Parasite diversity in sea turtles of the temperate SW Atlantic: a bridge between systematics and ecology

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This research focuses on the parasite diversity of two sea turtle species —the loggerhead Caretta caretta and leatherback Dermochelys coriacea sea turtles— in the temperate Southwest Atlantic, a region and species relatively understudied. Over a 15-year period (2008–2023), 30 sea turtles were sampled from the northern coast of Argentina. Through morphological and molecular tools, we identified five parasite species (the digeneans Pyelosomum renicapite and P. longiusculus , the nematodes Kathlania leptura and Sulcascaris sulcata and the leech Ozobranchus margoi ) in loggerheads; and two digeneans ( P. renicapite and O. amphiorchis ) in leatherbacks. All species constitute the first report of the parasite in Argentina, and O. amphiorchis represents a new host-parasite association for leatherbacks. Comparative biogeographic analysis using the Regional Management Unit framework revealed that parasites could reveal connectivity between RMUs, though there are several information gaps. Increasing parasite studies can help understand sea turtle feeding ecology, ontogenetic shift and health status, and thus enhance conservation strategies for sea turtles globally. loggerhead turtle leatherback turtle digenea nematoda Argentina Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Parasite studies can provide insights into major threats to global biodiversity, such as overexploitation, habitat fragmentation, and climate change among others (Gagne et al. 2022 ). In aquatic environments, these studies offer valuable information on critical aspects of host ecology, including feeding habits, migrations, and exposure to environmental contaminants and stressors (Marcogliese 2004 , 2023 ). Given the role of parasites in regulating host population (Marcogliese and Price 1997 ), such studies are particularly important for species of conservation concern. Sea turtles are a group of seven species listed in categories from Data Deficient to Critically Endangered (IUCN 2023). For most species, the life cycle includes an ontogenetic shift from oceanic to neritic habitats, as well as a transition from omnivorous, pelagic feeding behavior to a more specialized, benthic feeding behavior (Musick and Limpus 1997 ; Bolten 2003 ). Even though most species connect ocean regions separated by thousands of kilometers, individuals often remain in certain feeding areas long enough to become infected with parasites (Greiner 2013 ). Sea turtle’s parasites have received considerable attention over time (e.g. Luhman 1935 ; Lester et al. 1980 ; Santoro et al. 2020 ), with greater focus on parasite systematics (Hamann et al. 2010 ) compared to ecological studies. While parasites are quite well known for certain turtle species and areas (e.g. the green turtle Chelonia mydas has the largest number of parasite records worldwide, much of which come from the Northwest Atlantic; Greiner 2013 ), there are regions and species for which parasitological knowledge is still limited. Sea turtles are organized into Regional Management Units (RMUs) based on genetic stocks, geographic distribution, and migration patterns. RMUs delineate sea turtle assemblages below the species level but above the population level or breeding rookery. Within RMUs, sea turtles share demographic trajectories arising from similar biological and anthropogenic environmental factors (Wallace et al. 2010a , 2023 ). By integrating biogeographical information across life stages, RMUs provide a suitable framework for comparing several aspects of sea turtle populations, including natural history features, threats, and conservation status across the species global range (e.g. Fuentes et al. 2013 ; Wallace et al. 2010b , 2020 ; Esteban et al. 2020 ; Robinson and Pfaller 2022 ). In this study, we explore the parasite diversity of two sea turtles species relatively underrepresented in parasite studies: the loggerhead ( Caretta caretta ) and leatherback ( Dermochelys coriacea ) turtles. Our focus is in the South West Atlantic (SWA) region (Fig. 1 a), where the few existing parasite records are limited to tropical and subtropical areas (e.g. Werneck and Silva 2016 ), leaving a knowledge gap in southern temperate latitudes (> 34ºS). In fact, only one record of a parasite has been reported in this region more than 40 years ago (Boero and Led 1974 ). Specifically, we aim to: 1) identified the parasites present in loggerhead and leatherback turtles in the temperate SWA through morphological and molecular tools, and 2) to compare parasite diversity of both turtle species with that described in the rest of their global distribution using the RMUs framework. We discuss the implications of our findings for current knowledge on the connectivity between RMUs, feeding ecology of the species, and health status of populations. Additionally, we identify gaps and outline next steps in parasite studies on sea turtles. Materials and methods Study area and specimen collection Dead sea turtles were collected between December and May during the period 2008–2023 along more than 1,000 km of coastline of northern Argentina (Fig. 1 a). Specimens were found stranded at beaches or recovered from bycatch in artisanal gillnets. Standard curved carapace length (SCL) was measured according to Bolten ( 2000 ) and ontogenetic stage was determined following the minimum size at the nearest nesting sites in the SWA, i.e., 83 cm for loggerheads and 139 cm for leatherbacks (Baptistotte et al. 2003 ; Thomé et al. 2007 ). Necropsy was performed on recently dead to moderately decomposed turtles following Work ( 2000 ). The digestive tract was extracted and separated into esophagus, stomach and intestine. Each section was opened longitudinally and the content was collected using water and a container. The contents were then filtered through two sieves, a large one of 10 mm mesh and a smaller one of 300 µm. Other viscera such as lung, liver, heart and kidney were also examined for parasites. The filtrate and the organs were separated into capsules to be examined under a stereoscopic microscope. Parasites found were preserved in ethanol 70% for their morphological identification. Some specimens were isolated in Eppendorf tubes and frozen at -20⁰C for genetic analysis. Morphological and genetic study of parasites For morphological identification of nematodes and hirudineans were temporarily mounted and cleared in Amman’s Lactophenol, and trematodes were stained with hydrochloric carmine, dehydrated in a graded ethanol series, cleared in eugenol, and permanently mounted in natural Canada balsam for their study using a polarizing microscope (Olympus BX51®, Tokyo, Japan). Additionally, photographs were taken with a Q-Imaging Go-3 digital camera. Specimens were identified according to Looss ( 1899 ), Werneck et al. ( 2012 ), and Greiner ( 2013 ). Prevalence (P), abundance (A) and mean intensity (MI) were calculated for each parasite species (Bush et al. 1997 ). Specimens were deposited in the Helminthological Collection of Museo de La Plata (La Plata, Buenos Aires province, Argentina- number requested). For genetic characterization DNA was extracted from isolates using 200 µl of 5% Chelex solution (Bio-Rad Laboratories, CA, USA), 0.2 mg/ml Proteinase K (Roche) and incubated overnight at 56⁰C followed by 10 min at 95⁰C. Nuclear 18S, 28S, and ITS2 rDNA amplification were done using the appropriate primers (Littlewood, 1994 ; Cribb et al., 1998 , Floyd et al., 2005 ). Each 50 µl PCR contained 25 µl of GoTaq Green Master Mix (Promega, Madison, Wi, USA) 2.5 µl of each primer, 17 µl of water, and 3 µl of extracted DNA. PCR amplification for 18S was performed using an Eppendorf Mastercycler ep gradient S, consisting of 94°C for 15 min, followed by 35 cycles of 94°C for 30 s, 60°C for 30 s, and 72°C for 70 s, with a final extension of 72°C for 240 s, for 28S amplification the program consisting of 94 ⁰C 4 min, followed by 30 cycles of 95 ⁰C for 60 s, 60 ⁰C for 60 s, and 72 ⁰C for 120 s, with a final extension of 72 ⁰C for 4 min, and for ITS2 amplification was one cycle of 95°C 3 min, 42°C 2 min and 72°C 1 min, followed by 6 cycles of 95°C 45 s, 47°C 45 s and 72°C 1 min, followed with 35 cycles of 95°C 20 s, 50°C 20 s and 72°C 1 min, and a final extension of 72°C for 5 min. PCR products were purified and sequenced by Macrogen, South Korea. Sequences were edited and aligned using Chromas® version 2.6.6 and GAP® version 4.11.2 (Bonfield et al. 1995 ) and then compared with the NCBI database using BLAST version 2.2.26 (Altschul et al. 1997 ) to find sequences similar to those obtained. Biogeographic analysis To compare the parasite diversity of turtles from the temperate SWA with previous records in the rest of the region and the species global distribution we conducted a literature search by means of Google Scholar and PubMed. We searched the keywords "sea turtles", " Dermochelys coriacea ", "leatherback", " Caretta caretta ", "loggerhead", "parasites", "Nematoda", "Digenea", “Cestoda” and “ Ozobranchus ”. For each report found, we recorded the location and the parasite species, along with any information on its prevalence, intensity and abundance when available. The records found were then assigned to the 10 and seven RMUs defined by Wallace et al. ( 2023 ) for loggerheads and leatherbacks, respectively. Results Turtle morphometrics Loggerhead SCL ranged from 60.0 to 115.0 cm (mean = 70.9 ± 13.2 cm, n = 21), corresponding to juvenile and adult individuals. Leatherback SCL ranged from 133.0 to 155.0 cm (mean = 146.3 ± 8.6 cm, n = 6), corresponding to sub-adult and adult individuals. New records of parasites in the temperate SWA A total of 4505 parasite individuals were recovered and identified in 24 loggerhead (P = 83.3; A = 4407; MI = 1695) and six leatherback turtles (P = 83; A = 98; MI = 19.6). In loggerheads, parasite species found were Orchidasma amphiorchis (P = 33; A = 829; IM = 112.6), Pleurogonius longiusculus (P = 4; A = 1; IM = 1), Pyelosomum renicapite (P = 37; A = 557; IM = 61.8), Kathlania leptura (P = 20; A = 296; IM = 59), Sulcascaris sulcata (P = 79; A = 2277; IM = 119.8) and Ozobranchus margoi (P = 4; A = 447; IM = 447); while in leatherbacks only O. amphiorchis (P = 50; A = 15; IM = 5) and P. renicapite (P = 33; A = 83; IM = 41.5) were recorded (Fig. 1 b). All parasites were found in the digestive tract, no individuals were found in the rest of the viscera. The 18S gene sequence was obtained for the nematodes K. leptura and S. sulcata (GenBank acc. Num: XXXXX, GenBank acc. Num: XXXXX, respectively). While the sequence of K. leptura was the first molecular contribution, the sequence of S. sulcata aligned (99% similarity) with those previously recorded in GenBank and thus confirmed the morphological identification (Fig. 2 ). In addition, the 28S gene sequence for the digenean O. amphiorchis (GenBank acc. Num: XXXXXX), and the ITS2 gene sequence for the digenean P. renicapite (GenBank acc. Num: XXXXXX) from loggerheads, were obtained. Both records did not match any sequences in GenBank because there are no previous sequences available for these species. Distribution of sea turtle parasites We found 67 scientific papers reporting 58 parasite species for loggerheads and seven species for the leatherbacks worldwide (Figs. 3 , 4 , Tables 1, 2 ). Of the 10 loggerhead RMUs, the Northwest Atlantic (NWA) had the most parasite records (n = 34), followed by the Mediterranean (MED, n = 30), SWA (n = 17, of which five are new contributions resulting from the present work), and Southeast Indian (SEI, n = 12). The remaining RMUs had less than ten parasite records (Fig. 3 ; Table 1). Table 2 Parasite species reported for Dermochelys coriacea by Regional Management Unit (RMU) defined by Wallace et al. ( 2023 ). Species RMU Reference Digenea Calycodes anthos Northwest Atlantic Threlfall 1979 ; Innis et al. 2010 Southwest Atlantic Werneck et al. 2012 Cymatocarpus sp. Northwest Atlantic Threlfall 1979 Enodiotrema carettae Manfredi et al. 1996 Enodiotrema instar Enodiotrema sp. Innis et al. 2010 Pyelosomum renicapite Northeast Indian Mohan 1970 Northwest Atlantic MacCallum 1921 ; Threlfall 1979 ; Almor et al. 1989 ; Dyer et al. 1995 ; Manfredi et al. 1996 ; Innis et al. 2010 ; Poppi et al. 2012 Southwest Atlantic Werneck et al. 2012 ; Present study Orchiodasma amphiorchis Southwest Atlantic Present study For leatherbacks, only three of the seven RMUs recorded parasites, with the NWA having the highest number of records (n = 6), followed by the SWA (n = 3, of which one is a new contribution from this work) and the Northeast Indian (NEI, n = 1) (Fig. 4 ; Table 2 ). Gaps of parasite records were identified in the Northwest and Southwest Indian for loggerheads; and in the Southwest Indian, and East and West Pacific RMUs for leatherbacks. Loggerheads from the SWA shared parasite species with several other RMUs: 13 species with the NWA, 11 with the MED, 5 with the SEI and one with the NEI. However, two parasite species were exclusive found in the SWA: Monticellius indicum , and P. elongatus (Table 1). Of the parasites identified in this study, P. longiusculus was also documented in the NWA and NEI, O. margoi in the NWA and MED, O. amphiorchis , K. leptura and S. sulcata in the NWA, MED and SEI, and P. renicapite was recorded in the NWA and at the confluence of the NWA, MED and NEA. Similarly, leatherbacks from the SWA shared parasite species with the MED, NWA and NEI. Only O. amphiorchis was exclusive of the SWA. Discussion In this study we provide new records of parasites for the loggerhead and leatherback turtles in the temperate SW Atlantic, region and species understudied. Particularly in Argentina, present study gives to known the second record of O. amphiorchis since it was found in a loggerhead by Boero and Led ( 1974 ). Also, new geographic records for loggerhead’s parasites including the digeneans P. longiusculus and P. renicapite , the nematodes K. leptura and S. sulcata , and the leech O. margoi are provided. We report P. renicapite in a leatherback for the first time in Argentina, and the finding of O. amphiorchis represents a new host-parasite association. Genetic information for K. leptura , O. amphiorchis and P. renicapite are given for the first time. Comparing on a global scale, the SWA share some parasite species with other RMUs in the northern and east hemispheres, but also exhibit exclusive parasite species. Gaps in parasite studies occur mostly in the East Atlantic, East Pacific and the Indian Ocean. Parasite studies and the ecology of sea turtles Mapping parasite diversity throughout sea turtle global distribution raises questions about many aspects of turtle ecology. One of these aspects is