https://doi.org/10.1016/j.palaeo.2012.12.019 Mey, P. H. W. (1967a). The geology of the upper Ribagorzana and Baliera valleys, Central Pyrenees, Spain. Leidse Geologische Mededelingen , 41 , 153–220. Mey, P. H. W. (1967b). Evolution of the Pyrenean Basins during the Late Paleozoic. International Symposium on the Devonian System (pp. 1157–1166). Calgary. Morrow, J. (2000). Shelf-to-Basin Lithofacies and Conodont Paleoecology across Frasian–Famennian (F–F, mid–Late Devonian) Boundary, Central Great Basin (Western U.S.A). Courier Forschungsinstitut Senckenberg , 219 , 1–57. Sánchez de Posada, L. C., Sanz-López, J., & Gozalo, R. (2008). Ostracod and conodont faunal changes across the Frasnian–Famennian (Devonian) boundary at Els Castells, Spanish central Pyrenees. Revue de Micropaléontologie , 51 (3), 205–219. https://doi.org/10.1016/j.revmic.2007.06.001 Sandberg, C. A. (1976). Conodont biofacies of the Late Devonian Polygnathus styriacus Zone in western United States. In C.R. Barner (Ed.), Conodont paleoecology. Geological Association of Canada , Special Paper , 15 , 171–186. Sandberg, C. A., & Dreesen, R. (1984). Late Devonian icriodontid biofacies models and alternate shallow-water conodont zonation. In D.L. Clark (Ed.), Conodont biofacies and provincialism. Geological Society of America , Special Papers , 196 , 143–179. Sandberg, C. A., Ziegler, W., Dreesen, R., & Buttler, J. L. (1988). Late Frasnian mass extinction: conodont event stratigraphy, global changes, and possible causes. In W. Ziegler (Ed.), 1st International Conodont Conference and 5th European Conodont Symposium (ECOS V) Contributions 1. Courier Forschungsinstitut Senckenberg , 102 , 263–307. Sandberg, C. A., Hasenmueller, N. R., & Rexroad, C. B. (1994). Conodont biochronology, biostratigraphy, and biofacies of Upper Devonian part of New Albany Shale, Indiana. Courier Forschungsinstitut Senckenberg , 168 , 227–253. Sandberg, C., Morrow, J. R., & Ziegler, W. (2002). Late Devonian sea-level changes, catastrophic events, and mass extinctions. Geological Society of America Special Papers , 356 , 473–487. https://doi.org/10.1130/0-8137-2356-6.473 Sanz-López, J., García-López, S., & Montesinos López, J. R. (1999). Conodontos del Frasniense superior y Fameniense inferior de la Formación Cardaño (Unidad del Cildar-Montó, Dominio Palentino, Zona Cantábrica). Spanish Journal of Palaeontology , 14 (1), 25–35. https://doi.org/10.7203/sjp.22779 Savoy, L. E., & Harris, A. G. (1993). Conodont biofacies in a ramp to basin setting (latest Devonian and earliest Carboniferous) in the Rocky Mountains of southernmost Canada and northern Montana. U. S. Geological Survey . Open-File Report , 93–184, 1–37. Schmidt, H., & Göttingen (1931). math–phys Kl , 3 (5, 1–85. Schindler, E. (1990). Die Kellwasser-Krise. Göttinger Arbeiten zur Geologie und Paläontologie , 46 , 1–115. Schülke, I. (1995). Evolutive Prozesse bei Palmatolepis in der fruhen Famenne-Stufe (Conodonta, Ober-Devon). Göttinger Arbeiten zur Geologie und Paläontologie , 67 , 1–108. Schülke, I. (1999). Conodont multielement reconstruction from the Early Famennian (Late Devonian) of the Montagne Noire (Southern France). Geologica et Palaeontologica , 3 , 1–123. Schülke, I. (2003). Famennian conodont biodiversity cycles. Courier Forschungsinstitut Senckenberg , 242 , 225–238. Schülke, I., & Popp, A. (2005). Microfacies development, sea-level change, and conodont stratigraphy of Famennian mid-to deep platform deposits of the Beringhauser Tunnel section (Rheinisches Schiefergebirge, Germany). Facies , 50 , 647–664. https://doi.org/10.1007/s10347-004-0041-6 Seddon, G. (1970). Frasnian conodonts from the Sadler Ridge-Bugle Gap area, Canning Basin, Western Australia. Journal of the Geological Society of Australia , 10 , 723–753. Seddon, G., & Sweet, W. C. (1971). An ecologic model for conodonts. Journal of Paleontology , 45 (5), 869–880. Silvério, G. G., Valenzuela-Ríos, J. I., & Liao, J. C. (2021). Upper Frasnian and Lower Famennian (Upper Devonian) conodonts of the Compte section (Spanish Central Pyrenees). Spanish Journal of Palaeontology , 36 (2), 205–220. https://doi.org/10.7203/sjp.36.2.21950 Spalletta, C., Perri, M. C., Over, D. J., & Corradini, C. (2017). Famennian (Upper Devonian) conodont zonation: revised global standard. Bulletin of Geosciences , 92 (1), 31–57. https://doi.org/10.3140/bull.geosci.1623 Suttner, T. J., Kido, E., Ariunchimeg, Y., Sersmaa, G., Waters, J. A., Carmichael, S. K., Batchelor, C. J., Ariuntogos, M., Hušková, A., Slavík, L., Valenzuela-Ríos, J. I., Liao, J. C., & Gatovsky, Y. A. (2020). Conodonts from Late Devonian Island arc settings (Baruunhuurai Terrane, western Mongolia). Palaeogeography Palaeoclimatology Palaeoecology , 549 , 109099. https://doi.org/10.1016/j.palaeo.2019.03.001 Tagarieva, R. C. (2013). Conodont biodiversity of the Frasnian-Famennian boundary interval (Upper Devonian) in the Southern Urals. Bulletin of Geosciences , 88 (2), 297–314. https://doi.org/10.3140/bull.geosci.1344 Valenzuela-Ríos, J. I., & Liao, J. C. (2006). Annotations to Devonian Correlation Table, R 357–360 di-ds 06: Spanish Central Pyrenees, southern part. Senckenbergiana lethaea , 86 , 105–107. https://doi.org/10.1007/BF03043640 Valenzuela-Ríos, J. I., Chen, L., Martínez-Pérez, J. C., Castelló, C., V., & Botella, H. (2005). Datos preliminares sobre los conodontos y restos de peces del Lochkoviense y ¿Praguiense? (Devónico Inferior) de Compte-I (Valle del Noguera Pallaresa, Pirineos). In: J.I. Valenzuela-Ríos; J.A. Gámez y E. Liñán (Eds.), Memorias de las VIII Jornadas Aragonesas de Paleontología: La cooperación Internacional en la Paleontología española. Homenaje al Profesor Peter Carls , 123–136. Valenzuela-Ríos, J. I., Slavík, L., Liao, J. C., Calvo, H., Hušková, A., & Chadimová, L. (2015). The middle and upper Lochkovian (Lower Devonian) conodont successions in key peri‐Gondwana localities (Spanish Central Pyrenees and Prague Synform) and their relevance for global correlations. Terra Nova , 27 (6), 409–415. https://doi.org/10.1111/ter.12172 Walliser, O. H. (1985). Natural boundaries and Commission boundaries in the Devonian. Courier Forschungsinstitut Senckenberg , 75 , 401–408. Walliser, O. H. (1996). Global Events in the Devonian and Carboniferous. In O. H. Walliser (Ed.), Global Events and Event Stratigraphy in the Phanerozoic . Springer. https://doi.org/10.1007/978-3-642-79634-0_11 Yazdi, M. (1999). Late Devonian–Carboniferous conodonts from Eastern Iran. Rivista Italiana di Paleontologia e Stratigrafia , 105 (2), 167–200. Zhang, X. S., Over, D. J., Ma, K., & Gong, Y. (2019). Upper Devonian conodont zonation, sea-level changes and bio-events in offshore carbonate facies Lali section, South China. Palaeogeography Palaeoclimatology Palaeoecology , 531 , 109219. https://doi.org/10.1016/j.palaeo.2019.05.041 Ziegler, W. (1959). Conodonten aus Devon und Karbon Südwesteuropas und Bemerkungen zur bretonischen Faltung (Montagne Noire, Massiv Mounthoumet, Span. Pyrenäen). Neus Jahrbuch für Geologie und Paläeontologie Monatshefte , 7 , 289–309. Ziegler, W., & Sandberg, C. A. (1990). The Late Devonian Standard Conodont Zonation. Courier Forschungsinstitut Senckenberg , 121 , 1–115. Zwart, H. J. (1979). The geology of the Central Pyrenees. Leidse Geologische Mededelingen , 50 (1), 1–74. Tables Table 1 is available in the Supplementary Files section. Supplementary Files Tab.1.docx Table. 1 Biostratigraphic distribution, samples weight and genera content and percentages of Beds 84 to 120 in the section Compte. Pa : Palmatolepis ; Po : Polygnathus ; Ic : Icriodus ; Ac : Ancyrodella ; Ag : Ancyrognathus ; Pe : Pelekysgnathus ; Me : Mehlina ; An : Ancyrodella group ( Ancyrodella + Ancyrognathus ). Green color in sample names represents Comabella Formation; red color La Mena Formation and blue colour Barousse Formation. Cite Share Download PDF Status: Published Journal Publication published 22 Apr, 2026 Read the published version in Journal of Iberian Geology → Version 1 posted Editor invited by journal 16 Oct, 2025 Reviewers agreed at journal 18 May, 2025 Reviewers invited by journal 15 May, 2025 Editor assigned by journal 11 Apr, 2025 First submitted to journal 09 Apr, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6413435","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":457229573,"identity":"ca44a99e-05bd-449c-8526-4483c02b581c","order_by":0,"name":"Héctor Barrera-Lahoz","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYBACfvbmgw8+VNgwMDATq0Wy51iy4YwzaSRoMZiRYybN23KYBIcZSOSYSfA2nE/czs7+8HMFg409QS3mPM+KLSR33E7c2cyQLHmGIS2xgZAWy/bkjTcMz9xO3HCY4YBkA8PhBMIOO5BgIJHYdg6ohbH5ZwPDf8IOMziRYiRxsO0AUAszG9CWA4wEHQYO5IYzycYbDrOxWTYYJBP2CygqH/+psJPdcP7445sNFXaEHYbuTlI1jIJRMApGwSjACgAPNEJSVSPZLgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0001-7003-8336","institution":"Universidad de Zaragoza","correspondingAuthor":true,"prefix":"","firstName":"Héctor","middleName":"","lastName":"Barrera-Lahoz","suffix":""},{"id":457229574,"identity":"5b7529de-60f5-43a5-89d6-1c6ce63f643a","order_by":1,"name":"José Ignacio Valenzuela-Ríos","email":"","orcid":"","institution":"Universidad de Valencia: Universitat de Valencia","correspondingAuthor":false,"prefix":"","firstName":"José","middleName":"Ignacio","lastName":"Valenzuela-Ríos","suffix":""},{"id":457229575,"identity":"da3c5eea-e10a-4237-bd5a-6cbd6887f0f4","order_by":2,"name":"Jau‑Chyn Liao","email":"","orcid":"","institution":"Universidad Complutense de Madrid","correspondingAuthor":false,"prefix":"","firstName":"Jau‑Chyn","middleName":"","lastName":"Liao","suffix":""}],"badges":[],"createdAt":"2025-04-09 15:44:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6413435/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6413435/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s41513-026-00335-y","type":"published","date":"2026-04-22T15:57:34+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83070499,"identity":"db16d562-c345-4eba-b8d0-bb8eedac7e11","added_by":"auto","created_at":"2025-05-19 16:29:48","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":557514,"visible":true,"origin":"","legend":"\u003cp\u003ea. Schematic tectonic and geologic map of the Pyrenees (modified from Barnolas \u0026amp; Pujalte, 2004). b. Southern facies–area scheme in the Central Pyrenees area (modified from Valenzuela-Ríos et al., 2015). c. Geological map of the Gerri de la Sal– La Guàrdia d’Ares zone (modified from Institut Cartogràfic I Geològic de Catalunya, 2024). \u003cstrong\u003eCP: \u003c/strong\u003eCompte section; \u003cstrong\u003eEC: \u003c/strong\u003eEls Castells section.\u003c/p\u003e","description":"","filename":"Fig1..png","url":"https://assets-eu.researchsquare.com/files/rs-6413435/v1/64c474735682b926bf578232.png"},{"id":83070504,"identity":"78219c5f-2eff-4b75-97f9-b6d21c48e1db","added_by":"auto","created_at":"2025-05-19 16:29:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":842684,"visible":true,"origin":"","legend":"\u003cp\u003eChrono and biostratigraphic interpretation with stratigraphic distribution of the main conodont taxa in the Compte section from Bed 84 to Bed 120. \u003cem\u003ePa.\u003c/em\u003e: \u003cem\u003ePalmatolepis\u003c/em\u003e; \u003cem\u003eP.\u003c/em\u003e: \u003cem\u003ePolygnathus\u003c/em\u003e; \u003cem\u003eIc.\u003c/em\u003e: \u003cem\u003eIcriodus\u003c/em\u003e; \u003cem\u003eAc.\u003c/em\u003e: \u003cem\u003eAncyrodella\u003c/em\u003e; \u003cem\u003eAg.\u003c/em\u003e: \u003cem\u003eAncyrognathus\u003c/em\u003e; \u003cem\u003eMe.\u003c/em\u003e: \u003cem\u003eMehlina\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-6413435/v1/52bd41f8b4fbbeec75d806e0.png"},{"id":83071755,"identity":"2d613654-e3da-4b7a-a4fe-cc5b4331f58a","added_by":"auto","created_at":"2025-05-19 16:45:48","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":512998,"visible":true,"origin":"","legend":"\u003cp\u003eConodont biofacies distribution in the Compte section: percentages of numerical abundance of conodont genera, blue: \u003cem\u003ePalmatolepis\u003c/em\u003e; green: \u003cem\u003ePolygnathus\u003c/em\u003e; red: \u003cem\u003eIcriodus\u003c/em\u003e; pink: Ancyrodellids (\u003cem\u003eAncyrodella\u003c/em\u003e+\u003cem\u003eAncyrognathus\u003c/em\u003e); orange: \u003cem\u003eMehlina\u003c/em\u003e and black: \u003cem\u003ePelekysgnathus\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Fig.31.png","url":"https://assets-eu.researchsquare.com/files/rs-6413435/v1/6ff084279f94419b19492ad2.png"},{"id":83070503,"identity":"8bb5fa83-fecf-42df-b5a4-980de85f2e2c","added_by":"auto","created_at":"2025-05-19 16:29:48","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":111192,"visible":true,"origin":"","legend":"\u003cp\u003ePaleogeographic map during the Frasnian–Famennian transition (modified from Carmichael et al., 2019). 1: Pyrenees, Spain; 2: Cantabrian, Spain; 3: Montagne Noire, France; 4: Sardinia, Italia; 5: Carnic Alps, Italia–Austria; 6: Central Massif, Atlas, Morocco; 7: Thuringia, Germany; 8: Western Pomerania, Poland; 9: Holy Cross Mountains, Poland; 10: South Urals, Russia; 11: Central Iran; 12: Baruunhuurai Terrane, Mongolia; 13: Guangxi region, China; 14: Indiana, USA; Central basin, USA.\u003c/p\u003e","description":"","filename":"Fig.4.png","url":"https://assets-eu.researchsquare.com/files/rs-6413435/v1/b9713e776bef8fe707ec92b8.png"},{"id":107927688,"identity":"0824d723-62d2-48b5-a975-e2929ee24b86","added_by":"auto","created_at":"2026-04-27 16:01:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2893782,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6413435/v1/49e2695d-ca2e-487e-b47e-4b62194e42bf.pdf"},{"id":83070497,"identity":"3ebfb614-e12c-49b4-a8f3-8750d2e88de2","added_by":"auto","created_at":"2025-05-19 16:29:48","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":36944,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTable. 1 \u003c/strong\u003eBiostratigraphic distribution, samples weight and genera content and percentages of Beds 84 to 120 in the section Compte. \u003cem\u003ePa\u003c/em\u003e: \u003cem\u003ePalmatolepis\u003c/em\u003e; \u003cem\u003ePo\u003c/em\u003e: \u003cem\u003ePolygnathus\u003c/em\u003e; \u003cem\u003eIc\u003c/em\u003e: \u003cem\u003eIcriodus\u003c/em\u003e; \u003cem\u003eAc\u003c/em\u003e: \u003cem\u003eAncyrodella\u003c/em\u003e; \u003cem\u003eAg\u003c/em\u003e: \u003cem\u003eAncyrognathus\u003c/em\u003e; \u003cem\u003ePe\u003c/em\u003e: \u003cem\u003ePelekysgnathus\u003c/em\u003e; \u003cem\u003eMe\u003c/em\u003e: \u003cem\u003eMehlina\u003c/em\u003e; \u003cem\u003eAn\u003c/em\u003e: \u003cem\u003eAncyrodella group \u003c/em\u003e(\u003cem\u003eAncyrodella\u003c/em\u003e+\u003cem\u003eAncyrognathus\u003c/em\u003e). Green color in sample names represents Comabella Formation; red color La Mena Formation and blue colour Barousse Formation.\u003c/p\u003e","description":"","filename":"Tab.1.docx","url":"https://assets-eu.researchsquare.com/files/rs-6413435/v1/b79d086388dd2ee5361a878c.docx"}],"financialInterests":"","formattedTitle":"Frasnian–Famennian (Upper Devonian) conodont biofacies and Global Events in the Compte section (Central Pyrenees, Spain.)","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eDuring the Upper Devonian Frasnian\u0026ndash;Famennian transition (F/F) the conodont biodiversity experimented significant changes, including the end Frasnian mass extinction (McGhee et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2013\u003c/span\u003e); which was one of the big five greatest extinctions in life\u0026rsquo;s history with substantial biodiversity fluctuations (McGhee, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; McGhee et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). This mass extinction is recorded into two Global Bioevents named Lower and Upper Kellwasser. They are located in the uppermost Frasnian zone, FZ13, (Becker et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). This extinction affected the conodont diversity in different ways: \u003cem\u003eAncyrodella\u003c/em\u003e became extinct, \u003cem\u003ePalmatolepis\u003c/em\u003e was reduced dramatically to one taxon (\u003cem\u003ePalmatolepis ultima\u003c/em\u003e), whereas \u003cem\u003eIcriodus\u003c/em\u003e, \u003cem\u003ePolygnathus\u003c/em\u003e and \u003cem\u003eAncyrognathus\u003c/em\u003e were not widely reduced (Sandberg et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1988\u003c/span\u003e). The Kellwasser events are recorded worldwide on the basis of their lithological expression, which is generally documented as black shales related to anoxic phases (Becker, 1993; Walliser, \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Carmichael et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) and sea level changes (Sandberg et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Sandberg et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2002\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAfter the Kellwasser crisis, the conodont fauna gradually recovers the diversity through the lower Famennian. This recuperation is associated with a sea\u0026ndash;level rise and recorded as black shale facies around Euramerica, Africa and Australia (Becker \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1993a\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003eb\u003c/span\u003e; Becker and House \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Sch\u0026uuml;lke and Popp \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Becker et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2016\u003c/span\u003e); this \u0026ldquo;faunal bloom\u0026rdquo; associated to a transgression is called Nehden Event. Nevertheless, timing, evolution rates and magnitude of its influence are still uncertain (Huang et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Following the Nehden Event, another minor (third order) Global Event took place at the top of the lower Famennian interval, the Condroz Event. This event is widely recorded and related with two regressive pulses (Walliser, \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Becker and House, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Sch\u0026uuml;lke and Popp \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the Pyrenees, first studies focused in general stratigraphical and biostratigraphical features of Devonian rocks (Schmidt, \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e1931\u003c/span\u003e; Ziegler, \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e1959\u003c/span\u003e; Mey, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e1967a\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003eb\u003c/span\u003e; Boersma, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1973\u003c/span\u003e; Zwart, \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e1979\u003c/span\u003e). Pioneers works on high\u0026ndash;resolution biostratigraphy were carried out in the Central Pyrenees area (Liao and Valenzuela-R\u0026iacute;os, 2008; 2013; Mart\u0026iacute;nez-P\u0026eacute;rez and Valenzuela-R\u0026iacute;os, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2014\u003c/span\u003e Mart\u0026iacute;nez-P\u0026eacute;rez