sea turtle migration and connectivity among RMUs. According to general parasitological knowledge, the biogeographic distribution of a parasite reflects that of its host (Marcogliese and Price 1997 ) to the extent that parasites are used as population biomarkers in several marine species (e.g. Catalano et al. 2014 ). Does the biogeographic distribution of turtle parasites resemble the biogeographic distribution of their hosts? More precisely, can sea turtle parasites be used to better resolve current RMUs? Founding the answers to these questions is not straightforward. For example, loggerheads from the SWA share parasite species with those of the NWA, in accordance with the partial overlap defined by Wallace et al. ( 2023 ) based on genetic and migration information (Fig. 3 ). But SWA loggerheads also share parasite species with more distant ࣧnot overlappingࣧ RMUs, such as the MED, NEI and SEI (see Table 1). Given that most parasitic infection in sea turtles requires the occurrence of an intermediate host (Corner et al. 2022 ; Santoro et al. 2022 ), the shared parasite species among distant but non-overlapping RMUs likely arise from similar ecological conditions in regions. This similarity allows for the independent development of the parasite life cycle, rather than from undocumented connectivity (through turtle migration) between RMUs. At the same time, each loggerhead RMUs exhibit exclusive parasite species (e.g. M. indicum in the SWA, see Table S1 on Online Resource 1) that could act as biomarkers of turtles, especially in regions where RMUs overlap. For example, MED overlap with NWA and NEA (Fig. 3 ) particularly in the western Mediterranean. Cribb et al. ( 2017 ) distinguish between western and eastern Mediterranean turtles, highlighting that the former may bring their parasites from the NWA. Which is the origin of a loggerhead found in this region? If there was sufficient parasitological knowledge of turtles, this question could be answered relatively easy by examining common and exclusive parasite species (Fig. 5 ). Species such as Anisakis pegreffii and Styphlotrema solitaria have been recorded both in MED and at the overlap zone of the three mentioned RMUs but not in NWA, so a turtle harboring both parasite species might belong to MED rather than to the Atlantic. Inversely, species such as Rhadinorhynchus pristis has been documented only at the overlap zone of the three RMUs and not in the relatively well-studied MED and NWA, indicating that a loggerhead found in this region might belong to the NEA (where no parasite has been recorded yet). Similarly, parasites present in the overlap zone of the three RMUs and as well in MED and NWA, could be expected to be found in the unexplored NEA. Implementation of parasites as biomarkers of turtle origin requires an exhaustive sampling of turtle parasites throughout RMUs, to ensure that exclusive parasite species are not the product of insufficient number of hosts examined. Parasites can also be useful in studies of feeding ecology. Most marine helminth parasites have intermediate hosts that depend on trophic interactions for their transmission (Marcogliese 2004 , 2005 ), so the identification of a parasite species can be indicative of host diet, especially in regions where such information is scarce. In the SWA, nine studies list prey of loggerheads and leatherbacks (e.g. Frazier 1985 ; Carranza et al. 2010 ; DiBeneditto et al. 2015 ), but none of these prey were reported to be intermediate host for these turtles. Sulcascaris sulcata is the only sea turtle parasite for which the life cycle is known (Berry and Cannon 1981 ). This parasite has an indirect life cycle, with a bivalve or gastropod mollusc acting as intermediate host (Sprent 1977 ; Santoro et al. 2022 ). In this study, S. sulcata was recorded always associated with the presence of gastropods in the digestive tract of loggerheads (e.g. Rapana venosa , Pachycymbiola spp, Zidona spp.; Personal observation), but unfortunately its intermediate host could not be identified. Another aspect that can be informed by parasite studies is the ontogenetic shift undergone by sea turtles within RMUs. In this study, the parasite prevalence in loggerhead was higher than that observed by Werneck et al. ( 2008 ) in Brazil (76% vs 41.7%). These authors recorded three digenean species ( Calycodes anthos , O. amphiorchis and P. renicapite ) and two nematode species ( K. leptura and S. sulcata ), with C. anthos as the dominant species. We recorded the same parasite species (except for C. anthos ), but S. sulcata was the dominant species. While differences in prevalence could be due to the origin of the hosts, the Argentine ones coming from strandings and the Brazilian ones coming from fishing by-catch (Werneck et al. 2008 ), also, differences in parasite communities among regions may obey to ecological reasons. For example, in the Mediterranean, differences in parasite communities among regions and turtles reflect the ontogenetic shift that loggerheads undergo from oceanic to neritic habitats (Santoro et al. 2010). Small pelagic juveniles exhibit a less diverse parasite community (only conformed by E. megachondrus and C. anthos ) compared to larger neritic juveniles, which parasite community includes several species of nematodes as well (Santoro et al. 2010a ). In the SWA, more information on the size of loggerheads included in parasite studies is needed to evaluate if differences in parasite communities are informative of turtle ecology. Loggerheads analyzed in this study were large neritic juveniles and adults, but unfortunately information on turtle size provided by Werneck et al. ( 2008 ) is incomplete, thus limiting the scope of any comparison. Lastly, parasite studies can be informative of the health status of turtle aggregations. We found a higher abundance of S. sulcata individuals (A = 2277) compared to that observed in other regions like Brazil (A = 33, Werneck et al. 2008 ) and Mediterranean (A = 196, Manfredi et al. 1998 ). Sulcascaris sulcata infection in loggerheads are known to be linked to ulcerative gastritis in the stomach mucosa. The severity of these lesions measured by the size of ulcers, correspond to the number of S. sulcata individuals (Santoro et al. 2019 ). In our study, we observed non-perforated ulcers (4 cm length) associated with S. sulcata in four out of the 24 turtles analysed. However, it is unlikely that parasitic infection contributes to the debilitation of the animals, since most of them exhibited good body condition, as evidenced by the presence of intracoelomic fat and recent food ingestion. On the other hand, the leech O. margoi found in this study is vector of the Chelonid Herpes Virus Type 5 (CHPHV-5) and other turtle-associated viruses (Rittenburg et al. 2021 ). Turtles infected with CHPHV-5 can develop fibropapillomatosis, characterized by the presence of internal and external benign tumors that, in severe cases, can lead to death due to wasting (Adnyana et al. 1997 ; Aguirre and Lutz 2004 ). While only one case of a green turtle with tumors was recently reported in Argentina (Origlia et al. 2023 ), fibropapillomatosis is frequent in the rest of the SWA (Silva-Junior et al. 2019). Considering the presence of O. margoi in loggerheads, virus infection could be expected even without the development of tumors (Gattamorta 2015 ). Therefore, studies to detect the virus in apparently uninfected turtles in Argentina would be necessary. Limitations of parasite studies in sea turtles and next steps Mapping parasite diversity throughout the RMUs of loggerheads and leatherbacks raises interesting question about host ecology, but also present some limitations. As noted by Poulin and Morand ( 2000 ), a key challenge in biogeographic studies of parasites is the risk that a map illustrating the distribution of species among regions merely reflects the variability in research activity among different parts of the world. In addition, from the non-studied RMUs, our estimation of parasite diversity in regions such as the Indian and the Pacific oceans is based on a few studies, examining less than five turtles. This suggests that several parasite species remain unrecorded due to an insufficient number of hosts examined. This is specially truth for leatherbacks, for which the limited parasite diversity observed can be attributed to the challenge of recovering and analysing hosts of considerable size (> 200 kg). Future parasite studies should prioritize understudied RMUs such as the NEA, the North and Southwest Indian, and the Pacific, for both loggerheads and leatherbacks. Additionally, comparisons of RMUs regarding the prevalence, intensity and abundances of parasites could not be performed in this study, given that these ecological parameters are rarely reported in both turtle species. Future parasite studies should also include these ecological data, along with precise information on the size of the turtles examined. Particularly in the SWA, next steps should include the identification of intermediate hosts of turtle parasites to a better understanding of the trophic relationships. This is especially important for preys like gelatinous plankton, which is difficult to identify due its rapid digestibility (Arai 2005 ; Doyle et al. 2007 ). Sea turtles and their digeneans parasites offer a unique opportunity to assess long-term feeding relationships. These parasites exhibit high host specificity in both their intermediate and definitive hosts, especially when the final host is a reptile (Chabaud and Bain 1994 ). Further studies are essential to actively search for latent viruses in turtles and their possible vectors, as well as other pathogenic agents. A comprehensive health diagnosis of populations is crucial to developing effective conservation plans. Conclusion The contribution of new records of sea turtle parasites, both geographically and in terms of new parasite-host associations, represent a significant step towards a better understanding of turtle ecology. However, to enhance the utility of parasite studies in understanding turtle ecology, it is crucial to gather more information on the parasites of current and probable preys of turtles. This will help advance our knowledge on the biodiversity and structure of food webs that support sea turtles. In this work, we show how knowledge of a parasite species ecology, such as S. sulcata , can provide us with valuable information about sea turtles, including diet, ontogenetic, and health status. Furthermore, integrating the systematics of parasites with the existing knowledge from RMUs can facilitate the development of tools for predicting the RMUs of the turtles found and the parasite species present in unstudied regions. However, our knowledge of the global parasite diversity of loggerhead and leatherback turtles is still incomplete, with parasite studies lacking in several regions. We encourage for genetic characterization of parasites to help future research on phylogenetic relationships. Declarations Author Contribution E.O.P and V.G.C conceived and designed research. E.O.P, V.G.C, K.C.A, S.R.H, A.R, M.V, I.M.B, J.P.L, L.D and A.F carried out fieldwork. E.O.P, V.G.C, M.R.W and J.I.D analyzed data and wrote the manuscript. All authors read and approved the manuscript. Acknowledgement This manuscript would not be possible without the collaboration of artisanal fishers from San Clemente del Tuyú, who provided sea turtle individuals found dead in fishing gear. We are also grateful to technicians and researchers from Fundación Mundo Marino and Parque Educativo Mundo Marino, Prefectura Naval Argentina, park rangers and lifeguards from Buenos Aires province, who assisted during fieldwork. We also thank the support given by the Mar del Plata Aquarium thorough Alejandro Saubidet. Funding was partially provided by the Subsidio del Fondo para la Investigación Científica y Tecnológica (FONCyT) to the project Nº 1575-2017 of VGC. This is INIDEP contribution no. XXXX. The authors have no relevant financial or nonfinancial interest to disclose. References Adnyana W, Ladds PW, Blair D (1997) Observations of fibropapillomatosis in green turtles ( Chelonia mydas ) in Indonesia. Australian Vet J 75:737–742. https://doi.org/10.1111/j.1751-0813.1997.tb12258.x Aguirre AA, Lutz PL (2004) Marine turtles as sentinels of ecosystem health: is fibropapillomatosis an indicator? EcoHealth 1:275–283. https://doi.org/10.1007/s10393-004-0097-3 Almor P, Raga JA, Abril E et al (1989) Parasitisme de la tortue luth, Dermochelys coriacea (Linnaeus, 1766) dans les eaux europeennes par Pyelosomum renicapite (Leidy, 1856). Vie et Milieu. Life & Environment 3:57–59 Altschul SF, Madden TL, Schäffer AA et al (1997) Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res 25:3389–3402. https://doi.org/10.1093/nar/25.17.3389 Arai MN (2005) Predation on pelagic coelenterates: a review. J Mar Biol Assoc United Kingdom 85:523–536. https://doi.org/10.1017/S0025315405011458 Araújo TL (1941) Nota sobre um trematoide Aspidogastridae de tartaruga marinha. Bol Ind Anim 4:3–4 Aznar FJ, Badillo FJ, Raga JA (1998) Gastrointestinal helminths of loggerhead turtles ( Caretta caretta ) from the western Mediterranean: constraints on community structure. J Parasitol 84:474–479. https://doi.org/10.2307/3284708 Baptistotte C, Thomé JCA, Bjorndal KA (2003) Reproductive Biology and Conservation Status of the Loggerhead Sea Turtle ( Caretta caretta ) in Espírito Santo State, Brazil. Chelonian Conserv Biol 4:1–7 Baylis HA (1928) XLI. — Records of some parasitic worms from British vertebrates. J Nat Hist 1:329–343 Berry GN, Cannon LRG (1981) The life history of Sulcascaris sulcata (Nematoda: Ascaridoidea), a parasite of marine molluscs and turtles. Int J Parasitol 11:43–54 Blair D (1984) Elytrophallus carettae sp. n. (Digenea: Hemiuridae) from the stomach of loggerhead turtles ( Caretta caretta (L.)) from Australia. P Helm Soc Washington 51:135–139 Blair D, Limpus CJ (1982) Some digeneans (Platyhelminthes) parasitic in the Loggerhead Turtle, Caretta caretta (L). in Australia. Aust J Zool 30:653–680 Boero JJ, Led JE (1974) Parasites of the autochthonous fauna. Rev Agron Veter 3:16–17 Bolten AB (2000) Técnicas para la medición de tortugas marinas. In: Eckert KL, Bjorndal KA, Abreu-Grobois FA, Donnelly M (eds) Técnicas de investigación y manejo para la conservación de las tortugas marinas, Grupo especialista en tortugas marinas IUCN/CSE, Publicación no. 4, pp 110–114 Bolten AB (2003) Variation in sea turtle life history patterns: neritic vs. oceanic developmental stages. In: Lutz PL, Musick JA, Wyneken J (eds) The biology of sea turtles, Vol 2, 1st edn. CRC Press, Boca Raton, pp 243–257 Bonfield JK, Smith KF, Staden R (1995) A new DNA sequence assembly program. Nucleic Acids Res 24:4992–4999 Bursey CR, Manire CA (2006) Angiostoma carettae n. sp. (Nematoda: Angiostomatidae) from the loggerhead sea turtle Caretta caretta (Testudines: Cheloniidae), Florida, USA. Comp Parasitol, 73:253–256. https://doi.org/10.1654/4200.1 Bursey CR, Richardson KE, Richardson DJ (2006) First North American records of Kathlania leptura and Tonaudia tonaudia (Nematoda: Kathlanidae), parasites of marine turtles. Comp Parasitol 73:134–135. https://doi.org/10.1654/0002.1 Bush AO, Lafferty KD, Lotz JM et al (1997) Parasitology meets ecology on its own terms: Margolis et al. Revisited. J Parasitol 83:575–583. https://doi.org/10.2307/3284227 Carranza A, Estrades A, Scarabino F, Segura A (2010) Loggerhead turtles Caretta caretta (Linnaeus) preying on the invading gastropod Rapana venosa (Valenciennes) in the Río de la Plata Estuary. Mar Ecol 32:142–147. https://doi.org/10.1111/j.1439-0485.2010.00424.x Cary LR (1930) Report on Investigations at Tortugas. Studies on Miracidia. Carnegie Inst Washington 29:325–329 Catalano SR, Whittington ID, Donnellan SC, Gillanders BM (2014) Parasites as biological tags to assess host population structure: guidelines, recent genetic advances and comments on a holistic approach. Int J Parasitol: Parasites and Wildlife, 3:220–226. https://doi.org/10.1016/j.ijppaw.2013.11.001 Cavaco B, De Carvalho LM, Werneck MR (2021) Some digenetic trematodes found in a loggerhead sea turtle ( Caretta caretta ) from Brazil. Helminthologia 58:217–224. https://doi.org/10.2478/helm-2021-0023 Chabaud AG, Bain O (1994) The evolutionary expansion of the Spirurida. Int J Parasitol 24:1179–1201. https://doi.org/10.1016/0020-7519(94)90190-2 Chattopadhyaya DR (1972) Studies on the trematode parasites of reptiles found in India. Contribution to our knowledge of the family Pronocephalidae Looss, 1902. Riv Parassitol 33: 99–124 Corner RD, Cribb TH, Cutmore SC (2022) Vermetid gastropods as key intermediate hosts for a lineage of marine turtle blood flukes (Digenea: Spirorchiidae), with evidence of transmission at a turtle rookery. Int J Parasitol 52:225–241. https://doi.org/10.1016/j.ijpara.2021.08.008 Cribb TH, Adlard RD, Bray RA (1998) A DNA-based demonstration of a three-host life-cycle for the Bivesiculidae (Platyhelminthes: Digenea). Int J Parasitol 28:1791–1795. https://doi.org/10.1016/S0020-7519(98)00127-1 Cribb TH, Crespo-Picazo JL, Cutmore SC, Stacy BA, Chapman PA, García-Párraga D (2017) Elucidation of the first definitively identified life cycle for a marine turtle blood fluke (Trematoda: Spirorchiidae) enables informed control. Int J Parasitol 47:61–67. https://doi.org/10.1016/j.ijpara.2016.11.002 Davies RW, Chapman CG (1974) First record from North America of the piscicolid leech, Ozobranchus margoi , a parasite of marine turtles. J Fish Boar Canada 31:104–106. https://doi.org/10.1139/f74-016 Di Beneditto APM, De Moura JF, Siciliano S (2015) Feeding habits of the sea turtles Caretta caretta and Lepidochelys olivacea in south-eastern Brazil. Mar Biodiver Rec 8: e122 Di Renzo L, Di Gialleonardo L, Marchiori E et al (2021) Cucullanus carettae Baylis, 1923, in a loggerhead sea turtle ( Caretta caretta ) from the Adriatic sea: first detection and molecular characterization. Parasitol Res 120:341–345. https://doi.org/10.1007/s00436-020-06936-5 Doyle TK, Houghton JD, Buckley SM, Hays GC, Davenport J (2007) The broad-scale distribution of five jellyfish species across a temperate coastal environment. Hydrobiologia 579: 29–39. https://doi.org/10.1007/s10750-006-0362-2 Dyer WG, Williams EH, Bunkley-Williams L et al (1995) Some digeneans (Trematoda) at the Atlantic Hawksbill turtle, Eretmochelys imbricata imbricata (Testudines: Cheloniidae) from Puerto Rico. J Helminthol Soc Wash 62:13–17 Ernst CH, Ernst EM (1977) Ectoparasites associated with neotropical turtles of the genus Callopsis (Testudines, Emydidae, Batagurinae). Biotropica 9:139–142. https://doi.org/10.2307/2387671 Esteban N, Mortimer JA, Stokes HJ, Laloë JO, Unsworth RK, Hays GC (2020) A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels. Mar Biol 167:1–17. https://doi.org/10.1007/s00227-020-03786-8 Euzet L, Combes C, Triquell A (1972) On two trematodes from Caretta caretta (L.) from the French Mediterranean coast. Vie et Milieu, A (Biologie Marine) 23:157–167 Floyd RM, Rogers AD, Lambshead PJD, Smith CR (2005) Nematode-specific PCR primers for the 18S small subunit rRNA gene. Mol Ecol Notes 5:611–612. https://doi.org/10.1111/j.1471-8286.2005.01009.x Frazier J (1985) Misidentifications of sea turtles in the East Pacific: Caretta caretta and Lepidochelys olivacea . J Herpetol 19:1–11. Fuentes MM, Pike DA, Dimatteo A, Wallace BP (2013) Resilience of marine turtle regional management units to climate change. Glob Change Biol 19:1399–1406. https://doi.org/10.1111/gcb.12138 Gagne RB, Crooks KR, Craft ME, Chiu ES et al (2022) Parasites as conservation tools. Conserv Biol 36: e13719. https://doi.org/10.1111/cobi.13719 Gattamorta MA (2015) Ecología, prevalencia e caracterizacao molecular de Chelonid fibropapilloma-associated herpesvirus (CFPHV) em tartarugas verdes ( Chelonia mydas ) em áreas da costa brasileira (Thesis). Piracicaba, Brazil. Gentile A, Amato T, Gustinelli A, Fioravanti ML et al (2021) Helminth Infection of the Loggerhead Sea Turtle Caretta caretta along the Coasts of Sicily and the North West Adriatic Sea. Animals 11:1408. https://doi.org/10.3390/ani11051408 Gračan R, Mladineo I, Kučinić M, Lazar B, Lacković G (2012) Gastrointestinal helminth community of loggerhead sea turtle Caretta caretta in the Adriatic Sea. Dis Aquat Org 99:227–236. https://doi.org/10.3354/dao02490 Greiner EC (2013) Parasites of marine turtles. In: Wyneken J, Lohmann KJ, Musick JA (eds) The biology of sea turtles, Vol 3, 1 st edn. CRC Press, Boca Raton, pp 425–444 Hamann M, Godfrey MH, Seminoff JA et al (2010). Global research priorities for sea turtles: informing management and conservation in the 21st century. Endanger Species Res 11: 245–269. https://doi.org/10.3354/esr00279 Inglis WG (1957) A revision of the nematode genera Kathlania and Tonaudia . Ann Magaz Nat Hist 10:785–800 Innis C, Merigo C, Dodge K et al (2010) Health evaluation of leatherback turtles ( Dermochelys coriacea ) in the northwestern Atlantic during direct capture and fisheries gear disentanglement. Chelonian Conserv Biol 9:205–222 Jacobson ER, Homer BL, Stacy BA et al (2006) Neurological disease in wild loggerhead sea turtles Caretta caretta . Dis Aquat Org 70:139–154. https://doi.org/10.3354/dao070139 Karaa S, Jribi I, Marouani S et al (2019) Preliminary study on parasites in loggerhead turtles ( Caretta caretta ) from the Southern Tunisian waters. Am J Biomed Sci & Res 5:373–376 Kawazu I, Ueda K, Hirai S, Maeda K, Yanagisawa M, Miyaraha H (2018) Captive Loggerhead Turtle Hatchlings Infected by Parasitic Cardiovascular Blood Flukes. Mar Turt Newslet 155:20–21 Lent H, Teixeira de Freitas JF (1948) Uma coleção de nematódeos, parasitos de vertebrados do Museu de História natural de Montevidéu. Mem Inst Oswaldo Cruz 46:1–71 Lester RJG, Blair D, Heald D (1980) Nematodes from scallops and turtles from Shark Bay, Western Australia. Aust J Mar Freshwater Res 31:713–717 Linton E (1910) Helminth fauna of the Dry Tortugas. 11. Trematodes. Pap Tortugas Lab 4:11–98 Littlewood DTJ (1994) Molecular phylogenetics of cupped oysters based on partial 28S rRNA gene sequences. Mol Phylogenet Evol 3:221–229. https://doi.org/10.1006/mpev.1994.1024 Looss A (1899) Weitere Beiträge zur Kenntniss der Trematoden-Fauna Aegyptens, zugleich Versuch einer natürlichen Gliederung des Genus Distomum Retzius. Zoologische Jahrbücher 12:521–784 Luhman M (1935) Two new trematodes from the loggerhead turtle ( Caretta caretta ). The J Parasitol 21:274–276. https://doi.org/10.2307/3271358 MacCallum GA (1921) Studies in helminthology. Zoopathologica 1:137–284 Manfredi MT, Piccolo G, Prato F, Loria GR (1996) Parasites in Italian sea turtles. I. The leatherback turtle Dermochelys coriacea (Linnaeus, 1766). Parassitologia 38:581–583 Manfredi MT, Piccolo G, Meotti C (1998) Parasites of Italian sea turtles. II. Loggerhead turtles ( Caretta caretta [Linnaeus, 1758]). Parassitologia 40:305–308. Manire CA, Kinsel MJ, Anderson ET, Clauss TM, Byrd L (2008) Lungworm infection in three loggerhead sea turtles, Caretta caretta . J Zoo Wildl Med 39:92–98. https://doi.org/10.1638/2007-0092.1 Manter HW (1932) Continued studies on Trematodes of Tortugas. Carnegie Inst Washington Year Book 31:287–288 Manter HW, Larson MI (1950) Two new blood flukes from a marine turtle, Caretta caretta . J Parasitol 36:595–599. https://doi.org/10.2307/3273293 Marangi M, Carlino P, Profico C et al (2020) First multicenter coprological survey on helminth parasite communities of free-living loggerhead sea turtles Caretta caretta (Linnaeus, 1758) from the Adriatic Sea and Northern Ionian Sea. Int J Parasitol: Parasites Wildlife 11:207–212. https://doi.org/10.1016/j.ijppaw.2020.02.006 Marcer F, Tosi F, Franzo G, Vetri A, Ravagnan S, Santoro M, Marchiori E (2020) Updates on ecology and life cycle of Sulcascaris sulcata (Nematoda: Anisakidae) in Mediterranean Grounds: Molecular Identification of larvae infecting edible scallops. Front Vet Sci 7:64. https://doi.org/10.3389/fvets.2020.00064 Marchiori E, Negrisolo E, Cassini R et al (2017) Cardiovascular flukes (Trematoda: Spirorchiidae) in Caretta caretta Linnaeus, 1758 from the mediterranean sea. Parasites Vectors 10:1–14. https://doi.org/10.1186/s13071-017-2396-x Marcogliese DJ (2004) Parasites: small players with crucial roles in the ecological theater. EcoHealth 1:151-164. https://doi.org/10.1007/s10393-004-0028-3 Marcogliese DJ (2005) Transmission of marine parasites. In: Rohde K (ed) Marine Parasitology, 1st edn. Csiro, New York, pp 280–286 Marcogliese DJ (2023) Major drivers of biodiversity loss and their impacts on helminth parasite populations and communities. J Helminthol 97: e34. https://doi.org/10.1017/S0022149X2300010X Marcogliese DJ, Price J (1997) The paradox of parasites. Global biodiversity 7:7–15 Monticelli FS (1896) Di un ematozoo della Thalassochelys caretta Linn. Internationale Monatsschrift fur Anatomie und Physiologie 13:141–172 Mohan RS (1971) Occurrence of the digenetic trematode Astrorchis renicapite (Leidy) family: Pronocephalidae) in the leathery turtle Dermochelys coriacea (Linne) from the Indian Ocean. Cent Mar Fisher Res Inst 6:489–490 Musick JA, Limpus CJ (1997) Habitat utilization and migration in juvenile sea turtles. In: Lutz PL, Musick JA (eds) The Biology of Sea Turtles, 1st edn. CRC Press, Boca Raton, pp 137–164 Origlia JA, Loureiro JP, Tizzano MA et al (2023) Fibropapillomatosis Associated with Chelonid alphaherpesvirus 5 (ChHV5) in a Green Turtle Chelonia mydas in Argentine Waters. J Wildl Dis 59:363–366. https://doi.org/10.7589/JWD-D-22-00083 Piccolo G, Manfredi MT (2001) New reports on parasites of marine turtles stranded along the Italian coasts. In: Margaritoulis D, Demetropoulos A (eds) First Mediterranean conference on marine turtles, 1 st edn. ICRAM, Roma, pp 207–211 Platt TR, Blair D (1998) Redescription of Hapalotrema mistroides (Monticelli, 1896) and Hapalotrema synorchis Luhman, 1935 (Digenea: Spirorchiidae), with comments on other species in the genus. J Parasitol 84:594–600. https://doi.org/10.2307/3284729 Poppi L, Zaccaroni A, Pasotto D et al (2012) Post-Mortem investigations on a leatherback turtle Dermochelys coriacea stranded along the Northern Adriatic coastline. Dis Aquat Org 100:71–76. https://doi.org/10.3354/dao02479 Poulin R, Morand S (2000) The diversity of parasites. Q Rev Biol 75:277–293 Pratt HS (1914) Trematodes of the loggerhead turtle (Caretta caretta) of the Gulf of Mexico. Arch Parasitol 41:1–27 Rittenburg LT, Kelley JR, Mansfield KL, Savage AE (2021) Marine leech parasitism of sea turtles varies across host species, seasons, and the tumor disease fibropapillomatosis. Dis Aquat Org 143:1–12. https://doi.org/10.3354/dao03549 Robinson NJ, Pfaller JB (2022) Sea turtle epibiosis: Global patterns and knowledge gaps. Front Ecol Evol 10: 844021. https://doi.org/10.3389/fevo.2022.844021 Rodenbusch CR, Marks FS, Canal CW, Reck J (2012) Marine leech Ozobranchus margoi parasitizing loggerhead turtle ( Caretta caretta ) in Rio Grande do Sul, Brazil. Rev Brasileira Parasitol Vet 21:301–303. Santoro M, Badillo FJ, Mattiucci S et al (2010a) Helminth communities of loggerhead turtles ( Caretta caretta ) from Central and Western Mediterranean Sea: The importance of host's ontogeny. Parasitol Int 59:367–375. https://doi.org/10.1016/j.parint.2010.04.009 Santoro M, Mattiucci S, Paoletti M et al (2010b). Molecular identification and pathology of Anisakis pegreffii (Nematoda: Anisakidae) infection in the Mediterranean loggerhead sea turtle ( Caretta caretta ). Vet Parasitol 174:65–71. https://doi.org/10.1016/j.vetpar.2010.08.018 Santoro M, Di Nocera F, Iaccarino D et al (2017) Pathology and molecular analysis of Hapalotrema mistroides (Digenea: Spirorchiidae) infecting a Mediterranean loggerhead turtle Caretta caretta . Dis Aquat Org 124:101–108. https://doi.org/10.3354/dao03117 Santoro M, Marchiori E, Iaccarino D et al (2019) Epidemiology of Sulcascaris sulcata (Nematoda: Anisakidae) ulcerous gastritis in the Mediterranean loggerhead sea turtle ( Caretta caretta ). Parasitol Res 118:1457–1463. https://doi.org/10.1007/s00436-019-06283-0 Santoro M, Marchiori E, Cassini R et al (2020) Epidemiology of blood flukes (Digenea: Spirorchiidae) in sea turtles from Tyrrhenian and Adriatic Seas, off Italy. Parasites Vectors 13:1–10. https://doi.org/10.1186/s13071-020-3922-9 Santoro M, Palomba M, Modica MV (2022) Larvae of Sulcascaris sulcata (Nematoda: Anisakidae), a parasite of sea turtles, infect the edible purple dye murex Bolinus brandaris in the Tyrrhenian Sea. Food Control 132:108547. https://doi.org/10.1016/j.foodcont.2021.108547 Sey O (1977) Examination of helmints parasites of marine turtles caught along the Egyptian coast. Acta Zoologica Academiae Scientiarium Hungaricae 23:3–4 Silva-Júnior ESD, de Farias DSD, Costa Bomfim AD et al (2019) Stranded marine turtles in northeastern Brazil: incidence and spatial–temporal distribution of fibropapillomatosis. Chel Conserv Biol 18:249–258. https://doi.org/10.2744/CCB-1359.1 Simha SS (1977) On a new genus and species of a blood-fluke Neocaballerotrema caballeroi , from a marine turtle in India. Universidad Nacional Autonoma de Mexico, Instituto de Biología, Mexico, pp 307–310 Simha SS, Chattopadhyaya DR (1978) Studies on the trematode parasites of reptiles found in India. Contribution to the knowledge of blood flukes from the marine turtles, from the Gulf of Manar, South India. J Zool Soc India 30:69–82 Sprent JFA (1977) Ascaridoid nematodes of amphibians and reptiles: Sulcascaris . J Helminthol 51:379–387. https://doi.org/10.1017/S0022149X00007744 Stacy BA, Foley AM, Greiner E et al (2010) Spirorchiidiasis in stranded loggerhead Caretta caretta and green turtles Chelonia mydas in Florida (USA): host pathology and significance. Dis Aquat Org 89:237–259. https://doi.org/10.3354/dao02195 Sterioti A, Doxa CC, Grigoriou P, Vardanis G, Cascarano MC, Katharios P (2017) Ozobranchus margoi infections in loggerhead turtles ( Caretta caretta ) in Greece and potential treatment options. J Exot Pet Med 26:196–199. https://doi.org/10.1053/j.jepm.2017.05.006 Thomé JC, Baptistotte C, Moreira LMP, Scalfoni JT, Almeida AP, Rieth DB, Barata PC (2007) Nesting biology and conservation of the leatherback sea turtle ( Dermochelys coriacea ) in the state of Espírito Santo, Brazil. Chelonian Conserv Biol 6:15–27 Threlfall W (1979) Three species of Digenea from the Atlantic leatherback turtle ( Dermochelys coriacea ). Canadian J Zool 57:1825–1829 Travassos L, Freitas T, Kohn A (1969) Trematódeos do Brasil. Mem Inst Oswaldo Cruz 67:1–886 Valente AL, Delgado C, Moreira C et al (2009) Helminth component community of the loggerhead sea turtle, Caretta caretta , from Madeira Archipelago, Portugal. J Parasitol 95:249–252. https://doi.org/10.1645/GE-1519.1 Viana L (1924) Tentativa de catalogação das especies brazileiras de trematódeos. Mem Inst Oswaldo Cruz 17:95–227 Wallace BP, DiMatteo AD, Hurley BJ et al (2010a) Regional management units for marine turtles: a novel framework for prioritizing conservation and research across multiple scales. Plos one 5: e15465. https://doi.org/10.1371/journal.pone.0015465 Wallace BP, Lewison RL, McDonald SL et al (2010b) Global patterns of marine turtle bycatch. Conserv Lett 3:131–142. https://doi.org/10.1111/j.1755-263X.2010.00105.x Wallace BP, Stacy BA, Cuevas E et al (2020) Oil spills and sea turtles: documented effects and considerations for response and assessment efforts. Endang Species Res 41:17–37. https://doi.org/10.3354/esr01009 Wallace BP, Posnik ZA, Hurley BJ et al (2023) Marine turtle regional management units 2.0: an updated framework for conservation and research of wide-ranging megafauna species. Endanger Species Res 52: 209–223. https://doi.org/10.3354/esr01243 Werneck MR, Thomazini CM, Mori ES, Gonçalves VT, GOMES BM (2008) Gastrointestinal helminth parasites of loggerhead turtle Caretta caretta Linnaeus 1758 (Testudines, Cheloniidae) in Brazil. Pan-American J Aquatic Science 3:351–354 Werneck MR, Verissimo L, Baldassin P et al (2012) Digenetic trematodes of Dermochelys coriacea from the Southwestern Atlantic Ocean. Mar Turtle News 132: 13 Werneck MR, Da Silva RJ (2016) Checklist of sea turtles endohelminth in Neotropical region. Helminthologia 53:211–223. https://doi.org/10.1515/helmin-2016-0045 Werneck MR, Hayes PM, Lawton SP (2019). Molecular evidence for resurrection of Plesiochorus elongatus (Digenea: Gorgoderidae): An urinary bladder parasite of sea turtles. Parasitol Inter 71:180–185 Werneck MR, Nunes C, Jerdy H, Carvalho ECQ (2017) Loggerhead turtle, Caretta caretta (Linnaeus, 1758) (Testudines, Cheloniidae), as a new host of Monticellius indicum Mehra, 1939 (Digenea: Spirorchiidae) and associated lesiond to spirorchiid eggs. Helminthologia 54:363–368. https://doi.org/10.1515/helm-2017-0047 Werneck MR, Mastrangelli A, Velloso R, Jerdy H, Carvalho EC (2018) Chronic cystitis associated with Plesiochorus cymbiformis (Rudolphi, 1819) Looss, 1901 (Digenea: Gorgoderidae) in a loggerhead turtle Caretta caretta (Linnaeus 1758) (Testudines, Cheloniidae) from Brazil: a case report. J Parasitol 104:334–336. https://doi.org/10.1645/17-116 Werneck, MR, Baldassin P, Mastrangelli A et al (2019). The First Occurrence of Enodiotrema megachondrus in a Loggerhead Turtle Found on the Coast of Brazil. EC Vet Sci 4:148–152 Work TM (2000) Manual de necropsia de tortugas marinas para biólogos en refugios o áreas remotas. US Geological Survey, National Wildlife Health Center, Hawaii Field Station, Honolulu, Hawaii Table 1 Table 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files OnlineresourceTableS1.xlsx Table 1S Parasite species reported for Caretta caretta by RMU. Table1.xlsx Table 1. Parasite species reported for Caretta caretta by Regional Management Unit (RMU) defined by Wallace et al. (2023). (External file) Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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1","display":"","copyAsset":false,"role":"figure","size":1734249,"visible":true,"origin":"","legend":"\u003cp\u003ea) Locations were specimens of \u003cem\u003eCaretta caretta\u003c/em\u003e and \u003cem\u003eDermochelys coriacea\u003c/em\u003ewere recovered for parasitological analysis. b) Parasite species found in in both sea turtle species\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/ccf603849a57dca510b76f37.jpg"},{"id":59906092,"identity":"835c0b36-66b1-4919-92a6-5d376e3dff82","added_by":"auto","created_at":"2024-07-09 06:55:39","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":279065,"visible":true,"origin":"","legend":"\u003cp\u003ePhylogenetic tree based on \u003cem\u003eS. sulcata\u003c/em\u003e 18S rDNA sequences newly obtained in this study with Anisakidae sequences available in GenBank using Maximum Likelihood method with a distance matrix calculation with K2P. An Ascaridoidea species were used as outgroup. The numbers at the nodes represent the percentages of 1000 bootstrap replicates. Sequences are identified by GenBank accession numbers and taxa names\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/64aa1f693ff69117d3719586.jpg"},{"id":59906685,"identity":"34ac2b72-ddcf-47c1-8c0c-256ea56aeb10","added_by":"auto","created_at":"2024-07-09 07:03:39","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2594940,"visible":true,"origin":"","legend":"\u003cp\u003eGlobal distribution of parasite records in \u003cem\u003eCaretta caretta\u003c/em\u003e organized according to Regional Management Units defined by Wallace et al. (2023). NEW: Northwest Atlantic, Southwest Atlantic, Northeast Atlantic, MED: Mediterranean, NWI: Northwest Indian, NEI: Northeast Indian, SWI: Southwest Indian, SEI: Southeast Indian, NP: North Pacific and SP: South Pacific\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/4dd055b25af4430016a5a9d9.jpg"},{"id":59904960,"identity":"d1c4ca0a-052d-4b92-a69d-a946a4c8383a","added_by":"auto","created_at":"2024-07-09 06:39:39","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2450203,"visible":true,"origin":"","legend":"\u003cp\u003eGlobal distribution of parasite records in \u003cem\u003eDermochelys coriacea\u003c/em\u003e organized according to Regional Management Units defined by Wallace et al. (2023). NWA: Northwest Atlantic, SWA: Southwest Atlantic, SEA: Southeast Atlantic, SWI: Southwest Indian, NEI: Northeast Indian, WP: West Pacific and EP: East Pacific\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/10e068d35062fbee66c2bac3.jpg"},{"id":59905589,"identity":"df4580e0-71b2-4175-bd67-4ffd34b1157c","added_by":"auto","created_at":"2024-07-09 06:47:39","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":929632,"visible":true,"origin":"","legend":"\u003cp\u003ea) Dichotomous diagram to establish the origin of loggerhead turtles according to their parasites, and b) table showing the shared or exclusive parasite species reported in a given Regional Management Unit or the overlap zone among them. MED: Mediterranean, NWA: Northwest Atlantic, NEA: Northeast Atlantic\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/dabcfc306b9d94c98bfc5993.jpg"},{"id":62532666,"identity":"6e8c3b16-bd3a-40f2-bd0f-43c9a9960cb1","added_by":"auto","created_at":"2024-08-15 12:58:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":8348839,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/9d595146-71e2-4315-920f-92ee80cc45b7.pdf"},{"id":59904956,"identity":"9594c7ca-a23a-4420-8892-8f7eb9fc6a2f","added_by":"auto","created_at":"2024-07-09 06:39:39","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":14297,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTable 1S \u003c/strong\u003eParasite species reported for \u003cem\u003eCaretta caretta\u003c/em\u003e by RMU.\u003c/p\u003e","description":"","filename":"OnlineresourceTableS1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/545fdd48b2fa129e8570294a.xlsx"},{"id":59904958,"identity":"4e62bc57-0e2c-4356-a758-3b4ff7e39e4d","added_by":"auto","created_at":"2024-07-09 06:39:39","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":16201,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTable 1. \u003c/strong\u003eParasite species reported for \u003cem\u003eCaretta caretta\u003c/em\u003e by Regional Management Unit (RMU) defined by Wallace et al. (2023). (External file)\u003c/p\u003e","description":"","filename":"Table1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-4600556/v1/9b20da438ff0ec618b6ac215.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Parasite diversity in sea turtles of the temperate SW Atlantic: a bridge between systematics and ecology","fulltext":[{"header":"Introduction","content":"\u003cp\u003eParasite studies can provide insights into major threats to global biodiversity, such as overexploitation, habitat fragmentation, and climate change among others (Gagne et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In aquatic environments, these studies offer valuable information on critical aspects of host ecology, including feeding habits, migrations, and exposure to environmental contaminants and stressors (Marcogliese \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2004\u003c/span\u003e, \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Given the role of parasites in regulating host population (Marcogliese and Price \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e1997\u003c/span\u003e), such studies are particularly important for species of conservation concern.\u003c/p\u003e \u003cp\u003eSea turtles are a group of seven species listed in categories from Data Deficient to Critically Endangered (IUCN 2023). For most species, the life cycle includes an ontogenetic shift from oceanic to neritic habitats, as well as a transition from omnivorous, pelagic feeding behavior to a more specialized, benthic feeding behavior (Musick and Limpus \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Bolten \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Even though most species connect ocean regions separated by thousands of kilometers, individuals often remain in certain feeding areas long enough to become infected with parasites (Greiner \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Sea turtle\u0026rsquo;s parasites have received considerable attention over time (e.g. Luhman \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e1935\u003c/span\u003e; Lester et al. \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e1980\u003c/span\u003e; Santoro et al. \u003cspan citationid=\"CR86\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), with greater focus on parasite systematics (Hamann et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) compared to ecological studies. While parasites are quite well known for certain turtle species and areas (e.g. the green turtle \u003cem\u003eChelonia mydas\u003c/em\u003e has the largest number of parasite records worldwide, much of which come from the Northwest Atlantic; Greiner \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), there are regions and species for which parasitological knowledge is still limited.\u003c/p\u003e \u003cp\u003eSea turtles are organized into Regional Management Units (RMUs) based on genetic stocks, geographic distribution, and migration patterns. RMUs delineate sea turtle assemblages below the species level but above the population level or breeding rookery. Within RMUs, sea turtles share demographic trajectories arising from similar biological and anthropogenic environmental factors (Wallace et al. \u003cspan citationid=\"CR100\" class=\"CitationRef\"\u003e2010a\u003c/span\u003e, \u003cspan citationid=\"CR103\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). By integrating biogeographical information across life stages, RMUs provide a suitable framework for comparing several aspects of sea turtle populations, including natural history features, threats, and conservation status across the species global range (e.g. Fuentes et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Wallace et al. \u003cspan citationid=\"CR101\" class=\"CitationRef\"\u003e2010b\u003c/span\u003e, \u003cspan citationid=\"CR102\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Esteban et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Robinson and Pfaller \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, we explore the parasite diversity of two sea turtles species relatively underrepresented in parasite studies: the loggerhead (\u003cem\u003eCaretta caretta\u003c/em\u003e) and leatherback (\u003cem\u003eDermochelys coriacea\u003c/em\u003e) turtles. Our focus is in the South West Atlantic (SWA) region (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea), where the few existing parasite records are limited to tropical and subtropical areas (e.g. Werneck and Silva \u003cspan citationid=\"CR106\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), leaving a knowledge gap in southern temperate latitudes (\u0026gt;\u0026thinsp;34\u0026ordm;S). In fact, only one record of a parasite has been reported in this region more than 40 years ago (Boero and Led \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1974\u003c/span\u003e). Specifically, we aim to: 1) identified the parasites present in loggerhead and leatherback turtles in the temperate SWA through morphological and molecular tools, and 2) to compare parasite diversity of both turtle species with that described in the rest of their global distribution using the RMUs framework. We discuss the implications of our findings for current knowledge on the connectivity between RMUs, feeding ecology of the species, and health status of populations. Additionally, we identify gaps and outline next steps in parasite studies on sea turtles.