et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Gouwy et al., 2013; Valenzuela-R\u0026iacute;os and Liao, 2012; 2024; Valenzuela-R\u0026iacute;os et al., \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Silv\u0026eacute;rio et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Slav\u0026iacute;k et al., 2016), whereas detailed studies on Devonian conodont biofacies are scarce (S\u0026aacute;nchez de Posada et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Liao et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Liao, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Further, upper Frasnian\u0026ndash;lower Famennian Global Events are not studied in detail so far, except in Castells area (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e1\u003c/span\u003ec), (S\u0026aacute;nchez de Posada et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eConodont biofacies provide essential information about ecological environments and water depth (Seddon and Sweet, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e1971\u003c/span\u003e; Sandberg, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1976\u003c/span\u003e). The relative proportions of conodont genera define different assemblages (biofacies) that can be used as a paleobathymetry proxies and its variation through time allows identification of possible sea\u0026ndash;level changes (Seddon and Sweet, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e1971\u003c/span\u003e; Sandberg, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1976\u003c/span\u003e; Sandberg and Dreesen, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e1984\u003c/span\u003e; Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Additionally, conodont biofacies can be a relevant tool as a palaeoenvitonmental proxy in lithological monotonous section with higher precision than lithofacies analysis (L\u0026uuml;ddecke et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe Central Pyrenees area has numerous, discontinuous, and partial Devonian outcrops. One of them, the Compte section, represents an exception as it exhibits an almost complete Devonian sequence and numerous works on Lower, Middle and recently Upper Devonian biostratigraphy have been published (Valenzuela-R\u0026iacute;os et al., \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2005\u003c/span\u003e, \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Liao and Valenzuela-R\u0026iacute;os, 2008; Mart\u0026iacute;nez\u0026ndash;P\u0026eacute;rez et al., 2011; Mart\u0026iacute;nez-P\u0026eacute;rez and Valenzuela-R\u0026iacute;os, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Silv\u0026eacute;rio et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Barrera-Lahoz et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Valenzuela-R\u0026iacute;os and Liao, 2012). Thus, the main goals of this study are: to identify and characterize the conodont biofacies within the upper Frasnian to middle Famennian in the Compte section, and through the interpretation of these biofacies, identify the possible eustatic trends and tentatively recognize the position of the Upper Kellwasser, Nehden and Condroz Global Events in this section.\u003c/p\u003e"},{"header":"2 Geological setting, material provenance and methods","content":"\u003cp\u003eThe Compte section is located in the Spanish Central Pyrenees area, which belongs to the Axial zone of the Pyrenean Range (NE Spain) (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e1\u003c/span\u003ea\u0026ndash;b). Devonian rocks in the Central Pyrenees area developed in different environments resulting in a complex stratigraphical scheme, which chiefly consists of four main facies\u0026ndash;area: North Pyrenean, Northern, Central and Southern (Mey, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e1967a\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003eb\u003c/span\u003e; Hartevelt, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1970\u003c/span\u003e). Furthermore, the Southern facies\u0026ndash;area were subdivided in four subfacies\u0026ndash;area: Renanu\u0026eacute;, Sierra Negra, Baliera and Compte (Mey, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e1967a\u003c/span\u003e; Zwart, \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e1979\u003c/span\u003e; Valenzuela R\u0026iacute;os and Liao, 2006). The Compte section belongs to the latter subfacies\u0026ndash;area. The Compte section exhibits mainly limestone and shale from Lower Devonian to Carboniferous. The Upper Devonian consists of three stratiraphical units: Comabella, La Mena and Barousse Formations. The Comabella Fm. is dated as Givetian to lower Famennian age (Liao and Valenzuela-R\u0026iacute;os, 2008; Silv\u0026eacute;rio et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Barrera-Lahoz et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) and is composed of alternating nodular and bedded, and massive limestones. The La Mena Fm. is dated as lower\u0026ndash;middle Famennian (Barrera-Lahoz et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) and is composed of red griotte nodular limestones and intercalated bedded limestones. The Barousse Fm. ranges from middle Famennian to Tournaisian (Boersma, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1973\u003c/span\u003e; Barrera-Lahoz, 2025) and is composed of nodular and bedded limestones. The main Upper Devonian paleoenvironments of these formations are related with pelagic marine outer platform ramp and hemipelagic condensed carbonate ramp (Liao and Valenzuela-R\u0026iacute;os, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe Compte section is located between Gerri de la Sal and Sort localities (L\u0026eacute;rida, Spain), 2 km north of the former (42\u0026deg;20'14.2\"N, 1\u0026deg;04'04.5\"E) at the right bank of the Noguera Pallaresa river. (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e1\u003c/span\u003eb\u0026ndash;c)\u003c/p\u003e \u003cp\u003eMost of the analyzed material comes Barrera-Lahoz et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2024\u003c/span\u003e, (Comabella, La Mena and Barousse Fms., Beds 98\u0026ndash;120). Additionally, we revisited the published and unpublished material of Silv\u0026eacute;rio et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e (Comabella Fm., Beds 84\u0026ndash;97).\u003c/p\u003e \u003cp\u003eThe stratigraphic section analyzed herein is 12.73 m thick and comprises the three cited geological units: Comabella Fm. (Beds 84\u0026ndash;105), La Mena Fm. (Beds 106\u0026ndash;116) and Barousse Fm. (Beds 117\u0026ndash;120). 74 limestone samples were taken in different field campaigns, weighting between 0.025 kg and 3 kg, with a weight average of 0.5\u0026ndash;1 kg (Table\u0026nbsp;1). Almost each bed was sampled and several beds were subdivided taking different samples in the same bed. The rock samples were dissolved in acetic and formic acids (~\u0026thinsp;7\u0026ndash;8%) in 5\u0026ndash;10 liters of water solutions. Later, the undissolved residue was washed and dried, then, it was picked out using LEICA Wild M3B microscope. The selected specimens were photographed through the Scanning Electron Microscope (model Hitachi S4800) at the University of Valencia. The richness of the samples varied, between a minimum of five conodont pectiniform elements (sample CP/105d, with 0.61 kg) and a maximum of 396 (sample CP/89b, with 2 kg). All the samples provide 5656 total conodont pectiniform elements, determined at (sub)species (most) or genus rank. The preservation level was also variable. All of the conodont specimens are actually deposited in the Botany and Geology Department of the University of Valencia.\u003c/p\u003e \u003cp\u003eBiostratigraphical zonation has made in agreement with the Frasnian conodont standard zonation of Klapper, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e1989\u003c/span\u003e and Klapper and Kirchgasser, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; and the proposed Famennian conodont standard zonation from Spalletta et al., \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2017\u003c/span\u003e. Conventional conodont biofacies have been analyzed following standard models (Sandberg, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1976\u003c/span\u003e, Dreesen \u0026amp; Thorez, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e1980\u003c/span\u003e, Sandberg \u0026amp; Dreesen, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e1984\u003c/span\u003e and Corradini, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). The conodont biofacies was based on the counting of conodont specimens per genera and their relative percentages (Table\u0026nbsp;1). The genera specimens counting included Pa and I elements, juvenile specimens and those fragmentary specimens in which\u0026thinsp;\u0026ge;\u0026thinsp;60% of platform surface is preserved, allowing generic adscription. Seven genera were identified: \u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003ePolygnathus\u003c/em\u003e, \u003cem\u003eIcriodus\u003c/em\u003e, \u003cem\u003eAncyrodella\u003c/em\u003e, \u003cem\u003eAncyrognathus\u003c/em\u003e, \u003cem\u003eMehlina\u003c/em\u003e and \u003cem\u003ePelekysgnathus\u003c/em\u003e. \u003cem\u003eAncyrodella\u003c/em\u003e and \u003cem\u003eAncyrognathus\u003c/em\u003e were grouped as ancyrodellids in the specimens counting, due to ecological similitudes.\u003c/p\u003e"},{"header":"3 Biostratigraphical framework","content":"\u003cp\u003eThe biostratigraphical framework provides a detailed conodont zonation across the Frasnian\u0026ndash;Famennian boundary, through the middle Famennian (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e2\u003c/span\u003e). We improved the previous zonation from (Silv\u0026eacute;rio et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) subdividing the FZ13 Zone and the identification of one lower Famennian conodont zone.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e3.1 \u003cem\u003eUppermost Frasnian FZ13 Zone.\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eThe lower part of the studied section starts in the FZ13a subzone with the record of its index taxa \u003cem\u003ePalmatolepis bogartensis\u003c/em\u003e (sample CP/84); it extends up to sample CP/87b with the highest record of \u003cem\u003ePalmatolepis hassi\u003c/em\u003e, which according to Klapper and Kirchgasser (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) ranges near to the base of FZ13b subzone. Other conodont taxa recorded in association within this subzone are: \u003cem\u003ePalmatolepis winchelli\u003c/em\u003e, \u003cem\u003ePolygnathus webbi\u003c/em\u003e, \u003cem\u003ePolygnathus decorosus\u003c/em\u003e from the base of this unit, and \u003cem\u003ePolygnathus lodinensis\u003c/em\u003e, \u003cem\u003ePolygnathus normalis\u003c/em\u003e, \u003cem\u003ePalmatolepis boogaardi\u003c/em\u003e, \u003cem\u003eAncyrodella curvata\u003c/em\u003e late form and \u003cem\u003eAncyrognathus asymmetricus\u003c/em\u003e starting the upper half of the zone and \u003cem\u003ePolygnathus politus\u003c/em\u003e (unique record in sample CP/85). The lower boundary of the FZ13b subzone is marked by the entry of \u003cem\u003ePalmatolepis linguiformis\u003c/em\u003e (Girard et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), however, this taxon is not recorded in the Compte section. Thus, tentatively we place this subzone between the LAD of \u003cem\u003ePalmatolepis hassi\u003c/em\u003e (sample CP/87b) and the base of the FZ13c subzone (CP/92 base). Within this zone, all taxa from the previous zone except \u003cem\u003eP. politus\u003c/em\u003e and \u003cem\u003ePa\u003c/em\u003e. \u003cem\u003ehassi\u003c/em\u003e are recorded. Besides, \u003cem\u003eIcriodus alternatus alternatus\u003c/em\u003e appears (sample CP/91-base). \u003cem\u003ePolygnathus decorosus\u003c/em\u003e has is LAD at the top of the zone; other taxa continue in the following zone. The base of FZ13c subzone is defined by the LAD of \u003cem\u003ePalmatolepis linguiformis\u003c/em\u003e (Girard et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), which is not recorded in the Compte section. However, \u003cem\u003ePalmatolepis ultima\u003c/em\u003e appears close to the base (Klapper, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) and can be used in the section Compte to approximate the base of this subzone (sample CP/92-base). Yazdi (\u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e1999\u003c/span\u003e) also considers that \u003cem\u003eIcriodus alt. mawsonae\u003c/em\u003e appears in the base of this subzone; the FAD of this taxon in the section Compte is in sample CP/92-base as well. All the conodonts that cross the base of this zone from the previous one disappear within the zone, except \u003cem\u003eIc. alt. alternatus\u003c/em\u003e which crosses de F/F boundary and ends in the lower Famennian \u003cem\u003etermini\u003c/em\u003e Zone. Other three new taxa appear in this zone: \u003cem\u003ePalmatolepis ultima\u003c/em\u003e, \u003cem\u003ePa\u003c/em\u003e. \u003cem\u003ejuntianensis\u003c/em\u003e and \u003cem\u003eAncyrognathus amana\u003c/em\u003e (sample CP/92-base); the latter two end in the lower part of the zone. \u003cem\u003ePolygnathus lodinensis\u003c/em\u003e, \u003cem\u003ePalmatolepis boogaardi\u003c/em\u003e, \u003cem\u003eAncyrognathus asymmetricus\u003c/em\u003e, \u003cem\u003ePolygnathus webbi\u003c/em\u003e, \u003cem\u003ePalmatolepis juntianensis\u003c/em\u003e and \u003cem\u003eAncyrognathus amana\u003c/em\u003e became extinct around 2 m below, in sample CP/92a. The last record of typical uppermost Frasnian conodont taxa in the Compte section is in sample CP/92b with the LAD of \u003cem\u003ePalmatolepis bogartensis\u003c/em\u003e, \u003cem\u003ePalmatolepis winchelli\u003c/em\u003e and \u003cem\u003eAncyrodella curvata\u003c/em\u003e late form. \u003cem\u003ePalmatolepis bogartensis\u003c/em\u003e, \u003cem\u003ePalmatolepis winchelli\u003c/em\u003e, \u003cem\u003eAncyrodella curvata\u003c/em\u003e late form and \u003cem\u003eAncyrognathus assymmetricus\u003c/em\u003e became extinct approximately 50 cm below (CP/92b), whereas \u003cem\u003ePalmatolepis ultima\u003c/em\u003e, \u003cem\u003ePalmatolepis ultima\u003c/em\u003e, \u003cem\u003eIcriodus alt. alternatus\u003c/em\u003e and \u003cem\u003eIcriodus alt. mawsonae\u003c/em\u003e crossed the Frasnian\u0026ndash;Famennian boundary.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e3.2 \u003cem\u003ePalmatolepis delicatula platys and Palmatolepis minuta minuta zones\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eThe first Famennian sample (CP/92c) records three Frasnian taxa, \u003cem\u003ePalmatolepis ultima\u003c/em\u003e, \u003cem\u003eIcriodus alt. mawsonae\u003c/em\u003e and \u003cem\u003eIcriodus alt. alternatus\u003c/em\u003e and the entry of \u003cem\u003ePalmatolepis delicatula delicatula\u003c/em\u003e, \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e, \u003cem\u003ePalmatolepis triangularis\u003c/em\u003e and \u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e, suggesting the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone, which is defined by the index taxon; the top of the zone is limited by the LAD of \u003cem\u003ePalmatolepis ultima\u003c/em\u003e (Spalletta et al., \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Higher, the sample CP/92d records the FAD of \u003cem\u003eAncyrognathus sinelaminus\u003c/em\u003e and \u003cem\u003ePalmatolepis lobicornis\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eDue to the high condensation in this part of the section (Silv\u0026eacute;rio et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), the two first Famennian zones (\u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e Zone and \u003cem\u003ePalmatolepis triangularis\u003c/em\u003e Zone) are not recorded in the Compte section. The \u003cem\u003ePalmatolepis minuta minuta\u003c/em\u003e Zone is identified by the entry of the index taxa in sample CP/93 and is extremely condensed. \u003cem\u003ePalmatolepis del. delicatula\u003c/em\u003e ranges up to this zone.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.3 \u003cem\u003ePalmatolepis crepida and Palmatolepis termini zones.\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eThe base of the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone is marked by the entry of the index taxon \u003cem\u003ePalmatolepis crepida\u003c/em\u003e in sample CP/94a. Concomitant with it, \u003cem\u003ePalmatolepis tenuipunctata\u003c/em\u003e, \u003cem\u003ePalmatolepis quadrantinodosalobata\u003c/em\u003e and \u003cem\u003ePalmatolepis regularis\u003c/em\u003e appear in the base of this zone. \u003cem\u003ePalmatolepis sandbergi\u003c/em\u003e is recorded only in this zone, from slightly above the base to the upper half of this zone (samples CP/94b to CP/95). \u003cem\u003ePalmatolepis werneri\u003c/em\u003e is also recorded in this zone (samples CP/94c to CP/95). \u003cem\u003eAncyrognathus sinelaminus\u003c/em\u003e ups to the lower half of the zone (CP/94b). \u003cem\u003ePolygnathus communis communis\u003c/em\u003e, \u003cem\u003ePelekysgnathus planus\u003c/em\u003e and \u003cem\u003ePalmatolepis mint. loba\u003c/em\u003e have the first record of the section in this zone. \u003cem\u003ePalmatolepis triangularis\u003c/em\u003e ranges up to the upper half of this zone (sample CP/95). The \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone starts in the base of Bed 96 (sample CP/96) with the first record of the index taxa. \u003cem\u003ePalmatolepis mint. wolskae\u003c/em\u003e and \u003cem\u003ePolygnathus gb. eoglaber\u003c/em\u003e appear in the base of this zone.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.4 \u003cem\u003ePalmatolepis glabra prima and Palmatolepis glabra pectinata zones.\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eBarrera-Lahoz et al., (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), recognized the \u003cem\u003ePalmatolepis glabra prima\u003c/em\u003e and \u003cem\u003ePalmatolepis glabra pectinata\u003c/em\u003e zones by their respective index taxa. The base of \u003cem\u003ePalmatolepis glabra prima\u003c/em\u003e Zone is located in the upper part of the Comabella Fm. at the top of Bed 98 (sample CP/98c). The base of \u003cem\u003ePalmatolepis glabra pectinata\u003c/em\u003e is located in the uppermost part of the Comabella Fm. at the top of Bed 104 (sample CP/104c).