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy area and specimen collection\u003c/h2\u003e \u003cp\u003eDead sea turtles were collected between December and May during the period 2008\u0026ndash;2023 along more than 1,000 km of coastline of northern Argentina (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). Specimens were found stranded at beaches or recovered from bycatch in artisanal gillnets. Standard curved carapace length (SCL) was measured according to Bolten (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2000\u003c/span\u003e) and ontogenetic stage was determined following the minimum size at the nearest nesting sites in the SWA, i.e., 83 cm for loggerheads and 139 cm for leatherbacks (Baptistotte et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Thom\u0026eacute; et al. \u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Necropsy was performed on recently dead to moderately decomposed turtles following Work (\u003cspan citationid=\"CR111\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). The digestive tract was extracted and separated into esophagus, stomach and intestine. Each section was opened longitudinally and the content was collected using water and a container. The contents were then filtered through two sieves, a large one of 10 mm mesh and a smaller one of 300 \u0026micro;m. Other viscera such as lung, liver, heart and kidney were also examined for parasites. The filtrate and the organs were separated into capsules to be examined under a stereoscopic microscope. Parasites found were preserved in ethanol 70% for their morphological identification. Some specimens were isolated in Eppendorf tubes and frozen at -20⁰C for genetic analysis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eMorphological and genetic study of parasites\u003c/h2\u003e \u003cp\u003eFor morphological identification of nematodes and hirudineans were temporarily mounted and cleared in Amman\u0026rsquo;s Lactophenol, and trematodes were stained with hydrochloric carmine, dehydrated in a graded ethanol series, cleared in eugenol, and permanently mounted in natural Canada balsam for their study using a polarizing microscope (Olympus BX51\u0026reg;, Tokyo, Japan). Additionally, photographs were taken with a Q-Imaging Go-3 digital camera. Specimens were identified according to Looss (\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1899\u003c/span\u003e), Werneck et al. (\u003cspan citationid=\"CR105\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), and Greiner (\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Prevalence (P), abundance (A) and mean intensity (MI) were calculated for each parasite species (Bush et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e1997\u003c/span\u003e). Specimens were deposited in the Helminthological Collection of Museo de La Plata (La Plata, Buenos Aires province, Argentina- number requested).\u003c/p\u003e \u003cp\u003eFor genetic characterization DNA was extracted from isolates using 200 \u0026micro;l of 5% Chelex solution (Bio-Rad Laboratories, CA, USA), 0.2 mg/ml Proteinase K (Roche) and incubated overnight at 56⁰C followed by 10 min at 95⁰C. Nuclear 18S, 28S, and ITS2 rDNA amplification were done using the appropriate primers (Littlewood, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Cribb et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1998\u003c/span\u003e, Floyd et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Each 50 \u0026micro;l PCR contained 25 \u0026micro;l of GoTaq Green Master Mix (Promega, Madison, Wi, USA) 2.5 \u0026micro;l of each primer, 17 \u0026micro;l of water, and 3 \u0026micro;l of extracted DNA. PCR amplification for 18S was performed using an Eppendorf Mastercycler ep gradient S, consisting of 94\u0026deg;C for 15 min, followed by 35 cycles of 94\u0026deg;C for 30 s, 60\u0026deg;C for 30 s, and 72\u0026deg;C for 70 s, with a final extension of 72\u0026deg;C for 240 s, for 28S amplification the program consisting of 94 ⁰C 4 min, followed by 30 cycles of 95 ⁰C for 60 s, 60 ⁰C for 60 s, and 72 ⁰C for 120 s, with a final extension of 72 ⁰C for 4 min, and for ITS2 amplification was one cycle of 95\u0026deg;C 3 min, 42\u0026deg;C 2 min and 72\u0026deg;C 1 min, followed by 6 cycles of 95\u0026deg;C 45 s, 47\u0026deg;C 45 s and 72\u0026deg;C 1 min, followed with 35 cycles of 95\u0026deg;C 20 s, 50\u0026deg;C 20 s and 72\u0026deg;C 1 min, and a final extension of 72\u0026deg;C for 5 min.\u003c/p\u003e \u003cp\u003ePCR products were purified and sequenced by Macrogen, South Korea. Sequences were edited and aligned using Chromas\u0026reg; version 2.6.6 and GAP\u0026reg; version 4.11.2 (Bonfield et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e1995\u003c/span\u003e) and then compared with the NCBI database using BLAST version 2.2.26 (Altschul et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1997\u003c/span\u003e) to find sequences similar to those obtained.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eBiogeographic analysis\u003c/h2\u003e \u003cp\u003eTo compare the parasite diversity of turtles from the temperate SWA with previous records in the rest of the region and the species global distribution we conducted a literature search by means of Google Scholar and PubMed. We searched the keywords \"sea turtles\", \"\u003cem\u003eDermochelys coriacea\u003c/em\u003e\", \"leatherback\", \"\u003cem\u003eCaretta caretta\u003c/em\u003e\", \"loggerhead\", \"parasites\", \"Nematoda\", \"Digenea\", \u0026ldquo;Cestoda\u0026rdquo; and \u0026ldquo;\u003cem\u003eOzobranchus\u003c/em\u003e\u0026rdquo;. For each report found, we recorded the location and the parasite species, along with any information on its prevalence, intensity and abundance when available. The records found were then assigned to the 10 and seven RMUs defined by Wallace et al. (\u003cspan citationid=\"CR103\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) for loggerheads and leatherbacks, respectively.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eTurtle morphometrics\u003c/h2\u003e \u003cp\u003eLoggerhead SCL ranged from 60.0 to 115.0 cm (mean\u0026thinsp;=\u0026thinsp;70.9\u0026thinsp;\u0026plusmn;\u0026thinsp;13.2 cm, n\u0026thinsp;=\u0026thinsp;21), corresponding to juvenile and adult individuals. Leatherback SCL ranged from 133.0 to 155.0 cm (mean\u0026thinsp;=\u0026thinsp;146.3\u0026thinsp;\u0026plusmn;\u0026thinsp;8.6 cm, n\u0026thinsp;=\u0026thinsp;6), corresponding to sub-adult and adult individuals.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eNew records of parasites in the temperate SWA\u003c/h2\u003e \u003cp\u003eA total of 4505 parasite individuals were recovered and identified in 24 loggerhead (P\u0026thinsp;=\u0026thinsp;83.3; A\u0026thinsp;=\u0026thinsp;4407; MI\u0026thinsp;=\u0026thinsp;1695) and six leatherback turtles (P\u0026thinsp;=\u0026thinsp;83; A\u0026thinsp;=\u0026thinsp;98; MI\u0026thinsp;=\u0026thinsp;19.6). In loggerheads, parasite species found were \u003cem\u003eOrchidasma amphiorchis\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;33; A\u0026thinsp;=\u0026thinsp;829; IM\u0026thinsp;=\u0026thinsp;112.6), \u003cem\u003ePleurogonius longiusculus\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;4; A\u0026thinsp;=\u0026thinsp;1; IM\u0026thinsp;=\u0026thinsp;1), \u003cem\u003ePyelosomum renicapite\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;37; A\u0026thinsp;=\u0026thinsp;557; IM\u0026thinsp;=\u0026thinsp;61.8), \u003cem\u003eKathlania leptura\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;20; A\u0026thinsp;=\u0026thinsp;296; IM\u0026thinsp;=\u0026thinsp;59), \u003cem\u003eSulcascaris sulcata\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;79; A\u0026thinsp;=\u0026thinsp;2277; IM\u0026thinsp;=\u0026thinsp;119.8) and \u003cem\u003eOzobranchus margoi\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;4; A\u0026thinsp;=\u0026thinsp;447; IM\u0026thinsp;=\u0026thinsp;447); while in leatherbacks only \u003cem\u003eO. amphiorchis\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;50; A\u0026thinsp;=\u0026thinsp;15; IM\u0026thinsp;=\u0026thinsp;5) and \u003cem\u003eP. renicapite\u003c/em\u003e (P\u0026thinsp;=\u0026thinsp;33; A\u0026thinsp;=\u0026thinsp;83; IM\u0026thinsp;=\u0026thinsp;41.5) were recorded (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). All parasites were found in the digestive tract, no individuals were found in the rest of the viscera.\u003c/p\u003e \u003cp\u003eThe 18S gene sequence was obtained for the nematodes \u003cem\u003eK. leptura\u003c/em\u003e and \u003cem\u003eS. sulcata\u003c/em\u003e (GenBank acc. Num: XXXXX, GenBank acc. Num: XXXXX, respectively). While the sequence of \u003cem\u003eK. leptura\u003c/em\u003e was the first molecular contribution, the sequence of \u003cem\u003eS. sulcata\u003c/em\u003e aligned (99% similarity) with those previously recorded in GenBank and thus confirmed the morphological identification (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). In addition, the 28S gene sequence for the digenean \u003cem\u003eO. amphiorchis\u003c/em\u003e (GenBank acc. Num: XXXXXX), and the ITS2 gene sequence for the digenean \u003cem\u003eP. renicapite\u003c/em\u003e (GenBank acc. Num: XXXXXX) from loggerheads, were obtained. Both records did not match any sequences in GenBank because there are no previous sequences available for these species.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eDistribution of sea turtle parasites\u003c/h2\u003e \u003cp\u003eWe found 67 scientific papers reporting 58 parasite species for loggerheads and seven species for the leatherbacks worldwide (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, Tables\u0026nbsp;1, \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Of the 10 loggerhead RMUs, the Northwest Atlantic (NWA) had the most parasite records (n\u0026thinsp;=\u0026thinsp;34), followed by the Mediterranean (MED, n\u0026thinsp;=\u0026thinsp;30), SWA (n\u0026thinsp;=\u0026thinsp;17, of which five are new contributions resulting from the present work), and Southeast Indian (SEI, n\u0026thinsp;=\u0026thinsp;12). The remaining RMUs had less than ten parasite records (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e; Table\u0026nbsp;1).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eParasite species reported for \u003cem\u003eDermochelys coriacea\u003c/em\u003e by Regional Management Unit (RMU) defined by Wallace et al. (\u003cspan citationid=\"CR103\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRMU\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eDigenea\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eCalycodes anthos\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNorthwest Atlantic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eThrelfall \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e1979\u003c/span\u003e; Innis et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2010\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSouthwest Atlantic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWerneck et al. \u003cspan citationid=\"CR105\" class=\"CitationRef\"\u003e2012\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCymatocarpus\u003c/em\u003e sp.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eNorthwest Atlantic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eThrelfall \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e1979\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eEnodiotrema carettae\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eManfredi et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e1996\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eEnodiotrema instar\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eEnodiotrema\u003c/em\u003e sp.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eInnis et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2010\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cem\u003ePyelosomum renicapite\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNortheast Indian\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMohan 1970\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNorthwest Atlantic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacCallum \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e1921\u003c/span\u003e; Threlfall \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e1979\u003c/span\u003e; Almor et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1989\u003c/span\u003e; Dyer et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Manfredi et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Innis et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Poppi et al. \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2012\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSouthwest Atlantic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWerneck et al. \u003cspan citationid=\"CR105\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; \u003cb\u003ePresent study\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOrchiodasma amphiorchis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSouthwest Atlantic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003ePresent study\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFor leatherbacks, only three of the seven RMUs recorded parasites, with the NWA having the highest number of records (n\u0026thinsp;=\u0026thinsp;6), followed by the SWA (n\u0026thinsp;=\u0026thinsp;3, of which one is a new contribution from this work) and the Northeast Indian (NEI, n\u0026thinsp;=\u0026thinsp;1) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e; Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Gaps of parasite records were identified in the Northwest and Southwest Indian for loggerheads; and in the Southwest Indian, and East and West Pacific RMUs for leatherbacks.\u003c/p\u003e \u003cp\u003eLoggerheads from the SWA shared parasite species with several other RMUs: 13 species with the NWA, 11 with the MED, 5 with the SEI and one with the NEI. However, two parasite species were exclusive found in the SWA: \u003cem\u003eMonticellius indicum\u003c/em\u003e, and \u003cem\u003eP. elongatus\u003c/em\u003e (Table\u0026nbsp;1). Of the parasites identified in this study, \u003cem\u003eP. longiusculus\u003c/em\u003e was also documented in the NWA and NEI, \u003cem\u003eO. margoi\u003c/em\u003e in the NWA and MED, \u003cem\u003eO. amphiorchis\u003c/em\u003e, \u003cem\u003eK. leptura\u003c/em\u003e and \u003cem\u003eS. sulcata\u003c/em\u003e in the NWA, MED and SEI, and \u003cem\u003eP. renicapite\u003c/em\u003e was recorded in the NWA and at the confluence of the NWA, MED and NEA. Similarly, leatherbacks from the SWA shared parasite species with the MED, NWA and NEI. Only \u003cem\u003eO. amphiorchis\u003c/em\u003e was exclusive of the SWA.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study we provide new records of parasites for the loggerhead and leatherback turtles in the temperate SW Atlantic, region and species understudied. Particularly in Argentina, present study gives to known the second record of \u003cem\u003eO. amphiorchis\u003c/em\u003e since it was found in a loggerhead by Boero and Led (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1974\u003c/span\u003e). Also, new geographic records for loggerhead\u0026rsquo;s parasites including the digeneans \u003cem\u003eP. longiusculus\u003c/em\u003e and \u003cem\u003eP. renicapite\u003c/em\u003e, the nematodes \u003cem\u003eK. leptura\u003c/em\u003e and \u003cem\u003eS. sulcata\u003c/em\u003e, and the leech \u003cem\u003eO. margoi\u003c/em\u003e are provided. We report \u003cem\u003eP. renicapite\u003c/em\u003e in a leatherback for the first time in Argentina, and the finding of \u003cem\u003eO. amphiorchis\u003c/em\u003e represents a new host-parasite association. Genetic information for \u003cem\u003eK. leptura\u003c/em\u003e, \u003cem\u003eO. amphiorchis\u003c/em\u003e and \u003cem\u003eP. renicapite\u003c/em\u003e are given for the first time. Comparing on a global scale, the SWA share some parasite species with other RMUs in the northern and east hemispheres, but also exhibit exclusive parasite species. Gaps in parasite studies occur mostly in the East Atlantic, East Pacific and the Indian Ocean.