\u003c/p\u003e \u003cp\u003eSeveral taxa cross the base of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone and have their LAD within the zone: \u003cem\u003eIc. alt. mawsonae\u003c/em\u003e, \u003cem\u003ePalmatolepis tenuipunctata\u003c/em\u003e, \u003cem\u003ePalmatolepis quadrantinodosalobata\u003c/em\u003e, \u003cem\u003ePalmatolepis crepida\u003c/em\u003e, \u003cem\u003ePalmatolepis lobicornis Pa. regularis, Pa. minuta loba\u003c/em\u003e, and \u003cem\u003ePa. termini\u003c/em\u003e. Besides, there are two taxa that appear above the base and continue higher in the sequence: \u003cem\u003ePolygnathus gl. glaber\u003c/em\u003e (CP/99c) and \u003cem\u003ePolygnathus semicostatus\u003c/em\u003e (CP/101b)\u003c/p\u003e \u003cp\u003eExcept \u003cem\u003ePa. minuta wolskae\u003c/em\u003e, none other taxa crossing the base from the previous zone became extinct in the \u003cem\u003ePalmatolepis glabra pectinata\u003c/em\u003e Zone. Three conodont taxa appear slightly above the base and continue higher: \u003cem\u003ePolygnathus nodocostatus nodocostatus\u003c/em\u003e and \u003cem\u003ePolygnathus nod. ovatus\u003c/em\u003e both in sample CP/105a and Palmatolepis \u003cem\u003eperlobata schindewolfi\u003c/em\u003e, in sample CP/105b\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.5 \u003cem\u003ePalmatolepis rhomboidea, Palmatolepis gracilis gracilis\u003c/em\u003e and \u003cem\u003ePalmatolepis marginifera marginifera\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eThe \u003cem\u003ePalmatolepis rhomboidea, Palmatolepis gracilis gracilis\u003c/em\u003e and \u003cem\u003ePalmatolepis marginifera marginifera\u003c/em\u003e zones are identified with the appearance of their respective index taxa (Barrera-Lahoz et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). The base of \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e is located in the lowermost part of the La Mena Fm. (sample CP/107) Within this zone, the conodont association is mainly based on \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e, \u003cem\u003ePalmatolepis glabra\u003c/em\u003e-stock, \u003cem\u003ePalmatolepis perlobata\u003c/em\u003e-stock and \u003cem\u003ePolygnathus nodocostatus\u003c/em\u003e-stock taxa. \u003cem\u003eIcriodus alt. alternatus\u003c/em\u003e ends its record in the upper part of the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone (sample CP/111a-1). Along this zone, different taxa appear: \u003cem\u003ePalmatolepis\u003c/em\u003e cf. \u003cem\u003eklapperi\u003c/em\u003e in the base, \u003cem\u003eIcriodus cornutus\u003c/em\u003e in the middle (CP/109b), \u003cem\u003ePolygnathus bouckaerti\u003c/em\u003e (CP/110) and \u003cem\u003ePolygnathus eoglaber\u003c/em\u003e (CP/111a-1) in the upper half of the zone (for further details see Barrera-Lahoz et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Near the top of the zone, \u003cem\u003ePalmatolepis gl. acuta\u003c/em\u003e (CP/111b) and \u003cem\u003ePalmatolepis gl. lepta\u003c/em\u003e (CP/111c) begin its record. The base of the \u003cem\u003ePalmatolepis gracilis gracilis\u003c/em\u003e Zone is located at the middle part of La Mena Fm. (base of Bed 112). Two taxa coming from lower zones, end its record in this zone: \u003cem\u003ePolygnathus semicostatus\u003c/em\u003e (Bed 112) and \u003cem\u003ePolygnathus padovanii\u003c/em\u003e (Bed 113). \u003cem\u003ePolygnathus subnormalis\u003c/em\u003e is recorded exclusively in this zone in the Compte section (Beds 112\u0026ndash;113). Numerous taxa appear in this zone: \u003cem\u003ePalmatolepis per. helmsi\u003c/em\u003e (CP/112a), \u003cem\u003ePolygnathus lauriformis\u003c/em\u003e (CP/112c), \u003cem\u003eMehlina strigosa\u003c/em\u003e (CP/112c), \u003cem\u003ePalmatolepis gl. glabra\u003c/em\u003e (CP/112d), \u003cem\u003ePolygnathus triphyllatus\u003c/em\u003e (CP/112e), \u003cem\u003ePalmatolepis quad. inflexa\u003c/em\u003e (CP/112g). \u003cem\u003ePalmatolepis stoppeli\u003c/em\u003e is recorded near the top of this zone (CP/113c). The base of the \u003cem\u003ePalmatolepis marginifera marginifera\u003c/em\u003e Zone is located in the upper part of La Mena Fm. (base of Bed 114) and it is marked by the appearance of the index taxa, which is accompanied by \u003cem\u003ePalmatolepis quad. quadrantinodosa\u003c/em\u003e and \u003cem\u003ePalmatolepis quad. inflexoidea\u003c/em\u003e (CP/114a). \u003cem\u003ePolygnathus glaber medius\u003c/em\u003e and \u003cem\u003ePalmatolepis per. sigmoidea\u003c/em\u003e start in sample CP/117, whereas \u003cem\u003ePolygnathus longiusculus\u003c/em\u003e appears in sample CP/118b. Numerous taxa end its record in this zone: \u003cem\u003ePolygnathus com. communis\u003c/em\u003e (CP/114a), \u003cem\u003ePolygnathus nod. ovatus\u003c/em\u003e (CP/114b), \u003cem\u003ePolygnathus nod. nodocostatus\u003c/em\u003e (CP/116), \u003cem\u003eMehlina strigosa\u003c/em\u003e (CP/114b), \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e and \u003cem\u003ePalmatolepis gl. acuta\u003c/em\u003e in CP/117, \u003cem\u003ePolygnathus triphyllatus\u003c/em\u003e CP/118a and \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e and \u003cem\u003ePalmatolepis per. helmsi\u003c/em\u003e in CP/119.\u003c/p\u003e \u003c/div\u003e"},{"header":"4 Conodont biofacies","content":"\u003cp\u003eSeddon (1970) started the study of the conodont biofacies defining the neritic\u0026ndash;reef Icriodid and Palmatolepid pelagic facies from the Upper Devonian in the Canning Basin. Later, Seddon and Sweet (1971) proposed a paleoecological model for the conodont facies and its distribution related to water depth. Seddon and Sweet (1971) and, subsequently, Sandberg (1976) demonstrated the relation between the proportion of conodont genera and water depth Thus, the conodont biofacies were established as water depth approximation proxy. Sandberg (1976) defined five new biofacies from the late Famennian \u003cem\u003estyriacus\u003c/em\u003e Zone (applicable to other Famennian zones): Palmatolepid\u0026ndash;Bispathoid, Palmatolepid\u0026ndash;Polygnathid, Polygnathid\u0026ndash;Icriodid, Polygnathid\u0026ndash;Pelekysgnathid and Clydagnathid. Dreesen and Thorez (1980) described the ecological distribution of \u003cem\u003ePolylophodonta\u003c/em\u003e and polygnathids of the \u003cem\u003eP.\u003c/em\u003e \u003cem\u003esemicostatus\u0026nbsp;\u003c/em\u003eand \u003cem\u003enodocostatus\u003c/em\u003e groups from the Famennian of Belgium. Sandberg and Dreesen (1984) reviewed the shallow water environments conodont zonation and included a new Anthognathid biofacies for hypersaline environments. Savoy and Harris (1993) reported the conodont biofacies separating species in morphological groups from the Devonian and lowermost Carboniferous of the Rocky Mountains. Matyja (1993) analyzed new Polygnathid\u0026ndash;Palmatolepid biofacies and mentioned conodont species distribution in biofacies from Western Pomerania region, Poland. Corradini (1998) documented new deep water Palmatolepid\u0026ndash;Icriodid biofacies, specifically cosmopolitan icriodid taxa in the Devonian of Sardinia, Italia. Later, L\u0026uuml;ddecke et al. (2017) described detailed biofacies based on conodont species groups in the middle Famennian of the Rhenish Massif (Germany); however, Girard et al. (2020) challenged this approach, as it is difficult to apply in relative long\u0026ndash;time record, due to the species evolution and replacement. We agree with this latter opinion.\u003c/p\u003e\n\u003cp\u003eThe combination of conodont records in the Compte section allows recognition of five biofacies (Fig. 3). \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003eis always present in the studied time-interval, representing the 65% of the total specimens. \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003eis the second most abundant genus representing the 27%, but in several levels is absent. Less proportion have \u003cem\u003eIcriodus\u003c/em\u003e, 5%, Ancyrodellids 1% (including together the genera \u003cem\u003eAncyrodella\u003c/em\u003e and \u003cem\u003eAncyrognathus\u003c/em\u003e), \u003cem\u003eMehlina\u003c/em\u003e and \u003cem\u003ePelekysgnathus\u003c/em\u003e both contains less than 1% of all specimens.\u003c/p\u003e\n\u003cp\u003e4.1\u003cem\u003e\u0026nbsp;Conodont biofacies description.\u003c/em\u003e\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003e\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eThe most abundant genus is \u003cem\u003ePalmatolepis\u003c/em\u003e counting for between the 75\u0026ndash;98% of the total specimens \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003erepresents 1\u0026ndash;23% or it is absent in some samples (Tab. 1). \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003erepresents 2\u0026ndash;17% or is lacking (Tab. 1). Ancyrodellids are scarce representing 2\u0026ndash;9%. \u003cem\u003eMehlina\u003c/em\u003e is residual, recorded only in one sample (CP/114b) where it represents 0.9%.\u003c/p\u003e\n\u003col start=\"2\"\u003e\n \u003cli\u003e\u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cem\u003ePalmatolepis\u003c/em\u003e represents the most abundant genus, but in lesser proportion than in the \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003ebiofacies. The percentage comprises between the 50\u0026ndash;75% of the total specimens. \u003cem\u003ePolygnathus\u003c/em\u003e is abundant reaching the 20\u0026ndash;46%. \u003cem\u003ePolygnathus semicostatus\u003c/em\u003e is the most abundant taxon in CP/110 and CP/111a-1 and the \u003cem\u003enodocostatus\u003c/em\u003e group and \u003cem\u003ePolygnathus lauriformis\u0026nbsp;\u003c/em\u003eare frequent in Beds 112\u0026ndash;114, specially in CP114/a (see tables in Barrera-Lahoz et al., 2025 for specimens count per taxon). \u003cem\u003eIcriodus\u003c/em\u003e and Ancyrodellids represent at least 2\u0026ndash;6% or are absent. \u003cem\u003eMehlina\u0026nbsp;\u003c/em\u003eis accessory in four samples, representing only 2\u0026ndash;5% of the total specimens.\u003c/p\u003e\n\u003col start=\"3\"\u003e\n \u003cli\u003e\u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003eis dominant with the 60\u0026ndash;80% of the total specimens. \u003cem\u003ePolygnathus lodinensis\u0026nbsp;\u003c/em\u003eand \u003cem\u003ePolygnathus decorosus\u003c/em\u003e are the frequent taxa through the Frasnian, whereas \u003cem\u003ePolygnathus semicostatus\u003c/em\u003e and \u003cem\u003ePolygnathus\u003c/em\u003e of the \u003cem\u003enodocostatus\u003c/em\u003e group are the common Famennian taxa. The second abundant genus is \u003cem\u003ePalmatolepis\u003c/em\u003e representing the 12\u0026ndash;40% of the total specimens. When present, \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003eand Ancyrodellids are less common, representing between 1\u0026ndash;6%.\u003c/p\u003e\n\u003col start=\"4\"\u003e\n \u003cli\u003e\u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cem\u003ePalmatolepis\u003c/em\u003e is the most frequent genus counting for the 80\u0026ndash;54% of the total specimens and \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003ethe second, representing between the 6%\u0026ndash;38% of the total specimens. Other accessory genera, always being less numerous than \u003cem\u003eIcriodus\u003c/em\u003e, are \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003ebetween 4\u0026ndash;10% and Ancyrodellids, up to 10%.\u003c/p\u003e\n\u003col start=\"5\"\u003e\n \u003cli\u003e\u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eThis new biofacies is characterized by \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003epeaks, representing the most frequent genus, reaching up to 49% of the total specimens; \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003earound 34% of total specimens is the second. The \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003erepresentative taxa are cosmopolitan species of the \u003cem\u003ealternatus\u0026nbsp;\u003c/em\u003egroup: \u003cem\u003eIcriodus alt. alternatus\u0026nbsp;\u003c/em\u003eand \u003cem\u003eIcriodus alt. mawsonae\u003c/em\u003e, and the Pyrenean \u003cem\u003eIcriodus tumulosus\u003c/em\u003e. Accessory \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003erepresents 18\u0026ndash;22% of the total specimens.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e4.2 \u003cem\u003eConodont biofacies evolution through the Compte section\u0026nbsp;\u003c/em\u003e(Figure 3)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePolygnathus\u003c/em\u003e dominates the conodont fauna between Beds 84\u0026ndash;87, which belongs to most of the FZ13a subzone (Fig. 3); it represents around 52% with the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies. The frequent polygnathid taxa are \u003cem\u003ePolygnathus webbi\u003c/em\u003e, \u003cem\u003ePolygnathus decorosus\u003c/em\u003e, \u003cem\u003ePolygnathus lodinensis\u003c/em\u003e, \u003cem\u003ePolygnathus politus\u003c/em\u003e. The common palmatolepids are \u003cem\u003ePalmatolepis hassi\u003c/em\u003e, \u003cem\u003ePalmatolepis winchelli\u003c/em\u003e and \u003cem\u003ePalmatolepis bogartensis\u003c/em\u003e. The presence of \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003eand Ancyrodellids is low (\u0026lt;3%), in most of the FZ13a\u0026ndash;b subzones. The \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003econtent descends to 36% in Bed 87, through FZ13a\u0026ndash;b subzones boundary and the \u003cem\u003ePalmatolepis\u003c/em\u003e richness increases to 57%, turning into the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies. Then, the \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003econtent sharply increases up to 71%, returning the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in the base of Bed 89, in the lower part of FZ13b subzone, being \u003cem\u003ePolygnathus decorosus\u003c/em\u003e and \u003cem\u003ePolygnathus lodinensis\u0026nbsp;\u003c/em\u003ethe dominant taxa. Slightly higher, the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies returns (Beds 89\u0026ndash;90; Fig. 3); subsequently, the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies dominates most of the upper half of this subzone (Bed 91). Then, a sudden peak of \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003e(81%) at the top of Bed 91(uppermost FZ13b), represents the change to the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies. Higher, in the FZ13c subzone, the \u003cem\u003ePolygnathus\u003c/em\u003e proportion increases (9\u0026ndash;30%) returning the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies. Alongside FZ13c subzone, the abundance of \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003eand Ancyrodellids gradually increases reaching up to 20% and 10% respectively, at the top of this subzone. This \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003epeak resulted in the incoming of the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies at the end of the Frasnian in the Compte section. Within the lowest recorded Famennian Biozone (\u003cem\u003ePalmatolepis del. platys\u003c/em\u003e), two biofacies are observed, the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003e(sample CP/92c)\u003cem\u003e\u0026nbsp;\u003c/em\u003efollowed by the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies (sample CP/92d). Immediately above, in the \u0026ldquo;condensed\u0026rdquo; \u003cem\u003ePalmatolepis mint. minuta\u0026nbsp;\u003c/em\u003eZone, a second \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003epeak is recorded (49% of specimens abundance) resulting in the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in sample CP/93. This peak is due to \u003cem\u003eIcriodus alt. alternatus\u003c/em\u003e. \u003cem\u003ePalmatolepis\u003c/em\u003e counts for the 47% of the total specimens, and it is represented by the \u003cem\u003edelicatula\u003c/em\u003e group, \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e, \u003cem\u003ePalmatolepis triangularis\u003c/em\u003e and \u003cem\u003ePalmatolepis lobicornis\u003c/em\u003e. \u003cem\u003ePolygnathus\u003c/em\u003e is accessory, almost 3%. After this \u003cem\u003eIcriodus\u003c/em\u003e peak, the icriodid content decreases in the base of \u003cem\u003ePalmatolepis crepida\u0026nbsp;\u003c/em\u003eZone with \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies and \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003erecovers its dominance through this zone and during the \u003cem\u003ePalmatolepis termini\u0026nbsp;\u003c/em\u003eand the lowermost part of the \u003cem\u003ePalmatolepis glabra prima\u003c/em\u003e zones, with an average of 80%, reaching a maximum of 98% at the base of \u003cem\u003ePalmatolepis termini\u0026nbsp;\u003c/em\u003eZone. \u003cem\u003ePolygnathus\u003c/em\u003e decreases gradually its abundance from 17 to 1% through the \u003cem\u003ecrepida\u003c/em\u003e Zone and then, keeps a moderated low abundance between 14 to 1%. \u003cem\u003eIcriodus\u003c/em\u003e recovers its abundance in the upper part of \u003cem\u003etermini\u0026nbsp;\u003c/em\u003eZone, reaching up to 19%. Accessory genera in this biofacies are Ancyrodellids with 2% in the lower part of the \u003cem\u003ePalmatolepis crepida\u0026nbsp;\u003c/em\u003eZone and \u003cem\u003ePelekysgnathus\u003c/em\u003e with 1% at the top of this zone. Higher, three \u003cem\u003eIcriodus\u003c/em\u003e peaks are recorded within the \u003cem\u003ePalmatolepis gl. prima\u0026nbsp;\u003c/em\u003eZone, resulting in an alternation of \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003eand \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003ebiofacies during this zone. The first peak occurs at the lower part of the zone, and the other two in the middle parts. As in the previous Famennian zones, the \u003cem\u003eIcriodus alternatus\u003c/em\u003e group is the dominant icriodid. \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003emaintains a low percentage reaching a maximum of 11% (Bed 100) and being absent in several samples, \u003cem\u003ee.g.