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eParasite studies and the ecology of sea turtles\u003c/h2\u003e \u003cp\u003eMapping parasite diversity throughout sea turtle global distribution raises questions about many aspects of turtle ecology. One of these aspects is sea turtle migration and connectivity among RMUs. According to general parasitological knowledge, the biogeographic distribution of a parasite reflects that of its host (Marcogliese and Price \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e1997\u003c/span\u003e) to the extent that parasites are used as population biomarkers in several marine species (e.g. Catalano et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Does the biogeographic distribution of turtle parasites resemble the biogeographic distribution of their hosts? More precisely, can sea turtle parasites be used to better resolve current RMUs? Founding the answers to these questions is not straightforward. For example, loggerheads from the SWA share parasite species with those of the NWA, in accordance with the partial overlap defined by Wallace et al. (\u003cspan citationid=\"CR103\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) based on genetic and migration information (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). But SWA loggerheads also share parasite species with more distant ࣧnot overlappingࣧ RMUs, such as the MED, NEI and SEI (see Table\u0026nbsp;1). Given that most parasitic infection in sea turtles requires the occurrence of an intermediate host (Corner et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Santoro et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), the shared parasite species among distant but non-overlapping RMUs likely arise from similar ecological conditions in regions. This similarity allows for the independent development of the parasite life cycle, rather than from undocumented connectivity (through turtle migration) between RMUs.\u003c/p\u003e \u003cp\u003eAt the same time, each loggerhead RMUs exhibit exclusive parasite species (e.g. \u003cem\u003eM. indicum\u003c/em\u003e in the SWA, see Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e on Online Resource 1) that could act as biomarkers of turtles, especially in regions where RMUs overlap. For example, MED overlap with NWA and NEA (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) particularly in the western Mediterranean. Cribb et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) distinguish between western and eastern Mediterranean turtles, highlighting that the former may bring their parasites from the NWA. Which is the origin of a loggerhead found in this region? If there was sufficient parasitological knowledge of turtles, this question could be answered relatively easy by examining common and exclusive parasite species (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Species such as \u003cem\u003eAnisakis pegreffii\u003c/em\u003e and \u003cem\u003eStyphlotrema solitaria\u003c/em\u003e have been recorded both in MED and at the overlap zone of the three mentioned RMUs but not in NWA, so a turtle harboring both parasite species might belong to MED rather than to the Atlantic. Inversely, species such as \u003cem\u003eRhadinorhynchus pristis\u003c/em\u003e has been documented only at the overlap zone of the three RMUs and not in the relatively well-studied MED and NWA, indicating that a loggerhead found in this region might belong to the NEA (where no parasite has been recorded yet). Similarly, parasites present in the overlap zone of the three RMUs and as well in MED and NWA, could be expected to be found in the unexplored NEA. Implementation of parasites as biomarkers of turtle origin requires an exhaustive sampling of turtle parasites throughout RMUs, to ensure that exclusive parasite species are not the product of insufficient number of hosts examined.\u003c/p\u003e \u003cp\u003eParasites can also be useful in studies of feeding ecology. Most marine helminth parasites have intermediate hosts that depend on trophic interactions for their transmission (Marcogliese \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2004\u003c/span\u003e, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), so the identification of a parasite species can be indicative of host diet, especially in regions where such information is scarce. In the SWA, nine studies list prey of loggerheads and leatherbacks (e.g. Frazier \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e1985\u003c/span\u003e; Carranza et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; DiBeneditto et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), but none of these prey were reported to be intermediate host for these turtles. \u003cem\u003eSulcascaris sulcata\u003c/em\u003e is the only sea turtle parasite for which the life cycle is known (Berry and Cannon \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1981\u003c/span\u003e). This parasite has an indirect life cycle, with a bivalve or gastropod mollusc acting as intermediate host (Sprent \u003cspan citationid=\"CR92\" class=\"CitationRef\"\u003e1977\u003c/span\u003e; Santoro et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In this study, \u003cem\u003eS. sulcata\u003c/em\u003e was recorded always associated with the presence of gastropods in the digestive tract of loggerheads (e.g. \u003cem\u003eRapana venosa\u003c/em\u003e, \u003cem\u003ePachycymbiola\u003c/em\u003e spp, \u003cem\u003eZidona\u003c/em\u003e spp.; Personal observation), but unfortunately its intermediate host could not be identified.\u003c/p\u003e \u003cp\u003eAnother aspect that can be informed by parasite studies is the ontogenetic shift undergone by sea turtles within RMUs. In this study, the parasite prevalence in loggerhead was higher than that observed by Werneck et al. (\u003cspan citationid=\"CR104\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) in Brazil (76% vs 41.7%). These authors recorded three digenean species (\u003cem\u003eCalycodes anthos\u003c/em\u003e, \u003cem\u003eO. amphiorchis\u003c/em\u003e and \u003cem\u003eP. renicapite\u003c/em\u003e) and two nematode species (\u003cem\u003eK. leptura\u003c/em\u003e and \u003cem\u003eS. sulcata\u003c/em\u003e), with \u003cem\u003eC. anthos\u003c/em\u003e as the dominant species. We recorded the same parasite species (except for \u003cem\u003eC. anthos\u003c/em\u003e), but \u003cem\u003eS. sulcata\u003c/em\u003e was the dominant species. While differences in prevalence could be due to the origin of the hosts, the Argentine ones coming from strandings and the Brazilian ones coming from fishing by-catch (Werneck et al. \u003cspan citationid=\"CR104\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), also, differences in parasite communities among regions may obey to ecological reasons. For example, in the Mediterranean, differences in parasite communities among regions and turtles reflect the ontogenetic shift that loggerheads undergo from oceanic to neritic habitats (Santoro et al. 2010). Small pelagic juveniles exhibit a less diverse parasite community (only conformed by \u003cem\u003eE. megachondrus\u003c/em\u003e and \u003cem\u003eC. anthos\u003c/em\u003e) compared to larger neritic juveniles, which parasite community includes several species of nematodes as well (Santoro et al. \u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e2010a\u003c/span\u003e). In the SWA, more information on the size of loggerheads included in parasite studies is needed to evaluate if differences in parasite communities are informative of turtle ecology. Loggerheads analyzed in this study were large neritic juveniles and adults, but unfortunately information on turtle size provided by Werneck et al. (\u003cspan citationid=\"CR104\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) is incomplete, thus limiting the scope of any comparison.\u003c/p\u003e \u003cp\u003eLastly, parasite studies can be informative of the health status of turtle aggregations. We found a higher abundance of \u003cem\u003eS. sulcata\u003c/em\u003e individuals (A\u0026thinsp;=\u0026thinsp;2277) compared to that observed in other regions like Brazil (A\u0026thinsp;=\u0026thinsp;33, Werneck et al. \u003cspan citationid=\"CR104\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) and Mediterranean (A\u0026thinsp;=\u0026thinsp;196, Manfredi et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). \u003cem\u003eSulcascaris sulcata\u003c/em\u003e infection in loggerheads are known to be linked to ulcerative gastritis in the stomach mucosa. The severity of these lesions measured by the size of ulcers, correspond to the number of \u003cem\u003eS. sulcata\u003c/em\u003e individuals (Santoro et al. \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In our study, we observed non-perforated ulcers (4 cm length) associated with \u003cem\u003eS. sulcata\u003c/em\u003e in four out of the 24 turtles analysed. However, it is unlikely that parasitic infection contributes to the debilitation of the animals, since most of them exhibited good body condition, as evidenced by the presence of intracoelomic fat and recent food ingestion. On the other hand, the leech \u003cem\u003eO. margoi\u003c/em\u003e found in this study is vector of the Chelonid Herpes Virus Type 5 (CHPHV-5) and other turtle-associated viruses (Rittenburg et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Turtles infected with CHPHV-5 can develop fibropapillomatosis, characterized by the presence of internal and external benign tumors that, in severe cases, can lead to death due to wasting (Adnyana et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Aguirre and Lutz \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). While only one case of a green turtle with tumors was recently reported in Argentina (Origlia et al. \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), fibropapillomatosis is frequent in the rest of the SWA (Silva-Junior et al. 2019). Considering the presence of \u003cem\u003eO. margoi\u003c/em\u003e in loggerheads, virus infection could be expected even without the development of tumors (Gattamorta \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Therefore, studies to detect the virus in apparently uninfected turtles in Argentina would be necessary.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eLimitations of parasite studies in sea turtles and next steps\u003c/h2\u003e \u003cp\u003eMapping parasite diversity throughout the RMUs of loggerheads and leatherbacks raises interesting question about host ecology, but also present some limitations. As noted by Poulin and Morand (\u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2000\u003c/span\u003e), a key challenge in biogeographic studies of parasites is the risk that a map illustrating the distribution of species among regions merely reflects the variability in research activity among different parts of the world. In addition, from the non-studied RMUs, our estimation of parasite diversity in regions such as the Indian and the Pacific oceans is based on a few studies, examining less than five turtles. This suggests that several parasite species remain unrecorded due to an insufficient number of hosts examined. This is specially truth for leatherbacks, for which the limited parasite diversity observed can be attributed to the challenge of recovering and analysing hosts of considerable size (\u0026gt;\u0026thinsp;200 kg). Future parasite studies should prioritize understudied RMUs such as the NEA, the North and Southwest Indian, and the Pacific, for both loggerheads and leatherbacks. Additionally, comparisons of RMUs regarding the prevalence, intensity and abundances of parasites could not be performed in this study, given that these ecological parameters are rarely reported in both turtle species. Future parasite studies should also include these ecological data, along with precise information on the size of the turtles examined.\u003c/p\u003e \u003cp\u003eParticularly in the SWA, next steps should include the identification of intermediate hosts of turtle parasites to a better understanding of the trophic relationships. This is especially important for preys like gelatinous plankton, which is difficult to identify due its rapid digestibility (Arai \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Doyle et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Sea turtles and their digeneans parasites offer a unique opportunity to assess long-term feeding relationships. These parasites exhibit high host specificity in both their intermediate and definitive hosts, especially when the final host is a reptile (Chabaud and Bain \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1994\u003c/span\u003e). Further studies are essential to actively search for latent viruses in turtles and their possible vectors, as well as other pathogenic agents. A comprehensive health diagnosis of populations is crucial to developing effective conservation plans.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe contribution of new records of sea turtle parasites, both geographically and in terms of new parasite-host associations, represent a significant step towards a better understanding of turtle ecology. However, to enhance the utility of parasite studies in understanding turtle ecology, it is crucial to gather more information on the parasites of current and probable preys of turtles. This will help advance our knowledge on the biodiversity and structure of food webs that support sea turtles. In this work, we show how knowledge of a parasite species ecology, such as \u003cem\u003eS. sulcata\u003c/em\u003e, can provide us with valuable information about sea turtles, including diet, ontogenetic, and health status. Furthermore, integrating the systematics of parasites with the existing knowledge from RMUs can facilitate the development of tools for predicting the RMUs of the turtles found and the parasite species present in unstudied regions. However, our knowledge of the global parasite diversity of loggerhead and leatherback turtles is still incomplete, with parasite studies lacking in several regions. We encourage for genetic characterization of parasites to help future research on phylogenetic relationships.