\u0026nbsp;\u003c/em\u003eCP/104a (Tab. 1). Through the middle part of the \u003cem\u003ePalmatolepis\u003c/em\u003e \u003cem\u003egl. prima\u003c/em\u003e Zone, the abundance of pectiniform conodonts is relatively low; bed 100 yielded 8 specimens, and through the upper part of the zone its richness increased moderately (22\u0026ndash;59 specimens). In the highest sample of the zone (CP/104b), a sharply palmatolepid bloom is recorded, reaching 147 specimens (Tab. 1), 98% of which belong to \u003cem\u003ePalmatolepis\u003c/em\u003e. \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e, \u003cem\u003ePalmatolepis crepida\u003c/em\u003e, \u003cem\u003ePalmatolepis tenuipunctata\u003c/em\u003e and \u003cem\u003ePalmatolepis quadrantinodosalobata\u003c/em\u003e are the frequent taxa; the latter three have their highest record in this zone. A new \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003epeak (48%) is recorded in the base of the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e Zone\u003cem\u003e\u0026nbsp;\u003c/em\u003e(sample CP/104c), returning the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies. \u003cem\u003eIcriodus tumulosus\u003c/em\u003e, endemic taxon in the Pyrenees, is the only icriodid in this biofacies. \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003erepresents the 34% and \u003cem\u003ePolygnathus\u003c/em\u003e reaches the\u003cem\u003e\u0026nbsp;\u003c/em\u003e18%. Higher in the zone, the abundance of \u003cem\u003ePolygnathus\u003c/em\u003e increases (60% to 80% of the specimens) peaking in Bed 105 (Tab. 1); thus, the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is recorded through this zone. The common polygnathids are \u003cem\u003ePolygnathus semicostatus\u003c/em\u003e and \u003cem\u003ePol\u003c/em\u003e. of the \u003cem\u003enodocostatus\u003c/em\u003e group, whereas \u003cem\u003ePolygnathus padovanii\u0026nbsp;\u003c/em\u003eand \u003cem\u003ePolygnathus com. communis\u0026nbsp;\u003c/em\u003eare accessory. The record of \u003cem\u003eIcriodus\u003c/em\u003e in this zone is limited to two samples, (CP/104c -the peak one- and CP/105a) . The \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003ebiofacies sharply appears in the base of the subsequent \u003cem\u003ePalmatolepis rhomboidea\u0026nbsp;\u003c/em\u003eZone, with 90% of abundance in the base of Bed 107; the other 10% corresponds to \u003cem\u003ePolygnathus\u003c/em\u003e. The increase in the number of polygnathids leads to the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003ebiofacies up to middle parts of the zone (sample CP/109a). Then, a new (and last one) icriodid peak (sample CP/109b) marks the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies, with \u003cem\u003eIcriodus\u0026nbsp;\u003c/em\u003ereaching at least 44% and \u003cem\u003ePalmatolepis\u003c/em\u003e 33%. From this sample to the sample CP/111b the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003ebiofacies continues. The increase in the number of \u003cem\u003ePalmatolepis\u003c/em\u003e across the boundary between the \u003cem\u003ePa. rhomboidea\u003c/em\u003e and the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones results in the returning of the \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003ebiofacies in the base of Bed 112. Higher, \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003ereaches up to the 76\u0026ndash;80% of the total specimens. Representative taxa are \u003cem\u003ePalmatolepis glabra\u003c/em\u003e stock \u003cem\u003ePolygnathus padovanii\u003c/em\u003e, \u003cem\u003ePolygnathus triphyllatus\u003c/em\u003e and \u003cem\u003ePolygnathus lauriformis\u003c/em\u003e. \u003cem\u003eMehlina\u0026nbsp;\u003c/em\u003eappears as accessory with 2%. The progressive augment of \u003cem\u003ePolygnathus\u003c/em\u003e, with a maximum in sample CP/113a (54%) results in the re-occurrence of the \u003cem\u003ePolygnathus-Palmatolepis\u003c/em\u003e biofacies. The \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies returns from the upper part of Bed 113 through the base of Bed\u003cem\u003e\u0026nbsp;\u003c/em\u003e114, where corresponds to the lowest interval of \u003cem\u003ePa. mag.\u0026nbsp;\u003c/em\u003e\u003cem\u003emarginifera\u003c/em\u003e Zone. \u003cem\u003ePalmatolepis\u003c/em\u003e is the dominant genus from the lower part of the \u003cem\u003ePalmatolepis mg. marginifera\u0026nbsp;\u003c/em\u003eZone to the end of the section (Beds 114\u0026ndash;120), with values \u003cem\u003ebetween\u003c/em\u003e 75\u0026ndash;89%, resulting in the return of the \u003cem\u003ePalmatolepis\u0026nbsp;\u003c/em\u003ebiofacies, Representative palmatolepid taxa in this zone are those of the \u003cem\u003ePalmatolepis\u003c/em\u003e \u003cem\u003eglabra\u003c/em\u003e, \u003cem\u003ePalmatolepis\u003c/em\u003e \u003cem\u003eperlobata\u003c/em\u003e and \u003cem\u003ePalmatolepis\u003c/em\u003e \u003cem\u003equadrantinodosa\u003c/em\u003e groups and \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e. The \u003cem\u003ePolygnathus\u0026nbsp;\u003c/em\u003epercentage ranges between 11\u0026ndash;20% of the total specimens.\u0026nbsp;\u003c/p\u003e"},{"header":"5 Discussion","content":"\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e\u003cem\u003e5.1 Paleoecological interpretations\u003c/em\u003e.\u003c/h2\u003e \u003cp\u003eUpper Devonian conodont biofacies provide information on relative water depth of depositional environments and eustatic changes, especially in monotonous stratigraphical sequences (L\u0026uuml;eddecke et al., 2017). \u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003eMehlina\u003c/em\u003e, \u003cem\u003eBranmehla\u003c/em\u003e and \u003cem\u003eBispathodus\u003c/em\u003e are often related with deep waters or offshore environments (Sandberg, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1976\u003c/span\u003e). \u003cem\u003ePolygnathus\u003c/em\u003e is related with intermediate waters, shallower than \u003cem\u003ePalmatolepis\u003c/em\u003e (Sandberg, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1976\u003c/span\u003e). \u003cem\u003eIcriodus\u003c/em\u003e is related to shallow waters (Sandberg, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1976\u003c/span\u003e; Sandberg and Dreesen, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e1984\u003c/span\u003e), however, several cosmopolitan taxa, as those of the \u003cem\u003ealternatus\u003c/em\u003e group, \u003cem\u003eIcriodus olivierii\u003c/em\u003e and \u003cem\u003eIcriodus cornutus\u003c/em\u003e are found in pelagic environments (Corradini, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs previously mentioned, the conodont succession in the Compte section shows different faunal changes and alternance of biofacies. The first of these changes occurs in the upper part of the FZ13a where the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e is replaced by the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies suggesting a transgressional trend. A \u003cem\u003ePolygnathus\u003c/em\u003e peak in the lower part of FZ13b subzone leads to the return of the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e) and is interpreted as a regressive trend with the \u003cem\u003ePolygnathus\u003c/em\u003e peak in the base of Bed 89 (\u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies). Palmatolepid\u0026ndash;Polygnathid biofacies returns through the middle of FZ13b subzone. Another \u003cem\u003ePolygnathus\u003c/em\u003e peak is recorded in the upper half of this subzone (Bed 91) suggests another regressive trend. Near to the top of FZ13b subzone (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e), a sharply dominance of \u003cem\u003ePalmatolepis\u003c/em\u003e (\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies) is recorded. Thus, the abrupt increase of \u003cem\u003ePalmatolepis\u003c/em\u003e suggests a markedly transgressive trend. During the FZ13c subzone \u003cem\u003eIcriodus\u003c/em\u003e increases gradually, reaching a maximum of 20% in sample CP/92b (\u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies). The \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies dominates through the FZ13c subzone; however, near the top, the occurrence of the Palmatolepid\u0026ndash;Icriodid biofacies suggests a regressive trend close to the Frasnian\u0026ndash;Famennian boundary. During the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e and \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e zones the icriodid content remains high, reaching 49% in sample CP/93; consequently, the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies develops in the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone. This high icriodid content may suggest a regressive trend, nevertheless, opportunistic taxa as those of the \u003cem\u003ealternatus\u003c/em\u003e group might also be present in pelagic facies occupying empty ecological niches after the extinction event (Corradini, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). The significant content of \u003cem\u003eIcriodus\u003c/em\u003e suggests shallower conditions than those of the Palmatolepid\u0026ndash;Icriodid biofacies, probably as result of transport of shallower sediments related with eustatic sea\u0026ndash;level fall in the carbonated ramp. The \u003cem\u003eIcriodus\u003c/em\u003e content decreases through the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e and \u003cem\u003ePalmatolepis termini\u003c/em\u003e zones where the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is almost exclusive, suggesting a transgressive trend. The small in the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone content of \u003cem\u003ePelekysgnathus\u003c/em\u003e is interpreted as result of transport from the nearshore area. During the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e, three icriodid peaks (\u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies) are recorded in Beds 99, 101 and 102, which could suggest short regressive fluctuations. In the upper part of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone (sample CP/104b) a bloom of palmatolepids is recorded, reaching 98% of the total species suggesting a sharply transgressive trend. The beginning of the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e Zone records an abrupt change of biofacies: Icriodid\u0026ndash;Palmatolepid (indicate samples) followed by the Polygnathid\u0026ndash;Palmatolepid biofacies (samples); these biofacies change may be the expression of a new regressive trend. The polygnathid taxa in the Polygnathid\u0026ndash;Palmatolepid biofacies (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e2\u003c/span\u003e) are found in shallower environments (Dreesen and Thorez, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e1980\u003c/span\u003e), thus, a regressive trend through the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e is plausible. The abrupt return of the palmatolepid dominance at the base of \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone suggests deeper pelagic conditions, which are interrupted by the next icriodid peak leading to the Icriodid\u0026ndash;Palmatolepid biofacies in the middle of the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone (Bed 109), suggesting a sharply sea\u0026ndash;level fall. The restore to abundance of Palmatolepids and of the Palmatolepid\u0026ndash;Polygnathid biofacies suggests deeper conditions through the upper part of the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone. This deepening trend continues in the transition between the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e and \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones. The following Palmatolepid\u0026ndash;Polygnathid biofacies, and specially, the subsequent \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone (Bed 113) suggest another regressive pulse. During the upper part of the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone and the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e Zone, the dominance of \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies suggests deeper water environments, and, thus, a new transgressive pulse.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e5.2 \u003cem\u003eConodont biofacies evolution and diversity comparison with other regions\u003c/em\u003e.\u003c/h2\u003e \u003cp\u003eThrough the Frasnian\u0026ndash;Famennian boundary biotic changes in the conodont faunas are recorded worldwide. These changes seem to be connected with eustatic fluctuations at the end of the Frasnian extinction (Sandberg et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1988\u003c/span\u003e). \u003cem\u003eAncyrodella\u003c/em\u003e and \u003cem\u003eOzarkodina\u003c/em\u003e became extinct at the end Frasnian, and \u003cem\u003ePalmatolepis\u003c/em\u003e was reduced to a unique taxon: \u003cem\u003ePalmatolepis ultima\u003c/em\u003e. All species of Frasnian \u003cem\u003ePolygnathus\u003c/em\u003e disappear and \u003cem\u003eIcriodus\u003c/em\u003e did not suffer a major extinction event; a characteristic peak of \u003cem\u003eIcriodus\u003c/em\u003e is recorded in different Euramerican zones in the basal Famennian interval (Sandberg et al, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1988\u003c/span\u003e, Sch\u0026uuml;lke and Popp, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e, Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Through the lower and middle Famennian different conodont biofacies shifts are recorded in several regions; thus, a comparison with those changes recorded in the Compte section is possible.\u003c/p\u003e \u003cp\u003eIn the Central Pyrenees, Els Castells section, (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e1\u003c/span\u003ec; Fig.\u0026nbsp;4.1), different conodont biofacies are recorded through Frasnian\u0026ndash;Famennian transition (S\u0026aacute;nchez de Posada et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Within FZ13, \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e is the frequent biofacies, like in the Compte section where polygnathids are frequent in the lower part of the zone. The last Frasnian sample in Els Castells shows a maximum abundance of \u003cem\u003ePalmatolepis\u003c/em\u003e, contrasting with the Palmatolepid\u0026ndash;Icriodid biofacies in the Compte section. The first four Famennian samples belonging to the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e zones show a dominance of \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies, with a peak of \u003cem\u003eIcriodus\u003c/em\u003e in the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone in Els Castells, unlike the sharply \u003cem\u003eIcriodus\u003c/em\u003e peak in Compte section during the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone.\u003c/p\u003e \u003cp\u003eSimilar biofacies with the studied section are found in the Palentine Domain in the Cantabrian Zone (Fig.\u0026nbsp;4.2): \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e within the upper Frasnian and \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e in the lower Famennian (Sanz-L\u0026oacute;pez et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e1999\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWithin the lower Famennian (\u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e to \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones) the frequent biofacies in Col des Tribes section, Montagne Noir (Fig.\u0026nbsp;4.3) is the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e (Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). During the \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone, a minor icriodid peak (\u0026lt;\u0026thinsp;25%) is recorded like in the Compte section. The abrupt palmatolepid abundance, in \u003cem\u003ePalmatolepis termini\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e transition in Compte section, is recorded at the top of \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone in Col des Tribes. There, in the base of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone another \u003cem\u003eIcriodus\u003c/em\u003e peak, reaching 25% is recorded, similar with the studied area; however, the icriodid content decreases through this zone in Col des Tribes section, whereas other two icriodid peaks are recorded in the Compte section. During the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e Zone the icriodid content is present but in the base of the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone a Palmatolepid abundance similar to the Compte section is recorded. A minor \u003cem\u003eIcriodus\u003c/em\u003e peak is recorded in the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone, whereas this peak is not recorded in the Compte section. In the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e Zone the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is dominant, similar to the Compte section. In the Coumiac section, slight differences related to fluctuations of icriodid abundance percentage (Sch\u0026uuml;lke, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e1999\u003c/span\u003e), in the Palmatolepid\u0026ndash;Icriodid biofacies through \u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e\u0026ndash;\u003cem\u003ecrepida\u003c/em\u003e zones are observed. The end of the Frasnian is characterized there by a polygnathid abundance up to 55%, higher than in the Compte section. During the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone an icriodid peak (reaching 30%) was recorded showing difference with the palmatolepid dominance in the Compte section during this time. A second icriodid peak was identified during the \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone (reaching near to 50%) and shows a slightly similarity with minor peak in the Compte section. The entry of \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e is similar in these two sections with a minor \u003cem\u003eIcriodus\u003c/em\u003e peak.\u003c/p\u003e \u003cp\u003ePalmatolepids and polygnathids are the most abundant genera in Sardinia (Fig.\u0026nbsp;4.4) through lower and middle Famennian (Corradini, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Contrasting, the records in the Compte section show an abundance of palmatolepids and \u003cem\u003ePalamatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies dominate during the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis termini\u003c/em\u003e zones. During the \u003cem\u003ePalmatolepis termini\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e transition a high abundance of palmatolepids is recorded, similar with the studied section. Within \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone, palmatolepids are more abundant and in the \u003cem\u003ePalmatolepis gl. Pectinata\u003c/em\u003e Zone, the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies returns. The \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies dominate through \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e to \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e zones. Two recorded \u003cem\u003eIcriodus\u003c/em\u003e peaks in Sardinia are similar with those in the Compte section: the first in the lower part of the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e Zone and the second in the middle part of the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone.\u003c/p\u003e \u003cp\u003eDuring the FZ13 polygnathids are relative frequent in the Carnic Alps (Fig.\u0026nbsp;4.5) (Farabegoli et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), however, from the upper part of the FZ13b subzone, their abundance decreases. \u003cem\u003ePalmatolepis\u003c/em\u003e, similar with the Compte section, reaches high abundance in the uppermost part of the FZ13b subzone and keeps abundant through the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone. \u003cem\u003ePalmatolepis\u003c/em\u003e reaches 70\u0026ndash;80% of abundance during the Frasnian\u0026ndash;Famennian transition in the Carnic Alps. Palmatolepid biofacies is frequent in the lower Famennian and Polygnathid biofacies is present in the FZ13a subzone and \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone. In the Carnic Alps, \u003cem\u003eIcriodus\u003c/em\u003e is scarce in the middle of the FZ13b subzone, in the middle of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e and in the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e zones, similar with Compte section. The \u003cem\u003eIcriodus\u003c/em\u003e peaks are recorded in the FZ13c subzone and the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone share similarities with the Compte section, however, the peaks in the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone and in the top of the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e do not correspond with those peaks in the Compte section.