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eE.O.P and V.G.C conceived and designed research. E.O.P, V.G.C, K.C.A, S.R.H, A.R, M.V, I.M.B, J.P.L, L.D and A.F carried out fieldwork. E.O.P, V.G.C, M.R.W and J.I.D analyzed data and wrote the manuscript. All authors read and approved the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThis manuscript would not be possible without the collaboration of artisanal fishers from San Clemente del Tuy\u0026uacute;, who provided sea turtle individuals found dead in fishing gear. We are also grateful to technicians and researchers from Fundaci\u0026oacute;n Mundo Marino and Parque Educativo Mundo Marino, Prefectura Naval Argentina, park rangers and lifeguards from Buenos Aires province, who assisted during fieldwork. We also thank the support given by the Mar del Plata Aquarium thorough Alejandro Saubidet. Funding was partially provided by the Subsidio del Fondo para la Investigaci\u0026oacute;n Cient\u0026iacute;fica y Tecnol\u0026oacute;gica (FONCyT) to the project N\u0026ordm; 1575-2017 of VGC. This is INIDEP contribution no. XXXX.\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or nonfinancial interest to disclose.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAdnyana W, Ladds PW, Blair D (1997) Observations of fibropapillomatosis in green turtles (\u003cem\u003eChelonia mydas\u003c/em\u003e) in Indonesia. Australian Vet J 75:737\u0026ndash;742. https://doi.org/10.1111/j.1751-0813.1997.tb12258.x\u003c/li\u003e\n\u003cli\u003eAguirre AA, Lutz PL (2004) Marine turtles as sentinels of ecosystem health: is fibropapillomatosis an indicator? EcoHealth 1:275\u0026ndash;283. https://doi.org/10.1007/s10393-004-0097-3\u003c/li\u003e\n\u003cli\u003eAlmor P, Raga JA, Abril E et al (1989) Parasitisme de la tortue luth, \u003cem\u003eDermochelys coriacea\u003c/em\u003e (Linnaeus, 1766) dans les eaux europeennes par \u003cem\u003ePyelosomum renicapite\u003c/em\u003e (Leidy, 1856). Vie et Milieu. Life \u0026amp; Environment 3:57\u0026ndash;59 \u003c/li\u003e\n\u003cli\u003eAltschul SF, Madden TL, Sch\u0026auml;ffer AA et al (1997) Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res 25:3389\u0026ndash;3402. https://doi.org/10.1093/nar/25.17.3389\u003c/li\u003e\n\u003cli\u003eArai MN (2005) Predation on pelagic coelenterates: a review. J Mar Biol Assoc United Kingdom 85:523\u0026ndash;536. https://doi.org/10.1017/S0025315405011458\u003c/li\u003e\n\u003cli\u003eAra\u0026uacute;jo TL (1941) Nota sobre um trematoide Aspidogastridae de tartaruga marinha. Bol Ind Anim 4:3\u0026ndash;4 \u003c/li\u003e\n\u003cli\u003eAznar FJ, Badillo FJ, Raga JA (1998) Gastrointestinal helminths of loggerhead turtles (\u003cem\u003eCaretta caretta\u003c/em\u003e) from the western Mediterranean: constraints on community structure. J Parasitol 84:474\u0026ndash;479. https://doi.org/10.2307/3284708\u003c/li\u003e\n\u003cli\u003eBaptistotte C, Thom\u0026eacute; JCA, Bjorndal KA (2003) Reproductive Biology and Conservation Status of the Loggerhead Sea Turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e) in Esp\u0026iacute;rito Santo State, Brazil. Chelonian Conserv Biol 4:1\u0026ndash;7\u003c/li\u003e\n\u003cli\u003eBaylis HA (1928) XLI. \u0026mdash; Records of some parasitic worms from British vertebrates. J Nat Hist 1:329\u0026ndash;343 \u003c/li\u003e\n\u003cli\u003eBerry GN, Cannon LRG (1981) The life history of \u003cem\u003eSulcascaris sulcata\u003c/em\u003e (Nematoda: Ascaridoidea), a parasite of marine molluscs and turtles. Int J Parasitol 11:43\u0026ndash;54\u003c/li\u003e\n\u003cli\u003eBlair D (1984) \u003cem\u003eElytrophallus carettae\u003c/em\u003e sp. n. (Digenea: Hemiuridae) from the stomach of loggerhead turtles (\u003cem\u003eCaretta caretta\u003c/em\u003e (L.)) from Australia. P Helm Soc Washington 51:135\u0026ndash;139\u003c/li\u003e\n\u003cli\u003eBlair D, Limpus CJ (1982) Some digeneans (Platyhelminthes) parasitic in the Loggerhead Turtle, \u003cem\u003eCaretta caretta\u003c/em\u003e (L). in Australia. Aust J Zool 30:653\u0026ndash;680\u003c/li\u003e\n\u003cli\u003eBoero JJ, Led JE (1974) Parasites of the autochthonous fauna. Rev Agron Veter 3:16\u0026ndash;17\u003c/li\u003e\n\u003cli\u003eBolten AB (2000) T\u0026eacute;cnicas para la medici\u0026oacute;n de tortugas marinas. In: Eckert KL, Bjorndal KA, Abreu-Grobois FA, Donnelly M (eds) T\u0026eacute;cnicas de investigaci\u0026oacute;n y manejo para la conservaci\u0026oacute;n de las tortugas marinas, Grupo especialista en tortugas marinas IUCN/CSE, Publicaci\u0026oacute;n no. 4, pp 110\u0026ndash;114\u003c/li\u003e\n\u003cli\u003eBolten AB (2003) Variation in sea turtle life history patterns: neritic vs. oceanic developmental stages. In: Lutz PL, Musick JA, Wyneken J (eds) The biology of sea turtles, Vol 2, 1st edn. CRC Press, Boca Raton, pp 243\u0026ndash;257\u003c/li\u003e\n\u003cli\u003eBonfield JK, Smith KF, Staden R (1995) A new DNA sequence assembly program. Nucleic Acids Res 24:4992\u0026ndash;4999 \u003c/li\u003e\n\u003cli\u003eBursey CR, Manire CA (2006) \u003cem\u003eAngiostoma carettae\u003c/em\u003e n. sp. (Nematoda: Angiostomatidae) from the loggerhead sea turtle \u003cem\u003eCaretta caretta\u003c/em\u003e (Testudines: Cheloniidae), Florida, USA. Comp Parasitol, 73:253\u0026ndash;256. https://doi.org/10.1654/4200.1\u003c/li\u003e\n\u003cli\u003eBursey CR, Richardson KE, Richardson DJ (2006) First North American records of \u003cem\u003eKathlania leptura\u003c/em\u003e and \u003cem\u003eTonaudia tonaudia\u003c/em\u003e (Nematoda: Kathlanidae), parasites of marine turtles. Comp Parasitol 73:134\u0026ndash;135. https://doi.org/10.1654/0002.1\u003c/li\u003e\n\u003cli\u003eBush AO, Lafferty KD, Lotz JM et al (1997) Parasitology meets ecology on its own terms: Margolis et al. Revisited. J Parasitol 83:575\u0026ndash;583. https://doi.org/10.2307/3284227\u003c/li\u003e\n\u003cli\u003eCarranza A, Estrades A, Scarabino F, Segura A (2010) Loggerhead turtles \u003cem\u003eCaretta caretta\u003c/em\u003e (Linnaeus) preying on the invading gastropod \u003cem\u003eRapana venosa\u003c/em\u003e (Valenciennes) in the R\u0026iacute;o de la Plata Estuary. Mar Ecol 32:142\u0026ndash;147. https://doi.org/10.1111/j.1439-0485.2010.00424.x\u003c/li\u003e\n\u003cli\u003eCary LR (1930) Report on Investigations at Tortugas. Studies on Miracidia. Carnegie Inst Washington 29:325\u0026ndash;329\u003c/li\u003e\n\u003cli\u003eCatalano SR, Whittington ID, Donnellan SC, Gillanders BM (2014) Parasites as biological tags to assess host population structure: guidelines, recent genetic advances and comments on a holistic approach. Int J Parasitol: Parasites and Wildlife, 3:220\u0026ndash;226. https://doi.org/10.1016/j.ijppaw.2013.11.001\u003c/li\u003e\n\u003cli\u003eCavaco B, De Carvalho LM, Werneck MR (2021) Some digenetic trematodes found in a loggerhead sea turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e) from Brazil. Helminthologia 58:217\u0026ndash;224. https://doi.org/10.2478/helm-2021-0023\u003c/li\u003e\n\u003cli\u003eChabaud AG, Bain O (1994) The evolutionary expansion of the Spirurida. Int J Parasitol 24:1179\u0026ndash;1201. https://doi.org/10.1016/0020-7519(94)90190-2\u003c/li\u003e\n\u003cli\u003eChattopadhyaya DR (1972) Studies on the trematode parasites of reptiles found in India. Contribution to our knowledge of the family Pronocephalidae Looss, 1902. Riv Parassitol 33: 99\u0026ndash;124\u003c/li\u003e\n\u003cli\u003eCorner RD, Cribb TH, Cutmore SC (2022) Vermetid gastropods as key intermediate hosts for a lineage of marine turtle blood flukes (Digenea: Spirorchiidae), with evidence of transmission at a turtle rookery. Int J Parasitol 52:225\u0026ndash;241. https://doi.org/10.1016/j.ijpara.2021.08.008\u003c/li\u003e\n\u003cli\u003eCribb TH, Adlard RD, Bray RA (1998) A DNA-based demonstration of a three-host life-cycle for the Bivesiculidae (Platyhelminthes: Digenea). Int J Parasitol 28:1791\u0026ndash;1795. https://doi.org/10.1016/S0020-7519(98)00127-1 \u003c/li\u003e\n\u003cli\u003eCribb TH, Crespo-Picazo JL, Cutmore SC, Stacy BA, Chapman PA, Garc\u0026iacute;a-P\u0026aacute;rraga D (2017) Elucidation of the first definitively identified life cycle for a marine turtle blood fluke (Trematoda: Spirorchiidae) enables informed control. Int J Parasitol 47:61\u0026ndash;67. https://doi.org/10.1016/j.ijpara.2016.11.002\u003c/li\u003e\n\u003cli\u003eDavies RW, Chapman CG (1974) First record from North America of the piscicolid leech, \u003cem\u003eOzobranchus margoi\u003c/em\u003e, a parasite of marine turtles. J Fish Boar Canada 31:104\u0026ndash;106. https://doi.org/10.1139/f74-016\u003c/li\u003e\n\u003cli\u003eDi Beneditto APM, De Moura JF, Siciliano S (2015) Feeding habits of the sea turtles \u003cem\u003eCaretta caretta\u003c/em\u003e and \u003cem\u003eLepidochelys olivacea\u003c/em\u003e in south-eastern Brazil. Mar Biodiver Rec 8: e122\u003c/li\u003e\n\u003cli\u003eDi Renzo L, Di Gialleonardo L, Marchiori E et al (2021) \u003cem\u003eCucullanus carettae\u003c/em\u003e Baylis, 1923, in a loggerhead sea turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e) from the Adriatic sea: first detection and molecular characterization. Parasitol Res 120:341\u0026ndash;345. https://doi.org/10.1007/s00436-020-06936-5 \u003c/li\u003e\n\u003cli\u003eDoyle TK, Houghton JD, Buckley SM, Hays GC, Davenport J (2007) The broad-scale distribution of five jellyfish species across a temperate coastal environment. Hydrobiologia 579: 29\u0026ndash;39. https://doi.org/10.1007/s10750-006-0362-2\u003c/li\u003e\n\u003cli\u003eDyer WG, Williams EH, Bunkley-Williams L et al (1995) Some digeneans (Trematoda) at the Atlantic Hawksbill turtle, \u003cem\u003eEretmochelys imbricata imbricata \u003c/em\u003e(Testudines: Cheloniidae) from Puerto Rico. J Helminthol Soc Wash 62:13\u0026ndash;17\u003c/li\u003e\n\u003cli\u003eErnst CH, Ernst EM (1977) Ectoparasites associated with neotropical turtles of the genus \u003cem\u003eCallopsis\u003c/em\u003e (Testudines, Emydidae, Batagurinae). Biotropica 9:139\u0026ndash;142. https://doi.org/10.2307/2387671\u003c/li\u003e\n\u003cli\u003eEsteban N, Mortimer JA, Stokes HJ, Lalo\u0026euml; JO, Unsworth RK, Hays GC (2020) A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels. Mar Biol 167:1\u0026ndash;17. https://doi.org/10.1007/s00227-020-03786-8\u003c/li\u003e\n\u003cli\u003eEuzet L, Combes C, Triquell A (1972) On two trematodes from \u003cem\u003eCaretta caretta\u003c/em\u003e (L.) from the French Mediterranean coast. Vie et Milieu, A (Biologie Marine) 23:157\u0026ndash;167\u003c/li\u003e\n\u003cli\u003eFloyd RM, Rogers AD, Lambshead PJD, Smith CR (2005) Nematode-specific PCR primers for the 18S small subunit rRNA gene. Mol Ecol Notes 5:611\u0026ndash;612. https://doi.org/10.1111/j.1471-8286.2005.01009.x\u003c/li\u003e\n\u003cli\u003eFrazier J (1985) Misidentifications of sea turtles in the East Pacific: \u003cem\u003eCaretta caretta\u003c/em\u003e and \u003cem\u003eLepidochelys olivacea\u003c/em\u003e. J Herpetol 19:1\u0026ndash;11.\u003c/li\u003e\n\u003cli\u003eFuentes MM, Pike DA, Dimatteo A, Wallace BP (2013) Resilience of marine turtle regional management units to climate change. Glob Change Biol 19:1399\u0026ndash;1406. https://doi.org/10.1111/gcb.12138\u003c/li\u003e\n\u003cli\u003eGagne RB, Crooks KR, Craft ME, Chiu ES et al (2022) Parasites as conservation tools. Conserv Biol 36: e13719. https://doi.org/10.1111/cobi.13719\u003c/li\u003e\n\u003cli\u003eGattamorta MA (2015) Ecolog\u0026iacute;a, prevalencia e caracterizacao molecular de Chelonid fibropapilloma-associated herpesvirus (CFPHV) em tartarugas verdes (\u003cem\u003eChelonia mydas\u003c/em\u003e) em \u0026aacute;reas da costa brasileira (Thesis). Piracicaba, Brazil.\u003c/li\u003e\n\u003cli\u003eGentile A, Amato T, Gustinelli A, Fioravanti ML et al (2021) Helminth Infection of the Loggerhead Sea Turtle \u003cem\u003eCaretta caretta\u003c/em\u003e along the Coasts of Sicily and the North West Adriatic Sea. Animals 11:1408. https://doi.org/10.3390/ani11051408\u003c/li\u003e\n\u003cli\u003eGračan R, Mladineo I, Kučinić M, Lazar B, Lacković G (2012) Gastrointestinal helminth community of loggerhead sea turtle \u003cem\u003eCaretta caretta\u003c/em\u003e in the Adriatic Sea. Dis Aquat Org 99:227\u0026ndash;236. https://doi.org/10.3354/dao02490\u003c/li\u003e\n\u003cli\u003eGreiner EC (2013) Parasites of marine turtles. In: Wyneken J, Lohmann KJ, Musick JA (eds) The biology of sea turtles, Vol 3, 1\u003csup\u003est\u003c/sup\u003e edn. CRC Press, Boca Raton, pp 425\u0026ndash;444\u003c/li\u003e\n\u003cli\u003eHamann M, Godfrey MH, Seminoff JA et al (2010). Global research priorities for sea turtles: informing management and conservation in the 21st century. Endanger Species Res 11: 245\u0026ndash;269. https://doi.org/10.3354/esr00279\u003c/li\u003e\n\u003cli\u003eInglis WG (1957) A revision of the nematode genera \u003cem\u003eKathlania\u003c/em\u003e and \u003cem\u003eTonaudia\u003c/em\u003e. Ann Magaz Nat Hist 10:785\u0026ndash;800\u003c/li\u003e\n\u003cli\u003eInnis C, Merigo C, Dodge K et al (2010) Health evaluation of leatherback turtles (\u003cem\u003eDermochelys coriacea\u003c/em\u003e) in the northwestern Atlantic during direct capture and fisheries gear disentanglement. Chelonian Conserv Biol 9:205\u0026ndash;222\u003c/li\u003e\n\u003cli\u003eJacobson ER, Homer BL, Stacy BA et al (2006) Neurological disease in wild loggerhead sea turtles \u003cem\u003eCaretta caretta\u003c/em\u003e. Dis Aquat Org 70:139\u0026ndash;154. https://doi.org/10.3354/dao070139\u003c/li\u003e\n\u003cli\u003eKaraa S, Jribi I, Marouani S et al (2019) Preliminary study on parasites in loggerhead turtles (\u003cem\u003eCaretta caretta\u003c/em\u003e) from the Southern Tunisian waters. Am J Biomed Sci \u0026amp; Res 5:373\u0026ndash;376\u003c/li\u003e\n\u003cli\u003eKawazu I, Ueda K, Hirai S, Maeda K, Yanagisawa M, Miyaraha H (2018) Captive Loggerhead Turtle Hatchlings Infected by Parasitic Cardiovascular Blood Flukes. Mar Turt Newslet 155:20\u0026ndash;21\u003c/li\u003e\n\u003cli\u003eLent H, Teixeira de Freitas JF (1948) Uma cole\u0026ccedil;\u0026atilde;o de nemat\u0026oacute;deos, parasitos de vertebrados do Museu de Hist\u0026oacute;ria natural de Montevid\u0026eacute;u. Mem Inst Oswaldo Cruz 46:1\u0026ndash;71\u003c/li\u003e\n\u003cli\u003eLester RJG, Blair D, Heald D (1980) Nematodes from scallops and turtles from Shark Bay, Western Australia. Aust J Mar Freshwater Res 31:713\u0026ndash;717\u003c/li\u003e\n\u003cli\u003eLinton E (1910) Helminth fauna of the Dry Tortugas. 