\u003c/p\u003e \u003cp\u003ePalmatolepid\u0026ndash;Polygnathid biofacies is present during the FZ13 in the Moroccan Central Massif, Atlas Range (Fig.\u0026nbsp;4.6) (Lazreq, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). This biofacies continues within the lower Famennian up to the \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone and \u003cem\u003ePalmatolepis\u003c/em\u003e represents between 65\u0026ndash;75%. From the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e\u0026ndash;\u003cem\u003egl. pectinata\u003c/em\u003e upwards, the content of palmatolepids is higher, turning into the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies. This succession is different from the Compte section during this interval. The \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies returns within the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e\u0026ndash;\u003cem\u003egr. gracilis\u003c/em\u003e zones. Similar biofacies as in the Compte section are found in M\u0026rsquo;rirt area (Lazreq, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e1992\u003c/span\u003e), which starts in the end of the Frasnian with \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies. The icriodid abundance increases gradually up to the F/F boundary with relative abundance of ancyrodellids. However, the Moroccan \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is recorded from the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone until the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e. The \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies is present again from the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e to the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e zones.\u003c/p\u003e \u003cp\u003eIn the end of the Frasnian sequence, \u003cem\u003ePalmatolepis\u003c/em\u003e is the most abundant genus with up to 70%, followed by \u003cem\u003ePolygnathus\u003c/em\u003e with up to 15%, showing the palmatolepid biofacies in the Thuringian zone (Fig.\u0026nbsp;4.7) (Girard et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In the lower Famennian \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone, the percentage of \u003cem\u003eIcriodus\u003c/em\u003e increases, opposite to the Compte section. In Thuringia, palmatolepids are more abundant, reaching the 90%, from the \u003cem\u003ePalmatolepis termini\u003c/em\u003e. Also, a \u003cem\u003ePolygnathus\u003c/em\u003e peak (25%) is recorded in the \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone in contrast with the records in the Compte section.\u003c/p\u003e \u003cp\u003ePalmatolepid and Polygnathid biofacies dominate the end of the Frasnian sequence in Western Pomerania region (Fig.\u0026nbsp;4.8) (Matyja, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). The \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is frequent in the FZ12\u0026ndash;FZ13, reaching up to 50% of \u003cem\u003ePolygnathus webbi\u003c/em\u003e. During the FZ13b\u0026ndash;c subzones the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies dominates showing some similarities with the Compte section, including the ruling abundance of \u003cem\u003ePalmatolepis winchelli\u003c/em\u003e (58% of total specimens). During the \u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e zones the change of biofacies is too different with the Compte section. In both areas the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies develops, but the frequent taxa in Western Pomerania are \u003cem\u003eIcriodus\u003c/em\u003e of the \u003cem\u003ealternatus\u003c/em\u003e-stock, \u003cem\u003ePolygnathus praecursor\u003c/em\u003e and \u003cem\u003ePolygnathus procerus\u003c/em\u003e. Similar \u003cem\u003eIcriodus\u003c/em\u003e peak (51%) is recorded in the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone in both regions, however the secondary genus is \u003cem\u003ePolygnathus\u003c/em\u003e in contrast to the Compte section where the secondary is \u003cem\u003ePalmatolepis\u003c/em\u003e. From the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone through the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone, the sedimentary deposits are much deeper, similar to those of the Compte section. There is a sedimentation change at the entry of the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e Zone, with shallower biofacies: \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies.\u003c/p\u003e \u003cp\u003eThe Palmatolepid\u0026ndash;Polygnathid biofacies is recorded in the Holly Cross Mountains (Fig.\u0026nbsp;4.9) (Matyja and Narkiewicz, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e1992\u003c/span\u003e) during the upper part of the FZ13, with a low number of icriodids. At the uppermost Frasnian, the relative abundance of \u003cem\u003ePolygnathus\u003c/em\u003e decreases, similar with the decline observed in the Compte section. The faunistic composition changes in the lowermost Famennian (\u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e\u0026ndash;\u003cem\u003etriangularis\u003c/em\u003e zones) with a dominance of \u003cem\u003eIcriodus\u003c/em\u003e, reaching up to 53%, which is assigned to the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e mixed biofacies slightly similar with Compte section.\u003c/p\u003e \u003cp\u003eThe predominant biofacies from all sections of the South Urals region (Fig.\u0026nbsp;4.10) (Tagarieva, \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) is the palmatolepid biofacies in Bol\u0026rsquo;shaya Barma section. During the FZ13a\u0026ndash;b subzones in all Russian sections, the biofacies shows a major content of palmatolepids than the Compte section. Near to the F/F boundary in the FZ13c subzone, the icriodid biofacies is present in Akkyr, Ryauzyak and Kuk-Karauk sections, whereas the Palmatolepid\u0026ndash;Polygnathid biofacies dominates in the Bol\u0026rsquo;shaya Barma section, as in the Compte section. Through the F/F transition in the Akkyr section, the conodont diversity decreases and \u003cem\u003eIcriodus\u003c/em\u003e rises its relative abundance, thus, the \u003cem\u003eIcriodus\u003c/em\u003e biofacies is recorded to the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone, whereas in the Compte section, the Palmatolepid\u0026ndash;Polygnathid biofacies develops. In the Bol\u0026rsquo;shaya Barma section, \u003cem\u003eIcriodus\u003c/em\u003e is absent, keeping the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies through the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone, contrasting with the icriodid peak in the Compte section. The abundance of \u003cem\u003ePalmatolepis\u003c/em\u003e grows from the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e to the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e zones, showing \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in all Russian sections; however, the Compte section shows more biofacies variation during this time.\u003c/p\u003e \u003cp\u003eThe lowermost Famennian in the Central Iran region (Fig.\u0026nbsp;4.11) (Bahrami et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) is characterized by an \u003cem\u003eIcriodus\u003c/em\u003e peak (almost 50%) in the \u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e Zone and by a \u003cem\u003ePalmatolepis\u003c/em\u003e abundance (reaching 80%) through the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone with a strong icriodid peak in the middle part of the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone coincident with the Compte section, whereas different \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies is present during the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e\u0026ndash;\u003cem\u003egl. pectinata\u003c/em\u003e zones. Slightly similar shallow facies in the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e and \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones, with polygnathid biofacies dominance are observed in both regions. A \u003cem\u003ePelekysgnathus\u003c/em\u003e peak, reaching almost 50% of the genera abundance is recorded in the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone. From the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e Zone, \u003cem\u003ePalmatolepis\u003c/em\u003e are sharply abundant, about 70\u0026ndash;80%, which is slightly similar with the records in the Compte section.\u003c/p\u003e \u003cp\u003eIn Baruunhuurai Terrane, western Mongolia (Suttner et al., \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) different biofacies are recorded during the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e to the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e zones, being the most characteristic the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies (Fig.\u0026nbsp;4.12). The most significant difference with the Compte section is the relative abundance of \u003cem\u003eAncyrognathus\u003c/em\u003e in Mongolia, even though palmatolepids and polygnathids are the most numerous genera. At the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone, \u003cem\u003ePalmatolepis\u003c/em\u003e increases its abundance. Icriodids are less abundant than in the Compte section, with two minor peaks in \u003cem\u003ePalmatolepis crepida\u003c/em\u003e and \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e zones.\u003c/p\u003e \u003cp\u003ePalmatolepids are the most abundant taxa within the FZ13 in the Lali section in Guangxi region (Fig.\u0026nbsp;4.13) (Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), this abundance reaches almost 90%, however, in some samples polygnathids are important components of the biofacies, 60% of \u003cem\u003ePalmatolepis\u003c/em\u003e and 36% of \u003cem\u003ePolygnathus\u003c/em\u003e. A peak of \u003cem\u003eIcriodus\u003c/em\u003e, reaching 45%, characterizes the lowermost Famennian (\u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e Zone), whereas \u003cem\u003ePalmatolepis\u003c/em\u003e reaches 37%. These relative abundances are similar to the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in the Compte section. Then, the \u003cem\u003ePalmatolepis\u003c/em\u003e/\u003cem\u003eIcriodus\u003c/em\u003e ratio reverses (61% and 31%), indicating the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies. This biofacies is recorded in the base of the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone and continues through the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e\u0026ndash;\u003cem\u003ecrepida\u003c/em\u003e zones Higher, in the upper half of \u003cem\u003ePalmatolepis crepida\u003c/em\u003e to \u003cem\u003etermini\u003c/em\u003e zones, the \u003cem\u003ePalmatolepis\u003c/em\u003e abundance is greater, reaching the 95%. Within the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone, \u003cem\u003eIcriodus\u003c/em\u003e reaches between 15\u0026ndash;24%. In the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone, the content of \u003cem\u003eIcriodus\u003c/em\u003e is around 23\u0026ndash;28% except in the top of this zone, where a \u003cem\u003ePalmatolepis\u003c/em\u003e peak reaching almost 100%, is recorded. This is similar in the Compte section. The \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is the dominant through the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e to \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e zones.\u003c/p\u003e \u003cp\u003eIn the Yangdi section (Fig.\u0026nbsp;4.13) (Huang and Gong, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is the dominant during the FZ13a subzone, except for a high percentage of \u003cem\u003ePolygnathus\u003c/em\u003e at the top of this subzone. At the base of FZ13b subzone, as in the Compte section, a \u003cem\u003ePalmatolepis\u003c/em\u003e peak is recorded, followed by an increase in the \u003cem\u003ePolygnathus\u003c/em\u003e abundance resulting in the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies through the middle and upper part of this subzone and the following FZ13c subzone. At the top of the Frasnian, the increase in \u003cem\u003eIcriodus\u003c/em\u003e, which reaches 27%, develops the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies. In the lowermost Famennian, \u003cem\u003eIcriodus\u003c/em\u003e keeps the abundance, almost 53%, followed by palmatolepids and a low abundance of polygnathids, turning the Palmatolepid\u0026ndash;Polygnathid into the Palmatolepid\u0026ndash;Icriodid mixed biofacies. This biofacies ranges to the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone and then, the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is present through the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone.\u003c/p\u003e \u003cp\u003eThe Lali section shows some similarities with the distribution of biofacies in the Compte section. They are comparable in the high content of icriodids, showing Palmatolepid\u0026ndash;Polygnathid biofacies in \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e to \u003cem\u003ePalmatolepis crepida\u003c/em\u003e zones, and several peaks in \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone. The bloom of \u003cem\u003ePalmatolepis\u003c/em\u003e in the upper part of \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone is comparable to the Compte section. On the other hand, in the Yangdi section the Polygnathid\u0026ndash;Palmatolepid biofacies during the latest Frasnian (FZ13a\u0026ndash;c) is comparable with the Compte section, nevertheless, the lower Famennian biofacies content is too different between the Chinese and Pyrenean sections.\u003c/p\u003e \u003cp\u003eIn the Indiana region (USA), the Palmatolepid\u0026ndash;Polygnathid biofacies dominates through the upper Frasnian to lower Famennian (Fig.\u0026nbsp;4.14) (Sandberg et al., \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e1994\u003c/span\u003e). During the FZ13 the NorthAmerican Palmatolepid\u0026ndash;Polygnathid biofacies is different from the Compte section, where two polygnathid peaks are recorded. The icriodid content (0\u0026ndash;6%). is low in the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone, In the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e Zone, the high percentage of \u003cem\u003ePalmatolepis\u003c/em\u003e indicates the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies, which is comparable with Compte section.\u003c/p\u003e \u003cp\u003eDuring the upper Frasnian, palmatolepids and polygnathids have high relative abundance in the USA Great Central Basin (Fig.\u0026nbsp;4.15) (Morrow, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2000\u003c/span\u003e) with a peak of \u003cem\u003ePolygnathus\u003c/em\u003e in the FZ13b\u0026ndash;c subzones, similar to Compte section. The lower Famennian (\u003cem\u003ePalmatolepis subperlobata\u003c/em\u003e\u0026ndash;\u003cem\u003etriangularis\u003c/em\u003e zones) is characterized by a high percentage of \u003cem\u003eIcriodus\u003c/em\u003e, reaching 50%, especially within the \u003cem\u003ePalmatolepis triangularis\u003c/em\u003e Zone. From the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e Zone, there is an increase in the number of taxa of \u003cem\u003ePalmatolepis\u003c/em\u003e and \u003cem\u003ePolygnathus\u003c/em\u003e, however, the percentage of \u003cem\u003eIcriodus\u003c/em\u003e continues being relatively high through the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone.\u003c/p\u003e \u003cp\u003eThe Compte section shows similarities and discrepancies with different localities from Euramerica, Gondwana, Uralian Arc, Iran Block, Central Asian Orogenic Belt and South China Block in the relative proportions of conodont genera abundance and, consequently in the distribution and evolution of conodont biofacies from the upper Frasnian to the middle Famennian. During the FZ13, polygnathids are relative abundant until the top of FZ13b subzone, alternating the biofacies of \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e and \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies in East Euramerica (Europe) and South China regions (Matyja, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Zhang et al.; \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e, Farabegoli et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) as in the Compte section, with difference in the Uralian Arc region (Tagarieva, \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). The increase in species of \u003cem\u003eIcriodus\u003c/em\u003e in the Compte section, which leads to a different biofacies, the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e, near to the end of the Frasnian, is also observed in several sections of North Gondwana (Africa), West Euramerica (North America), East Euramerica (Europe) and South China regions (Lazreq, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Morrow, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Huang and Gong, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Farabegoli et al, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The extinction associated with the Kellwasser Event(s) and the transgressive event followed by a sharply regression (Johnson et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e1985\u003c/span\u003e; Sandberg et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1988\u003c/span\u003e, Carmichael et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) marks the F/F and the lowermost Famennian, which coincides with the \u003cem\u003eIcriodus\u003c/em\u003e abundance (Sandberg et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Girard and Renaud, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). However, and due to the high condensation in the Compte section, the lowermost Famennian has not been identified in this section yet. The \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e\u0026ndash;\u003cem\u003emint. minuta\u003c/em\u003e interval is characterized by high relative proportions of \u003cem\u003eIcriodus\u003c/em\u003e resulting in successions of \u003cem\u003ePalmatolepis-Icriodus\u003c/em\u003e and \u003cem\u003eIcriodus-Palmatolepis\u003c/em\u003e biofacies, including a peak of \u003cem\u003eIcriodus\u003c/em\u003e. This is also observed in the East Euramerica (Europe), North Gondwana (Africa), South China and Iran regions (Sch\u0026uuml;lke, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Lazreq, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Sch\u0026uuml;lke, \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Bahrami et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Farabegoli et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The presence of icriodids is high in different beds of the succeeding \u003cem\u003ePalmatolepis crepida\u003c/em\u003e and \u003cem\u003ePa. termini\u003c/em\u003e zones in East Euramerica (Europe) (Sch\u0026uuml;lke, \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Sch\u0026uuml;lke and Popp, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). However, in the Compte section, the great abundance of the pelagic palmatolepid outnumbers other genera and causes that these two zones record exclusively the \u003cem\u003ePalamatolepis\u003c/em\u003e biofacies. Icriodids and palmatolepids alternate the highest abundance during the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e and the base of the \u003cem\u003ePa. gl. pectinata\u003c/em\u003e zones, with an icriodid peak in the latter level; similar record is observed in Sardinia (Corradini, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). From the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone to \u003cem\u003ePa. mg. marginifera\u003c/em\u003e Zone, the icriodids abundance decreases and Palmatolepid and Polygnathid biofacies are the dominant worldwide; however, in the Compte section, the last icriodid peak is recorded in the middle of the \u003cem\u003ePa. rhomboidea\u003c/em\u003e Zone; this peak is also recorded in several European regions, Sardinia (Corradini, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e), Carnic Alps (Farabegoli et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) and Montagne Noir (Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The different position of the \u003cem\u003eIcriodus\u003c/em\u003e peaks in the Compte section, may be caused by local conditions and sedimentary environments or the occupation of empty niches by \u003cem\u003eIcriodus\u003c/em\u003e (Corradini, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). During the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e\u0026ndash;\u003cem\u003emg. marginifera\u003c/em\u003e zones Palmatolepid and Polygnathid biofacies still are the dominant in the Compte section, similar to other regions in East Euramerica (Europe), Uralian Arc and South China (Corradini, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Tagarieva, \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Farabegoli et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e5.3. Global Events in the Compte section.\u003c/h2\u003e \u003cp\u003eAs aforementioned, the lithological expressions of the Late Frasnian\u0026ndash;Early Famennian Global Events are not recorded in the section Compte. Thus, the suggested position of them is based on the effects of these Events in the conodont faunas and in the corresponding stratigraphical position.\u003c/p\u003e \u003cp\u003eKellwasser Events.\u003c/p\u003e \u003cp\u003eDuring the end of the Frasnian biotical crisis, there are two different Global Events recognized worldwide, the Lower and Upper Kellwasser Events (Schindler, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e1990\u003c/span\u003e). The definition of these events was established in the Kellwasser Kalk section in the Harz Mountains, Germany, which are two dark shales levels separated by limestones (Schindler, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Buggisch, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1991\u003c/span\u003e). The Lower Kellwasser Event is recorded in the transition between FZ12 and FZ13a subzone and the Upper Kellwasser Event in the top of FZ13c subzone (Becker et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Hartenfels, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Both events would be related with the beginning of first order T\u0026ndash;R cycles (sharply transgressions followed by regressions) and anoxic events respectively (Becker, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1993b\u003c/span\u003e; Sandberg et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Becker et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In the Compte section the main lithology of the Late Frasnian consists of nodular and bedded limestones and, thus, differs with the typical Kellwasser black shales facies from Euramerica and Gondwana (Schindler, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Ziegler and Sandberg, \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Becker and House, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Lazreq, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Gereke et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Slightly above the base of FZ13b subzone in the Compte section (Bed 89, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e), the change from \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e to \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies would suggest a local regressive trend, which may be referred to as the \u003cem\u003elinguiformis\u003c/em\u003e regression that is placed before the Upper Kellwasser Event and is recorded worldwide (Sandberg et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). This polygnathid increase recorded during the \u003cem\u003elinguiformis\u003c/em\u003e regression is similar to the augment observed in different sections from South China (Huang and Gong, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Chang et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). At the top of FZ13b the transgressive trend identified by a peak of palmatolepids (top of Bed 91, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e) could be interpreted as a local Event, close in time to the Upper Kellwasser Global Event. \u003cem\u003ePolygnathus decorosus\u003c/em\u003e becomes extinct in this interval and \u003cem\u003ePolygnathus lodinensis\u003c/em\u003e, \u003cem\u003ePalmatolepis boogaardi\u003c/em\u003e, \u003cem\u003eAncyrognathus asymmetricus\u003c/em\u003e, \u003cem\u003ePolygnathus webbi\u003c/em\u003e, \u003cem\u003ePalmatolepis juntianensis\u003c/em\u003e and \u003cem\u003eAncyrognathus amana\u003c/em\u003e are extinct in the base of FZ13c in Compte section (sample CP/92a). Typical Frasnian conodonts become extinct at the top of FZ13c subzone (upper part of Bed 92): \u003cem\u003eAncyrodella curvata\u003c/em\u003e, \u003cem\u003ePalmatolepis winchelli\u003c/em\u003e, \u003cem\u003ePalmatolepis bogartensis\u003c/em\u003e and \u003cem\u003eAncyrognathus asymmetricus\u003c/em\u003e. The extinction of many conodont taxa and the rise of icriodids indicating regressive trend, would indicate the Upper Kellwasser Event at the top of FZ13c.\u003c/p\u003e \u003cp\u003eOn the other hand, various authors suggest that the Upper Kellwasser interval is recorded earlier, slightly below the base of the Famennian. In South China the Upper Kellwasser Event might be formed by a transgressive trend positioned between the top of FZ13b and FZ13c; it was identified by microfacies analysis and high abundance of \u003cem\u003ePalmatolepis\u003c/em\u003e (Zhang, 2019). Subsequently, Farabegoli et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) divided the Upper Kellwasser extinction events in two phases. In the first phase several species of \u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003ePolygnathus\u003c/em\u003e, \u003cem\u003eAncyrodella\u003c/em\u003e and \u003cem\u003eAncyrognathus\u003c/em\u003e became extinct at the top of FZ13b. In the second phase all \u003cem\u003eAncyrodella\u003c/em\u003e and \u0026ldquo;manticolepids\u0026rdquo; \u003cem\u003ePalmatolepis\u003c/em\u003e, except \u003cem\u003ePalmatolepis ultima\u003c/em\u003e became extinct at the top of FZ13c.\u003c/p\u003e \u003cp\u003eNehden Event.\u003c/p\u003e \u003cp\u003eThe Nehden Event is a long\u0026ndash;term adaptative radiation process, correlated with a regressive trend rather than an extinction Global Event (Becker, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1993b\u003c/span\u003e; House, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). Walliser (\u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e1985\u003c/span\u003e; \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e1996\u003c/span\u003e) proposed the name \u003cem\u003eCheiloceras\u003c/em\u003e Event, due to the typical record of cheiloceratids ammonoids. During this Event, besides this radiation, other organisms as rhynchonellids brachiopods and palmatolepid conodonts proliferates (Becker, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1993a\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003eb\u003c/span\u003e; Huang et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). This conodont bloom is under discussion, either as a gradual biodiversification (Sch\u0026uuml;lke, \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1995\u003c/span\u003e, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; House, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Huang et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), or an abrupt biodiversification event (Sch\u0026uuml;lke and Popp, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Girard et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The sedimentary expression is characterized by black shales related with the transgressive trend in Western Europe (Becker, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1993b\u003c/span\u003e; Becker et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). However, and due to is limitation to local areas (Huang et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), the timing, impact order and magnitude of this event is still unclear. The duration of this event is within the \u003cem\u003ePalmatolepis termini\u003c/em\u003e and \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e zones (Becker et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) with a maximum flooding related with a maximum of pelagic black shales sedimentation in the top of the \u003cem\u003ePalmatolepis termini\u003c/em\u003e Zone and the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone (Becker et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Hartenfels, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). In the Compte section, there are neither evidence of \u0026ldquo;Nehden black shales\u0026rdquo; nor ammonoids radiation. However, the conodont data suggest a prolonged transgressive trend during the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e zones interval with the proliferation of palmatolepid biofacies alternating with \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e biofacies in the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone. A bloom of \u003cem\u003ePalmatolepis\u003c/em\u003e (98%) is recorded at the top of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone (Bed 104, sample CP/104b, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which suggests a maximum flooding of the Nehden Event. This transgressive trend interval suggests the extension of the Nehden Event up to the top of \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone in the Compte section. Similar timing is observed in the Lali section in South China with a peak of palmatolepids in the upper part of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone (Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e, Fig.\u0026nbsp;7). Different timing is documented in the Yangdi section, South China, which is subdivided into two Nehden Events (Huang et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), located earlier, within the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e Zone and among \u003cem\u003ePalmatolepis termini\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e zones respectively.\u003c/p\u003e \u003cp\u003eCondroz events.\u003c/p\u003e \u003cp\u003eAfter the Nehden transgressive Event, two abrupt regressive events widely recorded called Condroz Events, took place within the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e and \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones (Becker, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1993b\u003c/span\u003e; Sch\u0026uuml;lke and Popp, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Becker et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). These events started coinciding with the disappearance of the \u003cem\u003eCheiloceras\u003c/em\u003e shales (Sch\u0026uuml;lke and Popp, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2005\u003c/span\u003e) and the global regressive tendency. a Rich conodont fauna, specially \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e and a short regressive trend (Hartenfels et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Hartenfels, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) occur between these two regressive events, within the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone. However, these events do not have a significant impact on conodonts (Hartenfels, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). The change of the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e to the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in Bed 109 (sample CP/109b, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e), within the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone, suggests an abrupt regressive trend that can be aligned with the Lower Condroz Event. We accept that the \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is shallower than the \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e sensu Corradini (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). During the lower part of the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone, a bloom of \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e in the Compte section (Barrera-Lahoz et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2025\u003c/span\u003e, Table\u0026nbsp;2) similar to the one in Tafilalt (Hartenfels et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) is recorded. After the Lower Condroz Event, a transgressive trend is recognized by the appearance of the \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in the transition from the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e to \u003cem\u003ePal. gr. gracilis\u003c/em\u003e zones. The Upper Condroz Event is recognized in the Compte section at the base of Bed 113 (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e3\u003c/span\u003e), within the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone, corresponding with a short income of the \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies within the overall \u003cem\u003ePalmatolepis-Polygnathus\u003c/em\u003e biofacies.\u003c/p\u003e \u003c/div\u003e"},{"header":"6 Conclusions","content":"\u003cp\u003eThe Compte section yields a rich conodont fauna showing different faunal events and compositional changes. Five conodont biofacies are recognized in the Compte section: \u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e, \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e and \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e; they provide essential information about faunistic fluctuations and can be used as a proxy for recognizing eustatic changes.\u003c/p\u003e \u003cp\u003eThe \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is mainly located in the FZ13b subzone, the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e to the \u003cem\u003ePalmatolepis termini\u003c/em\u003e zones, the lower and upper parts of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone, the base of the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone, the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e\u0026ndash;\u003cem\u003egr. gracilis\u003c/em\u003e zones transition and in the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e Zone.\u003c/p\u003e \u003cp\u003eThe \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e biofacies is recorded mainly in the FZ13b and FZ13c subzones, the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e Zone and the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e Zone.\u003c/p\u003e \u003cp\u003eThe \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is placed within the FZ13a and FZ13b subzones, the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e and the \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones.\u003c/p\u003e \u003cp\u003eThe \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies is set at the top of the FZ13c subzone, within the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e, the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e and at the base of the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eThe new \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies, is pinpointed by three sharply peaks of \u003cem\u003eIcriodus\u003c/em\u003e in the \u003cem\u003ePalmatolepis mint. minuta\u003c/em\u003e, \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e and \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e zones.\u003c/p\u003e \u003cp\u003eComparing the distribution in the Compte section with other regions, the conodont biofacies distribution shows similarities and discrepancies: during the FZ13a\u0026ndash;b interval, polygnathids are also abundant in different sections in Poland, Italy and China (Matyja, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Farabegoli et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The increase in the abundance of icriodids and ancyrodellids is also recorded in these sections as well as in the Compte section. The F/F boundary is characterized by a peak of \u003cem\u003eIcriodus\u003c/em\u003e related with a maximum sea\u0026ndash;level fall. However, and because of the high condensation, the first Famennian conodont zone identified in the Compte section is the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e. The high proportion of \u003cem\u003eIcriodus\u003c/em\u003e through the \u003cem\u003ePalmatolepis del. platys\u003c/em\u003e\u0026ndash;\u003cem\u003emint. minuta\u003c/em\u003e interval is comparable with the records in different European, African and Asian sections. However, the relative abundance of icriodids during the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e\u0026ndash;\u003cem\u003etermini\u003c/em\u003e zones interval in Europe, contrasts with the dominant pelagic \u003cem\u003ePalmatolepis\u003c/em\u003e biofacies in the Compte section. Another icriodid peaks are reported in the \u003cem\u003ePalmatolepis gl. pectinata\u003c/em\u003e and \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e zones. Then, the dominance of palmatolepids during the \u003cem\u003ePalmatolepis mg. marginifera\u003c/em\u003e Zone is broadly similar within the different regions.\u003c/p\u003e \u003cp\u003eThe interpretation of the conodont biofacies allows recognition of possible eustatic trends and Global Events. During the end of the Frasnian, a regressive trend is recorded at the base of FZ13b that might be referred to the \u003cem\u003elinguiformis\u003c/em\u003e regression. The Upper Kellwasser Event is located in the upper part of the Comabella Fm. (Bed 91) in FZ13c subzone by the extinction of different Frasnian conodonts and the regressive trend at the F\u0026ndash;F boundary The Nehden adaptative Event can be located during the \u003cem\u003ePalmatolepis termini\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e zones with a maximum flooding at the top of the \u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e Zone. Within the La Mena Fm., the Condroz Events are recognized by two marked regressive trends pointed by conodont biofacies changes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCorresponding author\u003c/h2\u003e\n\u003cp\u003eH\u0026eacute;ctor BARRERA-LAHOZ. [email protected]\u003c/p\u003e\n\u003ch2\u003eCompliance with ethical standards\u003c/h2\u003e\n\u003cp\u003eConflict of interest: The authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eJ. C-L is supported by Maria Zambrano Grant (MIU Next Generation EU, ZA21-005) and Jos\u0026eacute; Castillejo Fellowship (MICCIN-MIU, CAS22/00148). H. B-L is supported by Sociedad Espa\u0026ntilde;ola de Paleontolog\u0026iacute;a. J. C-L is supported by UCM Research Grant PR 12/24-31569.\u003c/p\u003e\n\u003ch2\u003eAcknowledgements\u003c/h2\u003e\n\u003cp\u003eThis work is supported by the UCM Research Grant PR 12/24-31569. J. C-L is supported by Maria Zambrano Grant (MIU Next Generation EU, ZA21-005) and Jos\u0026eacute; Castillejo Fellowship (MICCIN-MIU, CAS22/00148). H. B-L is supported by Sociedad Espa\u0026ntilde;ola de Paleontolog\u0026iacute;a.\u003c/p\u003e\n\u003cp\u003eThis report represents a contribution to the Project IGCP-652 of UNESCO and, in addition, it conforms a contribution of the research groups GIUV2017-395, GEO-TRANSFER E32 17R and PERIGONDWANA UCM 910231. We also thank the facilities provided by the UNESCO Global Geopark Or\u0026iacute;gens to carry out our work.\u003c/p\u003e\n\u003ch2\u003eData availability statement\u003c/h2\u003e\n\u003cp\u003eAll data and materials that provide the research results are available within this article and extended in Barrera-Lahoz et al. (\u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e). The conodont remains which support the article data are housed in \u0026ldquo;Department of Botany and Geology\u0026rdquo; in University of Valencia, Burjasot, Spain.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBahrami, A., Parast, A., Boncheva, I., \u0026amp; Yazdi, M. (2020). Late Devonian (Famennian) conodonts from Baqer-Abad section, northeast Isfahan province, Central Iran. \u003cem\u003eBolet\u0026iacute;n de la Sociedad Geol\u0026oacute;gica Mexicana\u003c/em\u003e, \u003cem\u003e72\u003c/em\u003e(2), A100619. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.18268/BSGM2020v72n2a100619\u003c/span\u003e\u003cspan address=\"10.18268/BSGM2020v72n2a100619\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarnolas, A., \u0026amp; Pujalte, V. (2004). Cordillera Pirenaica. Definici\u0026oacute;n, l\u0026iacute;mites y divisi\u0026oacute;n. In J. A. Vera (Ed.), \u003cem\u003eGeolog\u0026iacute;a de Espa\u0026ntilde;a\u003c/em\u003e (pp. 233\u0026ndash;240). SGE-IGME.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarrera-Lahoz, H., Valenzuela-R\u0026iacute;os, J. I., \u0026amp; Liao, J. C. (2024). Famennian conodont assemblage in the Compte section (Upper Devonian, Central Pyrenees) and its comparison with Eurasian sequences. \u003cem\u003eSpanish Journal of Palaeontology\u003c/em\u003e, \u003cem\u003e39\u003c/em\u003e(1), 33\u0026ndash;70. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7203/sjp.28695\u003c/span\u003e\u003cspan address=\"10.7203/sjp.28695\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarrera-Lahoz, H., Valenzuela-R\u0026iacute;os, J. I., \u0026amp; Liao, J-C. (2025). Lower and middle Famennian (Upper Devonian) conodont biostratigraphy from Compte section (Central Pyrenees, Spain). In A. Munkhjargal, K. Mende, J. Lu, \u0026amp; U. Linnemann (Eds.), \u003cem\u003eSpecial contributions in honour of Peter K\u0026ouml;nigshof. Palaeobiodiversity and Palaeoenvironments\u003c/em\u003e, 105(1). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12549-025-00642-9\u003c/span\u003e\u003cspan address=\"10.1007/s12549-025-00642-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBecker, R. T. (1993a). Stratigraphische Gliederung und Ammonoideen-Faunen im Nehdenium (Oberdevon II) von Europa und Nord-Afrika. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e155\u003c/em\u003e, 1\u0026ndash;405.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBecker, R. T. (1993b). Anoxia, eustatic changes, and Upper Devonian to lowermost Carboniferous global ammonoid diversity. In M. R. House (Ed.), \u003cem\u003eThe Ammonoidea: Environment, ecology and evolutionary change\u003c/em\u003e. \u003cem\u003eSystematic Association, Special Volume, 47\u003c/em\u003e, 115\u0026ndash;163.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBecker, R. T., \u0026amp; House, M. R. (1994). Kellwasser Events and goniatite successions in the Devonian of the Montagne Noire with comments on possible causations. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e169\u003c/em\u003e, 45\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBecker, R. T., \u0026amp; House, M. R. (1997). Sea\u0026ndash;level changes in the Upper Devonian of the Canning Basin, western Australia. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e199\u003c/em\u003e, 129\u0026ndash;146.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBecker, R. T., Hartenfels, S., Helling, S., \u0026amp; Schreiber, G. (2016). The Nehden Goniatite Shale (lower Famennian, Brilon Reef Komplex, NE Rhenish Massif). In R. T. Becker, S. Hartenfels, P. Konigshof, \u0026amp; S. Helling (Eds.). Middle Devonian to Lower Carboniferous stratigraphy, facies, and bioevents in the Rhenish Massif, Germany \u0026ndash; an IGCP 596 Guidebook. \u003cem\u003eM\u0026uuml;nstersche Forschungen zur Geologie und Pal\u0026auml;ontologie, 108\u003c/em\u003e, 179\u0026ndash;195.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBecker, R. T., Marshall, J. E. A., Da Silva, A. C., Agterberg, F. P., Gradstein, F. M., \u0026amp; Ogg, J. G. (2020). The Devonian Period. In: Agterberg, F.P., Gradstein, F.M., Ogg, J.G. (Eds.), \u003cem\u003eThe Geologic Time Scale\u003c/em\u003e (2nd vol. pp. 733\u0026ndash;810). Elsevier. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/B978-0-12-824360-2.00022-X\u003c/span\u003e\u003cspan address=\"10.1016/B978-0-12-824360-2.00022-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoersma, K. T. (1973). Devonian and Lower Carboniferous conodont biostratigraphy, Spanish Central Pyrenees. \u003cem\u003eLeidse Geologische Mededelingen\u003c/em\u003e, \u003cem\u003e49\u003c/em\u003e(2), 303\u0026ndash;377.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBuggisch, W. (1991). The global Frasnian-Famennian\u0026raquo; Kellwasser Event \u0026laquo;. \u003cem\u003eGeologische Rundschau\u003c/em\u003e, \u003cem\u003e80\u003c/em\u003e, 49\u0026ndash;72. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/BF01828767\u003c/span\u003e\u003cspan address=\"10.1007/BF01828767\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarmichael, S. K., Waters, J. A., K\u0026ouml;nigshof, P., Suttner, T. J., \u0026amp; Kido, E. (2019). Paleogeography and paleoenvironments of the Late Devonian Kellwasser event: A review of its sedimentological and geochemical expression. \u003cem\u003eGlobal and Planetary Change\u003c/em\u003e, \u003cem\u003e183\u003c/em\u003e, 102984. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.gloplacha.2019.102984\u003c/span\u003e\u003cspan address=\"10.1016/j.gloplacha.2019.102984\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChang, J., Bai, Z., Sun, Y., Peng, Y., Qin, S., \u0026amp; Shen, B. (2017). High resolution bio-and chemostratigraphic framework at the Frasnian\u0026ndash;Famennian boundary: implications for regional stratigraphic correlation between different sedimentary facies in South China. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e531\u003c/em\u003e, 108299. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2017.05.019\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2017.05.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCorradini, C. (1998). Famennian conodonts from two sections near Villasalto. \u003cem\u003eGiornale di Geologia\u003c/em\u003e, \u003cem\u003eseria\u003c/em\u003e 3\u003csup\u003ea\u003c/sup\u003e, \u003cem\u003eSpecial Issue\u003c/em\u003e. \u003cem\u003eSardinia Field Trip Guidebook\u003c/em\u003e, \u003cem\u003e60\u003c/em\u003e, 122\u0026ndash;135.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCorradini, C. (2003). Late Devonian (Famennian) conodonts from the Corona Mizziu Sections near Villasalto (Sardinia, Italy). \u003cem\u003ePalaeontographia Italica\u003c/em\u003e, \u003cem\u003e89\u003c/em\u003e, 65\u0026ndash;116.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDreesen, R., \u0026amp; Thorez, J. (1980). Sedimentary environments, conodont biofacies and paleoecology of the Belgian Famennian (Upper Devonian)-an approach. \u003cem\u003eAnnales de la Soci\u0026eacute;t\u0026eacute; g\u0026eacute;ologique de Belgique\u003c/em\u003e, \u003cem\u003e103\u003c/em\u003e, 97\u0026ndash;110.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFarabegoli, E., Perri, M. C., Spalletta, C., Joachimski, M. M., Andrew, A., \u0026amp; Pondrelli, M. (2023). Physical and biological events across the Frasnian-Famennian boundary (Late Devonian) in continuous oxic carbonate successions in the western Tethys (Carnic Alps of Italy and Austria). \u003cem\u003eBollettino della Societ\u0026agrave; Paleontologica Italiana\u003c/em\u003e, \u003cem\u003e62\u003c/em\u003e(2), 143\u0026ndash;217. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://dx.doi.org/10.4435/BSPI.2023.06\u003c/span\u003e\u003cspan address=\"10.4435/BSPI.2023.06\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGereke, M., Luppold, F. W., Piecha, M., Schindler, E., \u0026amp; Stoppel, D. (2014). Die Typlokalit\u0026auml;t der Kellwasser-Horizonte im Oberharz, Deutschland. \u003cem\u003eZeitschrift der Deutschen Gesellschaft f\u0026uuml;r Geowissenschaften\u003c/em\u003e, 145\u0026ndash;162.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirard, C., \u0026amp; Renaud, S. (2007). Quantitative conodont-based approaches for correlation of the Late Devonian Kellwasser anoxic events. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e250\u003c/em\u003e(1\u0026ndash;4), 114\u0026ndash;125. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2007.03.007\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2007.03.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirard, C., Klapper, G., \u0026amp; Feist, R. (2005). Subdivision of the terminal Frasnian linguiformis conodont Zone, revision of the correlative interval of Montagne Noire Zone 13, and discussion of stratigraphically significant associated trilobites. \u003cem\u003eDevelopments in Palaeontology and Stratigraphy\u003c/em\u003e, \u003cem\u003e20\u003c/em\u003e, 181\u0026ndash;198. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0920-5446(05)80007-X\u003c/span\u003e\u003cspan address=\"10.1016/S0920-5446(05)80007-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirard, C., Cornee, J. J., Corradini, C., Fravalo, A., \u0026amp; Feist, R. (2014). Palaeoenvironmental changes at Col des Tribes (Montagne Noire, France), a reference section for the Famennian of north Gondwana-related areas. \u003cem\u003eGeological Magazine\u003c/em\u003e, \u003cem\u003e151\u003c/em\u003e(5), 864\u0026ndash;884. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1017/S0016756813000927\u003c/span\u003e\u003cspan address=\"10.1017/S0016756813000927\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirard, C., Cornee, J. J., Charruault, A. L., Corradini, C., Weyer, D., Bartzsch, K., Joachimski, M., \u0026amp; Feist, R. (2017). Conodont biostratigraphy and palaeoenvironmental trends during the Famennian (Late Devonian) in the Thuringian Buschteich section (Germany). \u003cem\u003eNewsletters on Stratigraphy\u003c/em\u003e, \u003cem\u003e50\u003c/em\u003e(1), 71\u0026ndash;89. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1127/nos/2016/0318\u003c/span\u003e\u003cspan address=\"10.1127/nos/2016/0318\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirard, C., Cornee, J. J., Joachimski, M. M., Charruault, A. L., Dufour, A. B., \u0026amp; Renaud, S. (2020). Paleogeographic differences in temperature, water depth and conodont biofacies during the Late Devonian. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e549\u003c/em\u003e, 108852. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2018.06.046\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2018.06.046\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHartenfels, S. (2024). Upper Devonian to Mississippian global environmental change and impact on conodonts. \u003cem\u003ePalaeobiodiversity and Palaeoenvironments\u003c/em\u003e, 1\u0026ndash;54. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12549-024-00622-5\u003c/span\u003e\u003cspan address=\"10.1007/s12549-024-00622-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHartenfels, S., Becker, R. T., Aboussalam, Z. S., Hassani, E., Baider, A., Fischer, L., T., \u0026amp; Stichling, S. (2013). The Upper Devonian at El Khraouia (southern Tafilalt). In R. T. Becker, A. El Hassani, \u0026amp; A. Tahiri (Eds.). International Field Symposium the Devonian and Lower Carboniferous of northern Gondwana. \u003cem\u003eDocument de l\u0026rsquo;Institut Scientifique, Rabat, 27\u003c/em\u003e, 41\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHartevelt, J. J. A. (1970). Geology of the upper Segre and Valira valleys, central Pyrenees, Andorra/Spain. \u003cem\u003eLeidse Geologische Mededelingen\u003c/em\u003e, \u003cem\u003e45\u003c/em\u003e(1), 167\u0026ndash;236.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHouse, M. R. (2002). Strength, timing, setting and cause of mid-Palaeozoic extinctions. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e181\u003c/em\u003e(1\u0026ndash;3), 5\u0026ndash;25. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0031-0182(01)00471-0\u003c/span\u003e\u003cspan address=\"10.1016/S0031-0182(01)00471-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang, C., \u0026amp; Gong, Y. (2016). Timing and patterns of the Frasnian\u0026ndash;Famennian event: Evidences from high-resolution conodont biostratigraphy and event stratigraphy at the Yangdi section, Guangxi, South China. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e448\u003c/em\u003e, 317\u0026ndash;338. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2015.10.031\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2015.10.031\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang, C., Song, H., Zhai, M., Pu, T., \u0026amp; Han, M. (2024). Timing and pattern of the Devonian Nehden event: Implication for the biotic recovery following the F\u0026ndash;F extinction event. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e648\u003c/em\u003e, 112276. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2024.112276\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2024.112276\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInstitut Cartogr\u0026agrave;fic i Geol\u0026ograve;gic de Catalunya (2024, October 28). \u003cem\u003eMapa Geol\u0026ograve;gic de Catalunya 1:25000\u003c/em\u003e. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://betaportal.icgc.cat/visor/client_utfgrid_geo.html\u003c/span\u003e\u003cspan address=\"https://betaportal.icgc.cat/visor/client_utfgrid_geo.html\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJohnson, J. G., Klapper, G., \u0026amp; Sandberg, C. A. (1985). Devonian eustatic fluctuations in Euramerica. \u003cem\u003eGeological Society of America Bulletin\u003c/em\u003e, \u003cem\u003e96\u003c/em\u003e(5), 567\u0026ndash;587. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1130/0016-7606(1985)96\u0026lt;567:DEFIE\u0026gt;2.0.CO;2\u003c/span\u003e\u003cspan address=\"10.1130/0016-7606(1985)96%3C567:DEFIE%3E2.0.CO;2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKlapper, G. (1989). The Montagne Noire Frasnian (Upper Devonian) Conodont Succession. In N. J. McMillan, A. F. Embry, \u0026amp; D. J. Glass (Eds.), Devonian of the World. \u003cem\u003eCanadian Society of Petroleum Geologists\u003c/em\u003e, \u003cem\u003eMemoir\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(III), 449\u0026ndash;468 [imprint 1988].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKlapper, G. (2007). Conodont taxonomy and the recognition of the Frasnian/Famennian (Upper Devonian) stage boundary. \u003cem\u003eStratigraphy\u003c/em\u003e, \u003cem\u003e4\u003c/em\u003e(1), 67\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKlapper, G., \u0026amp; Kirchgasser, W. T. (2016). Frasnian Late Devonian conodont biostratigraphy in New York: graphic correlation and taxonomy. \u003cem\u003eJournal of Paleontology\u003c/em\u003e, \u003cem\u003e90\u003c/em\u003e(3), 525\u0026ndash;554. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1017/jpa.2015.70\u003c/span\u003e\u003cspan address=\"10.1017/jpa.2015.70\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLazreq, N. (1992). The upper Devonian of M\u0026rsquo;rirt (Morocco). \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e154\u003c/em\u003e, 107\u0026ndash;123.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLazreq, N. (1999). Biostratigraphie des conodontes du Giv\u0026eacute;tien au Famennien du Maroc central \u0026ndash; Biofaci\u0026egrave;s et \u0026eacute;v\u0026eacute;nement Kellwasser. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e214\u003c/em\u003e, 1\u0026ndash;111.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiao, J. C. (2014). \u003cem\u003eBioestratigraf\u0026iacute;a con conodontos del givetiense (Dev\u0026oacute;nico Medio) del Pirineo Central\u003c/em\u003e (PhD Thesis, Universidad Complutense de Madrid).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiao, J. C., \u0026amp; Valenzuela- R\u0026iacute;os, J. I. (2008). Givetian and early Frasnian conodonts from the Compte section (Middle\u0026ndash;Upper Devonian, Spanish Central Pyrenees). \u003cem\u003eGeological Quaterly\u003c/em\u003e, \u003cem\u003e52\u003c/em\u003e(1), 1\u0026ndash;18.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiao, J. C., \u0026amp; Valenzuela-R\u0026iacute;os, J. I. (2017). Givetian to Famennian conodonts (Middle\u0026ndash;Upper Devonian) at CP section. \u003cem\u003eInternational Conodont Symposium 4. Progress on Conodont investigation\u003c/em\u003e (pp. 99\u0026ndash;105). Valencia.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiao, J. C., K\u0026ouml;nigshof, P., Valenzuela-Rios, J. I., \u0026amp; Schindler, E. (2008). Depositional environment interpretation and development of the Renanu\u0026eacute; section (Upper Eifelian-Lower Frasnian; Pyrenees, N. Spain). \u003cem\u003eBulletin of Geosciences\u003c/em\u003e, \u003cem\u003e83\u003c/em\u003e, 481\u0026ndash;490. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3140/bull.geosci.2008.04.481\u003c/span\u003e\u003cspan address=\"10.3140/bull.geosci.2008.04.481\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eL\u0026uuml;ddecke, F., Hartenfels, S., \u0026amp; Becker, R. T. (2017). Conodont biofacies of a monotonous middle Famennian pelagic carbonate succession (Upper Ballberg Quarry, northern Rhenish Massif). \u003cem\u003ePalaeobiodiversity and Palaeoenvironments\u003c/em\u003e, \u003cem\u003e97\u003c/em\u003e, 591\u0026ndash;613. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12549-017-0288-x\u003c/span\u003e\u003cspan address=\"10.1007/s12549-017-0288-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMart\u0026iacute;nez-P\u0026eacute;rez, C., \u0026amp; Valenzuela-R\u0026iacute;os, J. I. (2014). New Lower Devonian Polygnathids (Conodonta) from the Spanish Central Pyrenees, with comments on the early radiation of the group. \u003cem\u003eJournal of Iberian Geology\u003c/em\u003e, \u003cem\u003e40\u003c/em\u003e(1), 141\u0026ndash;155. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5209/rev_JIGE.2014.v40.n1.44095\u003c/span\u003e\u003cspan address=\"10.5209/rev_JIGE.2014.v40.n1.44095\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMart\u0026iacute;nez-P\u0026eacute;rez, C., Valenzuela-R\u0026iacute;os, J. I., Navas-Parejo, P., Liao, J. C., \u0026amp; Botella, H. (2011). Emsian (Lower Devonian) Polygnathids (Conodont) succession in the Spanish Central Pyrenees. \u003cem\u003eJournal of Iberian Geology\u003c/em\u003e, \u003cem\u003e37\u003c/em\u003e(1), 45\u0026ndash;64. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5209/rev_JIGE.2011.v37.n1.4\u003c/span\u003e\u003cspan address=\"10.5209/rev_JIGE.2011.v37.n1.4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMatyja, H. (1993). Upper Devonian of Western Pomerania. \u003cem\u003eActa Geologica Polonica\u003c/em\u003e, \u003cem\u003e43\u003c/em\u003e(1/2), 27\u0026ndash;94.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMatyja, H., \u0026amp; Narkiewicz, M. (1992). Conodont biofacies succession near the Frasnian/Famennian boundary: some Polish examples. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e154\u003c/em\u003e, 125\u0026ndash;147.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcGhee, G. R. (2013). \u003cem\u003eWhen the Invasion of Land Failed: The Legacy of the Devonian Extinctions\u003c/em\u003e. Columbia University.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcGhee, G. R., Clapham, M. E., Sheehan, P. M., Bottjer, D. J., \u0026amp; Droser, M. L. (2013). A new ecological-severity ranking of major Phanerozoic biodiversity crises. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e370\u003c/em\u003e, 260\u0026ndash;270. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2012.12.019\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2012.12.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMey, P. H. W. (1967a). The geology of the upper Ribagorzana and Baliera valleys, Central Pyrenees, Spain. \u003cem\u003eLeidse Geologische Mededelingen\u003c/em\u003e, \u003cem\u003e41\u003c/em\u003e, 153\u0026ndash;220.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMey, P. H. W. (1967b). Evolution of the Pyrenean Basins during the Late Paleozoic. \u003cem\u003eInternational Symposium on the Devonian System\u003c/em\u003e (pp. 1157\u0026ndash;1166). Calgary.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMorrow, J. (2000). Shelf-to-Basin Lithofacies and Conodont Paleoecology across Frasian\u0026ndash;Famennian (F\u0026ndash;F, mid\u0026ndash;Late Devonian) Boundary, Central Great Basin (Western U.S.A). \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e219\u003c/em\u003e, 1\u0026ndash;57.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eS\u0026aacute;nchez de Posada, L. C., Sanz-L\u0026oacute;pez, J., \u0026amp; Gozalo, R. (2008). Ostracod and conodont faunal changes across the Frasnian\u0026ndash;Famennian (Devonian) boundary at Els Castells, Spanish central Pyrenees. \u003cem\u003eRevue de Micropal\u0026eacute;ontologie\u003c/em\u003e, \u003cem\u003e51\u003c/em\u003e(3), 205\u0026ndash;219. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.revmic.2007.06.001\u003c/span\u003e\u003cspan address=\"10.1016/j.revmic.2007.06.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSandberg, C. A. (1976). Conodont biofacies of the Late Devonian \u003cem\u003ePolygnathus styriacus\u003c/em\u003e Zone in western United States. In C.R. Barner (Ed.), Conodont paleoecology. \u003cem\u003eGeological Association of Canada\u003c/em\u003e, \u003cem\u003eSpecial Paper\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e, 171\u0026ndash;186.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSandberg, C. A., \u0026amp; Dreesen, R. (1984). Late Devonian icriodontid biofacies models and alternate shallow-water conodont zonation. In D.L. Clark (Ed.), Conodont biofacies and provincialism. \u003cem\u003eGeological Society of America\u003c/em\u003e, \u003cem\u003eSpecial Papers\u003c/em\u003e, \u003cem\u003e196\u003c/em\u003e, 143\u0026ndash;179.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSandberg, C. A., Ziegler, W., Dreesen, R., \u0026amp; Buttler, J. L. (1988). Late Frasnian mass extinction: conodont event stratigraphy, global changes, and possible causes. In W. Ziegler (Ed.), 1st International Conodont Conference and 5th European Conodont Symposium (ECOS V) Contributions 1. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e102\u003c/em\u003e, 263\u0026ndash;307.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSandberg, C. A., Hasenmueller, N. R., \u0026amp; Rexroad, C. B. (1994). Conodont biochronology, biostratigraphy, and biofacies of Upper Devonian part of New Albany Shale, Indiana. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e168\u003c/em\u003e, 227\u0026ndash;253.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSandberg, C., Morrow, J. R., \u0026amp; Ziegler, W. (2002). Late Devonian sea-level changes, catastrophic events, and mass extinctions. \u003cem\u003eGeological Society of America Special Papers\u003c/em\u003e, \u003cem\u003e356\u003c/em\u003e, 473\u0026ndash;487. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1130/0-8137-2356-6.473\u003c/span\u003e\u003cspan address=\"10.1130/0-8137-2356-6.473\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSanz-L\u0026oacute;pez, J., Garc\u0026iacute;a-L\u0026oacute;pez, S., \u0026amp; Montesinos L\u0026oacute;pez, J. R. (1999). Conodontos del Frasniense superior y Fameniense inferior de la Formaci\u0026oacute;n Carda\u0026ntilde;o (Unidad del Cildar-Mont\u0026oacute;, Dominio Palentino, Zona Cant\u0026aacute;brica). \u003cem\u003eSpanish Journal of Palaeontology\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(1), 25\u0026ndash;35. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7203/sjp.22779\u003c/span\u003e\u003cspan address=\"10.7203/sjp.22779\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSavoy, L. E., \u0026amp; Harris, A. G. (1993). Conodont biofacies in a ramp to basin setting (latest Devonian and earliest Carboniferous) in the Rocky Mountains of southernmost Canada and northern Montana. \u003cem\u003eU. S. Geological Survey\u003c/em\u003e. \u003cem\u003eOpen-File Report\u003c/em\u003e, 93\u0026ndash;184, 1\u0026ndash;37.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchmidt, H., \u0026amp; G\u0026ouml;ttingen (1931). \u003cem\u003emath\u0026ndash;phys Kl\u003c/em\u003e, 3 (5, 1\u0026ndash;85.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchindler, E. (1990). Die Kellwasser-Krise. \u003cem\u003eG\u0026ouml;ttinger Arbeiten zur Geologie und Pal\u0026auml;ontologie\u003c/em\u003e, \u003cem\u003e46\u003c/em\u003e, 1\u0026ndash;115.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSch\u0026uuml;lke, I. (1995). Evolutive Prozesse bei Palmatolepis in der fruhen Famenne-Stufe (Conodonta, Ober-Devon). \u003cem\u003eG\u0026ouml;ttinger Arbeiten zur Geologie und Pal\u0026auml;ontologie\u003c/em\u003e, \u003cem\u003e67\u003c/em\u003e, 1\u0026ndash;108.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSch\u0026uuml;lke, I. (1999). Conodont multielement reconstruction from the Early Famennian (Late Devonian) of the Montagne Noire (Southern France). \u003cem\u003eGeologica et Palaeontologica\u003c/em\u003e, \u003cem\u003e3\u003c/em\u003e, 1\u0026ndash;123.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSch\u0026uuml;lke, I. (2003). Famennian conodont biodiversity cycles. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e242\u003c/em\u003e, 225\u0026ndash;238.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSch\u0026uuml;lke, I., \u0026amp; Popp, A. (2005). Microfacies development, sea-level change, and conodont stratigraphy of Famennian mid-to deep platform deposits of the Beringhauser Tunnel section (Rheinisches Schiefergebirge, Germany). \u003cem\u003eFacies\u003c/em\u003e, \u003cem\u003e50\u003c/em\u003e, 647\u0026ndash;664. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10347-004-0041-6\u003c/span\u003e\u003cspan address=\"10.1007/s10347-004-0041-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSeddon, G. (1970). Frasnian conodonts from the Sadler Ridge-Bugle Gap area, Canning Basin, Western Australia. \u003cem\u003eJournal of the Geological Society of Australia\u003c/em\u003e, \u003cem\u003e10\u003c/em\u003e, 723\u0026ndash;753.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSeddon, G., \u0026amp; Sweet, W. C. (1971). An ecologic model for conodonts. \u003cem\u003eJournal of Paleontology\u003c/em\u003e, \u003cem\u003e45\u003c/em\u003e(5), 869\u0026ndash;880.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilv\u0026eacute;rio, G. G., Valenzuela-R\u0026iacute;os, J. I., \u0026amp; Liao, J. C. (2021). Upper Frasnian and Lower Famennian (Upper Devonian) conodonts of the Compte section (Spanish Central Pyrenees). \u003cem\u003eSpanish Journal of Palaeontology\u003c/em\u003e, \u003cem\u003e36\u003c/em\u003e(2), 205\u0026ndash;220. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7203/sjp.36.2.21950\u003c/span\u003e\u003cspan address=\"10.7203/sjp.36.2.21950\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpalletta, C., Perri, M. C., Over, D. J., \u0026amp; Corradini, C. (2017). Famennian (Upper Devonian) conodont zonation: revised global standard. \u003cem\u003eBulletin of Geosciences\u003c/em\u003e, \u003cem\u003e92\u003c/em\u003e(1), 31\u0026ndash;57. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3140/bull.geosci.1623\u003c/span\u003e\u003cspan address=\"10.3140/bull.geosci.1623\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSuttner, T. J., Kido, E., Ariunchimeg, Y., Sersmaa, G., Waters, J. A., Carmichael, S. K., Batchelor, C. J., Ariuntogos, M., Huškov\u0026aacute;, A., Slav\u0026iacute;k, L., Valenzuela-R\u0026iacute;os, J. I., Liao, J. C., \u0026amp; Gatovsky, Y. A. (2020). Conodonts from Late Devonian Island arc settings (Baruunhuurai Terrane, western Mongolia). \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e549\u003c/em\u003e, 109099. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2019.03.001\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2019.03.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTagarieva, R. C. (2013). Conodont biodiversity of the Frasnian-Famennian boundary interval (Upper Devonian) in the Southern Urals. \u003cem\u003eBulletin of Geosciences\u003c/em\u003e, \u003cem\u003e88\u003c/em\u003e(2), 297\u0026ndash;314. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3140/bull.geosci.1344\u003c/span\u003e\u003cspan address=\"10.3140/bull.geosci.1344\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValenzuela-R\u0026iacute;os, J. I., \u0026amp; Liao, J. C. (2006). Annotations to Devonian Correlation Table, R 357\u0026ndash;360 di-ds 06: Spanish Central Pyrenees, southern part. \u003cem\u003eSenckenbergiana lethaea\u003c/em\u003e, \u003cem\u003e86\u003c/em\u003e, 105\u0026ndash;107. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/BF03043640\u003c/span\u003e\u003cspan address=\"10.1007/BF03043640\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValenzuela-R\u0026iacute;os, J. I., Chen, L., Mart\u0026iacute;nez-P\u0026eacute;rez, J. C., Castell\u0026oacute;, C., V., \u0026amp; Botella, H. (2005). Datos preliminares sobre los conodontos y restos de peces del Lochkoviense y \u0026iquest;Praguiense? (Dev\u0026oacute;nico Inferior) de Compte-I (Valle del Noguera Pallaresa, Pirineos). In: J.I. Valenzuela-R\u0026iacute;os; J.A. G\u0026aacute;mez y E. Li\u0026ntilde;\u0026aacute;n (Eds.), \u003cem\u003eMemorias de las VIII Jornadas Aragonesas de Paleontolog\u0026iacute;a: La cooperaci\u0026oacute;n Internacional en la Paleontolog\u0026iacute;a espa\u0026ntilde;ola. Homenaje al Profesor Peter Carls\u003c/em\u003e, 123\u0026ndash;136.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValenzuela-R\u0026iacute;os, J. I., Slav\u0026iacute;k, L., Liao, J. C., Calvo, H., Huškov\u0026aacute;, A., \u0026amp; Chadimov\u0026aacute;, L. (2015). The middle and upper Lochkovian (Lower Devonian) conodont successions in key peri‐Gondwana localities (Spanish Central Pyrenees and Prague Synform) and their relevance for global correlations. \u003cem\u003eTerra Nova\u003c/em\u003e, \u003cem\u003e27\u003c/em\u003e(6), 409\u0026ndash;415. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/ter.12172\u003c/span\u003e\u003cspan address=\"10.1111/ter.12172\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWalliser, O. H. (1985). Natural boundaries and Commission boundaries in the Devonian. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e75\u003c/em\u003e, 401\u0026ndash;408.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWalliser, O. H. (1996). Global Events in the Devonian and Carboniferous. In O. H. Walliser (Ed.), \u003cem\u003eGlobal Events and Event Stratigraphy in the Phanerozoic\u003c/em\u003e. Springer. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/978-3-642-79634-0_11\u003c/span\u003e\u003cspan address=\"10.1007/978-3-642-79634-0_11\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYazdi, M. (1999). Late Devonian\u0026ndash;Carboniferous conodonts from Eastern Iran. \u003cem\u003eRivista Italiana di Paleontologia e Stratigrafia\u003c/em\u003e, \u003cem\u003e105\u003c/em\u003e(2), 167\u0026ndash;200.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang, X. S., Over, D. J., Ma, K., \u0026amp; Gong, Y. (2019). Upper Devonian conodont zonation, sea-level changes and bio-events in offshore carbonate facies Lali section, South China. \u003cem\u003ePalaeogeography Palaeoclimatology Palaeoecology\u003c/em\u003e, \u003cem\u003e531\u003c/em\u003e, 109219. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.palaeo.2019.05.041\u003c/span\u003e\u003cspan address=\"10.1016/j.palaeo.2019.05.041\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZiegler, W. (1959). Conodonten aus Devon und Karbon S\u0026uuml;dwesteuropas und Bemerkungen zur bretonischen Faltung (Montagne Noire, Massiv Mounthoumet, Span. Pyren\u0026auml;en). \u003cem\u003eNeus Jahrbuch f\u0026uuml;r Geologie und Pal\u0026auml;eontologie Monatshefte\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e, 289\u0026ndash;309.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZiegler, W., \u0026amp; Sandberg, C. A. (1990). The Late Devonian Standard Conodont Zonation. \u003cem\u003eCourier Forschungsinstitut Senckenberg\u003c/em\u003e, \u003cem\u003e121\u003c/em\u003e, 1\u0026ndash;115.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZwart, H. J. (1979). The geology of the Central Pyrenees. \u003cem\u003eLeidse Geologische Mededelingen\u003c/em\u003e, \u003cem\u003e50\u003c/em\u003e(1), 1\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-iberian-geology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jibg","sideBox":"Learn more about [Journal of Iberian Geology](http://link.springer.com/journal/41513)","snPcode":"41513","submissionUrl":"https://www.editorialmanager.com/jibg/default2.aspx","title":"Journal of Iberian Geology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"conodont biofacies, eustatic trends, Kellwasser Events, Nehden Event, Condroz Events","lastPublishedDoi":"10.21203/rs.3.rs-6413435/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6413435/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDetailed studies on conodont biofacies from upper Frasnian to middle Famennian in the Compte section (Central Pyrenees area) allow recognition of different eustatic fluctuations and the Kellwasser, Nehden and Condroz events, as well. Five conodont biofacies have been identified: \u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003ePolygnathus\u003c/em\u003e, \u003cem\u003ePolygnathus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e, \u003cem\u003ePalmatolepis\u003c/em\u003e\u0026ndash;\u003cem\u003eIcriodus\u003c/em\u003e and the new \u003cem\u003eIcriodus\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis\u003c/em\u003e biofacies. The evolution of conodont biofacies during the end Frasnian reflects a sudden regressive episode at the base of FZ13b subzone and a maximum transgressive trend at the top of FZ13b subzone, which aligns with the Upper Kellwasser Event. The Kellwasser crisis reduces dramatically the conodont biodiversity, and during the lower Famennian, the conodont biodiversity recovers. A transgressive trend is recorded during the \u003cem\u003ePalmatolepis crepida\u003c/em\u003e\u0026ndash;\u003cem\u003ePalmatolepis gl. prima\u003c/em\u003e zone interval, which may be referred to as the Nehden Event. Within La Mena Formation two regressive trends are identified by sharp conodont biofacies changes in the \u003cem\u003ePalmatolepis rhomboidea\u003c/em\u003e and \u003cem\u003ePalmatolepis gr. gracilis\u003c/em\u003e zones. These two regressive trends correspond to the lower and upper Condroz Events respectively.\u003c/p\u003e","manuscriptTitle":"Frasnian–Famennian (Upper Devonian) conodont biofacies and Global Events in the Compte section (Central Pyrenees, Spain.)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-19 16:29:43","doi":"10.21203/rs.3.rs-6413435/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvited","content":"Journal of Iberian Geology","date":"2025-10-16T18:01:03+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-05-18T11:23:27+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-15T17:04:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-04-11T12:11:25+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Iberian Geology","date":"2025-04-09T11:40:13+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-iberian-geology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jibg","sideBox":"Learn more about [Journal of Iberian Geology](http://link.springer.com/journal/41513)","snPcode":"41513","submissionUrl":"https://www.editorialmanager.com/jibg/default2.aspx","title":"Journal of Iberian Geology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a973c104-1b75-45c5-849a-bb6d451e193f","owner":[],"postedDate":"May 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T16:00:49+00:00","versionOfRecord":{"articleIdentity":"rs-6413435","link":"https://doi.org/10.1007/s41513-026-00335-y","journal":{"identity":"journal-of-iberian-geology","isVorOnly":false,"title":"Journal of Iberian Geology"},"publishedOn":"2026-04-22 15:57:34","publishedOnDateReadable":"April 22nd, 2026"},"versionCreatedAt":"2025-05-19 16:29:43","video":"","vorDoi":"10.1007/s41513-026-00335-y","vorDoiUrl":"https://doi.org/10.1007/s41513-026-00335-y","workflowStages":[]},"version":"v1","identity":"rs-6413435","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6413435","identity":"rs-6413435","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}