11. Trematodes. Pap Tortugas Lab 4:11\u0026ndash;98\u003c/li\u003e\n\u003cli\u003eLittlewood DTJ (1994) Molecular phylogenetics of cupped oysters based on partial 28S rRNA gene sequences. Mol Phylogenet Evol 3:221\u0026ndash;229. https://doi.org/10.1006/mpev.1994.1024\u003c/li\u003e\n\u003cli\u003eLooss A (1899) Weitere Beitr\u0026auml;ge zur Kenntniss der Trematoden-Fauna Aegyptens, zugleich Versuch einer nat\u0026uuml;rlichen Gliederung des Genus Distomum Retzius. Zoologische Jahrb\u0026uuml;cher 12:521\u0026ndash;784\u003c/li\u003e\n\u003cli\u003eLuhman M (1935) Two new trematodes from the loggerhead turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e). The J Parasitol 21:274\u0026ndash;276. https://doi.org/10.2307/3271358\u003c/li\u003e\n\u003cli\u003eMacCallum GA (1921) Studies in helminthology. Zoopathologica 1:137\u0026ndash;284\u003c/li\u003e\n\u003cli\u003eManfredi MT, Piccolo G, Prato F, Loria GR (1996) Parasites in Italian sea turtles. I. The leatherback turtle \u003cem\u003eDermochelys coriacea\u003c/em\u003e (Linnaeus, 1766). Parassitologia 38:581\u0026ndash;583\u003c/li\u003e\n\u003cli\u003eManfredi MT, Piccolo G, Meotti C (1998) Parasites of Italian sea turtles. II. Loggerhead turtles (\u003cem\u003eCaretta caretta\u003c/em\u003e [Linnaeus, 1758]). Parassitologia 40:305\u0026ndash;308.\u003c/li\u003e\n\u003cli\u003eManire CA, Kinsel MJ, Anderson ET, Clauss TM, Byrd L (2008) Lungworm infection in three loggerhead sea turtles, \u003cem\u003eCaretta caretta\u003c/em\u003e. J Zoo Wildl Med 39:92\u0026ndash;98. https://doi.org/10.1638/2007-0092.1\u003c/li\u003e\n\u003cli\u003eManter HW (1932) Continued studies on Trematodes of Tortugas. Carnegie Inst Washington Year Book 31:287\u0026ndash;288\u003c/li\u003e\n\u003cli\u003eManter HW, Larson MI (1950) Two new blood flukes from a marine turtle, \u003cem\u003eCaretta caretta\u003c/em\u003e. J Parasitol 36:595\u0026ndash;599. https://doi.org/10.2307/3273293\u003c/li\u003e\n\u003cli\u003eMarangi M, Carlino P, Profico C et al (2020) First multicenter coprological survey on helminth parasite communities of free-living loggerhead sea turtles \u003cem\u003eCaretta caretta\u003c/em\u003e (Linnaeus, 1758) from the Adriatic Sea and Northern Ionian Sea. Int J Parasitol: Parasites Wildlife 11:207\u0026ndash;212. https://doi.org/10.1016/j.ijppaw.2020.02.006\u003c/li\u003e\n\u003cli\u003eMarcer F, Tosi F, Franzo G, Vetri A, Ravagnan S, Santoro M, Marchiori E (2020) Updates on ecology and life cycle of \u003cem\u003eSulcascaris sulcata\u003c/em\u003e (Nematoda: Anisakidae) in Mediterranean Grounds: Molecular Identification of larvae infecting edible scallops. Front Vet Sci 7:64. https://doi.org/10.3389/fvets.2020.00064\u003c/li\u003e\n\u003cli\u003eMarchiori E, Negrisolo E, Cassini R et al (2017) Cardiovascular flukes (Trematoda: Spirorchiidae) in \u003cem\u003eCaretta caretta\u003c/em\u003e Linnaeus, 1758 from the mediterranean sea. Parasites Vectors 10:1\u0026ndash;14. https://doi.org/10.1186/s13071-017-2396-x\u003c/li\u003e\n\u003cli\u003eMarcogliese DJ (2004) Parasites: small players with crucial roles in the ecological theater. EcoHealth 1:151-164. https://doi.org/10.1007/s10393-004-0028-3\u003c/li\u003e\n\u003cli\u003eMarcogliese DJ (2005) Transmission of marine parasites. In: Rohde K (ed) Marine Parasitology, 1st edn. Csiro, New York, pp 280\u0026ndash;286\u003c/li\u003e\n\u003cli\u003eMarcogliese DJ (2023) Major drivers of biodiversity loss and their impacts on helminth parasite populations and communities. J Helminthol 97: e34. https://doi.org/10.1017/S0022149X2300010X\u003c/li\u003e\n\u003cli\u003eMarcogliese DJ, Price J (1997) The paradox of parasites. Global biodiversity 7:7\u0026ndash;15\u003c/li\u003e\n\u003cli\u003eMonticelli FS (1896) Di un ematozoo della \u003cem\u003eThalassochelys caretta\u003c/em\u003e Linn. Internationale Monatsschrift fur Anatomie und Physiologie 13:141\u0026ndash;172\u003c/li\u003e\n\u003cli\u003eMohan RS (1971) Occurrence of the digenetic trematode \u003cem\u003eAstrorchis renicapite\u003c/em\u003e (Leidy) family: Pronocephalidae) in the leathery turtle \u003cem\u003eDermochelys coriacea\u003c/em\u003e (Linne) from the Indian Ocean. Cent Mar Fisher Res Inst 6:489\u0026ndash;490\u003c/li\u003e\n\u003cli\u003eMusick JA, Limpus CJ (1997) Habitat utilization and migration in juvenile sea turtles. In: Lutz PL, Musick JA (eds) The Biology of Sea Turtles, 1st edn. CRC Press, Boca Raton, pp 137\u0026ndash;164\u003c/li\u003e\n\u003cli\u003eOriglia JA, Loureiro JP, Tizzano MA et al (2023) Fibropapillomatosis Associated with Chelonid alphaherpesvirus 5 (ChHV5) in a Green Turtle \u003cem\u003eChelonia mydas\u003c/em\u003e in Argentine Waters. J Wildl Dis 59:363\u0026ndash;366. https://doi.org/10.7589/JWD-D-22-00083 \u003c/li\u003e\n\u003cli\u003ePiccolo G, Manfredi MT (2001) New reports on parasites of marine turtles stranded along the Italian coasts. In: Margaritoulis D, Demetropoulos A (eds) First Mediterranean conference on marine turtles, 1\u003csup\u003est\u003c/sup\u003e edn. ICRAM, Roma, pp 207\u0026ndash;211 \u003c/li\u003e\n\u003cli\u003ePlatt TR, Blair D (1998) Redescription of \u003cem\u003eHapalotrema mistroides\u003c/em\u003e (Monticelli, 1896) and \u003cem\u003eHapalotrema synorchis\u003c/em\u003e Luhman, 1935 (Digenea: Spirorchiidae), with comments on other species in the genus. J Parasitol 84:594\u0026ndash;600. https://doi.org/10.2307/3284729\u003c/li\u003e\n\u003cli\u003ePoppi L, Zaccaroni A, Pasotto D et al (2012) Post-Mortem investigations on a leatherback turtle \u003cem\u003eDermochelys coriacea \u003c/em\u003estranded along the Northern Adriatic coastline. Dis Aquat Org 100:71\u0026ndash;76. https://doi.org/10.3354/dao02479\u003c/li\u003e\n\u003cli\u003ePoulin R, Morand S (2000) The diversity of parasites. Q Rev Biol 75:277\u0026ndash;293\u003c/li\u003e\n\u003cli\u003ePratt HS (1914) Trematodes of the loggerhead turtle (Caretta caretta) of the Gulf of Mexico. Arch Parasitol 41:1\u0026ndash;27\u003c/li\u003e\n\u003cli\u003eRittenburg LT, Kelley JR, Mansfield KL, Savage AE (2021) Marine leech parasitism of sea turtles varies across host species, seasons, and the tumor disease fibropapillomatosis. Dis Aquat Org 143:1\u0026ndash;12. https://doi.org/10.3354/dao03549\u003c/li\u003e\n\u003cli\u003eRobinson NJ, Pfaller JB (2022) Sea turtle epibiosis: Global patterns and knowledge gaps. Front Ecol Evol 10: 844021. https://doi.org/10.3389/fevo.2022.844021\u003c/li\u003e\n\u003cli\u003eRodenbusch CR, Marks FS, Canal CW, Reck J (2012) Marine leech \u003cem\u003eOzobranchus margoi\u003c/em\u003e parasitizing loggerhead turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e) in Rio Grande do Sul, Brazil. Rev Brasileira Parasitol Vet 21:301\u0026ndash;303.\u003c/li\u003e\n\u003cli\u003eSantoro M, Badillo FJ, Mattiucci S et al (2010a) Helminth communities of loggerhead turtles (\u003cem\u003eCaretta caretta\u003c/em\u003e) from Central and Western Mediterranean Sea: The importance of host\u0026apos;s ontogeny. Parasitol Int 59:367\u0026ndash;375. https://doi.org/10.1016/j.parint.2010.04.009 \u003c/li\u003e\n\u003cli\u003eSantoro M, Mattiucci S, Paoletti M et al (2010b). Molecular identification and pathology of \u003cem\u003eAnisakis pegreffii\u003c/em\u003e (Nematoda: Anisakidae) infection in the Mediterranean loggerhead sea turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e). Vet Parasitol 174:65\u0026ndash;71. https://doi.org/10.1016/j.vetpar.2010.08.018\u003c/li\u003e\n\u003cli\u003eSantoro M, Di Nocera F, Iaccarino D et al (2017) Pathology and molecular analysis of \u003cem\u003eHapalotrema mistroides\u003c/em\u003e (Digenea: Spirorchiidae) infecting a Mediterranean loggerhead turtle \u003cem\u003eCaretta caretta\u003c/em\u003e. Dis Aquat Org 124:101\u0026ndash;108. https://doi.org/10.3354/dao03117\u003c/li\u003e\n\u003cli\u003eSantoro M, Marchiori E, Iaccarino D et al (2019) Epidemiology of \u003cem\u003eSulcascaris sulcata\u003c/em\u003e (Nematoda: Anisakidae) ulcerous gastritis in the Mediterranean loggerhead sea turtle (\u003cem\u003eCaretta caretta\u003c/em\u003e). Parasitol Res 118:1457\u0026ndash;1463. https://doi.org/10.1007/s00436-019-06283-0\u003c/li\u003e\n\u003cli\u003eSantoro M, Marchiori E, Cassini R et al (2020) Epidemiology of blood flukes (Digenea: Spirorchiidae) in sea turtles from Tyrrhenian and Adriatic Seas, off Italy. Parasites Vectors 13:1\u0026ndash;10. https://doi.org/10.1186/s13071-020-3922-9\u003c/li\u003e\n\u003cli\u003eSantoro M, Palomba M, Modica MV (2022) Larvae of \u003cem\u003eSulcascaris sulcata\u003c/em\u003e (Nematoda: Anisakidae), a parasite of sea turtles, infect the edible purple dye murex \u003cem\u003eBolinus brandaris\u003c/em\u003e in the Tyrrhenian Sea. Food Control 132:108547. https://doi.org/10.1016/j.foodcont.2021.108547\u003c/li\u003e\n\u003cli\u003eSey O (1977) Examination of helmints parasites of marine turtles caught along the Egyptian coast. Acta Zoologica Academiae Scientiarium Hungaricae 23:3\u0026ndash;4 \u003c/li\u003e\n\u003cli\u003eSilva-J\u0026uacute;nior ESD, de Farias DSD, Costa Bomfim AD et al (2019) Stranded marine turtles in northeastern Brazil: incidence and spatial\u0026ndash;temporal distribution of fibropapillomatosis. Chel Conserv Biol 18:249\u0026ndash;258. https://doi.org/10.2744/CCB-1359.1 \u003c/li\u003e\n\u003cli\u003eSimha SS (1977) On a new genus and species of a blood-fluke \u003cem\u003eNeocaballerotrema caballeroi\u003c/em\u003e, from a marine turtle in India. Universidad Nacional Autonoma de Mexico, Instituto de Biolog\u0026iacute;a, Mexico, pp 307\u0026ndash;310\u003c/li\u003e\n\u003cli\u003eSimha SS, Chattopadhyaya DR (1978) Studies on the trematode parasites of reptiles found in India. Contribution to the knowledge of blood flukes from the marine turtles, from the Gulf of Manar, South India. J Zool Soc India 30:69\u0026ndash;82\u003c/li\u003e\n\u003cli\u003eSprent JFA (1977) Ascaridoid nematodes of amphibians and reptiles: \u003cem\u003eSulcascaris\u003c/em\u003e. J Helminthol 51:379\u0026ndash;387. https://doi.org/10.1017/S0022149X00007744 \u003c/li\u003e\n\u003cli\u003eStacy BA, Foley AM, Greiner E et al (2010) Spirorchiidiasis in stranded loggerhead \u003cem\u003eCaretta caretta\u003c/em\u003e and green turtles \u003cem\u003eChelonia mydas\u003c/em\u003e in Florida (USA): host pathology and significance. Dis Aquat Org 89:237\u0026ndash;259. https://doi.org/10.3354/dao02195\u003c/li\u003e\n\u003cli\u003eSterioti A, Doxa CC, Grigoriou P, Vardanis G, Cascarano MC, Katharios P (2017) \u003cem\u003eOzobranchus margoi\u003c/em\u003e infections in loggerhead turtles (\u003cem\u003eCaretta caretta\u003c/em\u003e) in Greece and potential treatment options. J Exot Pet Med 26:196\u0026ndash;199. https://doi.org/10.1053/j.jepm.2017.05.006\u003c/li\u003e\n\u003cli\u003eThom\u0026eacute; JC, Baptistotte C, Moreira LMP, Scalfoni JT, Almeida AP, Rieth DB, Barata PC (2007) Nesting biology and conservation of the leatherback sea turtle (\u003cem\u003eDermochelys coriacea\u003c/em\u003e) in the state of Esp\u0026iacute;rito Santo, Brazil. Chelonian Conserv Biol 6:15\u0026ndash;27\u003c/li\u003e\n\u003cli\u003eThrelfall W (1979) Three species of Digenea from the Atlantic leatherback turtle (\u003cem\u003eDermochelys coriacea\u003c/em\u003e). Canadian J Zool 57:1825\u0026ndash;1829\u003c/li\u003e\n\u003cli\u003eTravassos L, Freitas T, Kohn A (1969) Tremat\u0026oacute;deos do Brasil. Mem Inst Oswaldo Cruz 67:1\u0026ndash;886\u003c/li\u003e\n\u003cli\u003eValente AL, Delgado C, Moreira C et al (2009) Helminth component community of the loggerhead sea turtle, \u003cem\u003eCaretta caretta\u003c/em\u003e, from Madeira Archipelago, Portugal. J Parasitol 95:249\u0026ndash;252. https://doi.org/10.1645/GE-1519.1\u003c/li\u003e\n\u003cli\u003eViana L (1924) Tentativa de cataloga\u0026ccedil;\u0026atilde;o das especies brazileiras de tremat\u0026oacute;deos. Mem Inst Oswaldo Cruz 17:95\u0026ndash;227\u003c/li\u003e\n\u003cli\u003eWallace BP, DiMatteo AD, Hurley BJ et al (2010a) Regional management units for marine turtles: a novel framework for prioritizing conservation and research across multiple scales. Plos one 5: e15465. https://doi.org/10.1371/journal.pone.0015465\u003c/li\u003e\n\u003cli\u003eWallace BP, Lewison RL, McDonald SL et al (2010b) Global patterns of marine turtle bycatch. Conserv Lett 3:131\u0026ndash;142. https://doi.org/10.1111/j.1755-263X.2010.00105.x\u003c/li\u003e\n\u003cli\u003eWallace BP, Stacy BA, Cuevas E et al (2020) Oil spills and sea turtles: documented effects and considerations for response and assessment efforts. Endang Species Res 41:17\u0026ndash;37. https://doi.org/10.3354/esr01009\u003c/li\u003e\n\u003cli\u003eWallace BP, Posnik ZA, Hurley BJ et al (2023) Marine turtle regional management units 2.0: an updated framework for conservation and research of wide-ranging megafauna species. Endanger Species Res 52: 209\u0026ndash;223. https://doi.org/10.3354/esr01243\u003c/li\u003e\n\u003cli\u003eWerneck MR, Thomazini CM, Mori ES, Gon\u0026ccedil;alves VT, GOMES BM (2008) Gastrointestinal helminth parasites of loggerhead turtle \u003cem\u003eCaretta caretta\u003c/em\u003e Linnaeus 1758 (Testudines, Cheloniidae) in Brazil. Pan-American J Aquatic Science 3:351\u0026ndash;354\u003c/li\u003e\n\u003cli\u003eWerneck MR, Verissimo L, Baldassin P et al (2012) Digenetic trematodes of \u003cem\u003eDermochelys coriacea\u003c/em\u003e from the Southwestern Atlantic Ocean. Mar Turtle News 132: 13\u003c/li\u003e\n\u003cli\u003eWerneck MR, Da Silva RJ (2016) Checklist of sea turtles endohelminth in Neotropical region. Helminthologia 53:211\u0026ndash;223. https://doi.org/10.1515/helmin-2016-0045\u003c/li\u003e\n\u003cli\u003eWerneck MR, Hayes PM, Lawton SP (2019). Molecular evidence for resurrection of \u003cem\u003ePlesiochorus elongatus\u003c/em\u003e (Digenea: Gorgoderidae): An urinary bladder parasite of sea turtles. Parasitol Inter 71:180\u0026ndash;185\u003c/li\u003e\n\u003cli\u003eWerneck MR, Nunes C, Jerdy H, Carvalho ECQ (2017) Loggerhead turtle, \u003cem\u003eCaretta caretta\u003c/em\u003e (Linnaeus, 1758) (Testudines, Cheloniidae), as a new host of \u003cem\u003eMonticellius indicum\u003c/em\u003e Mehra, 1939 (Digenea: Spirorchiidae) and associated lesiond to spirorchiid eggs. Helminthologia 54:363\u0026ndash;368. https://doi.org/10.1515/helm-2017-0047\u003c/li\u003e\n\u003cli\u003eWerneck MR, Mastrangelli A, Velloso R, Jerdy H, Carvalho EC (2018) Chronic cystitis associated with \u003cem\u003ePlesiochorus cymbiformis\u003c/em\u003e (Rudolphi, 1819) Looss, 1901 (Digenea: Gorgoderidae) in a loggerhead turtle \u003cem\u003eCaretta caretta\u003c/em\u003e (Linnaeus 1758) (Testudines, Cheloniidae) from Brazil: a case report. J Parasitol 104:334\u0026ndash;336. https://doi.org/10.1645/17-116\u003c/li\u003e\n\u003cli\u003eWerneck, MR, Baldassin P, Mastrangelli A et al (2019). The First Occurrence of \u003cem\u003eEnodiotrema megachondrus\u003c/em\u003e in a Loggerhead Turtle Found on the Coast of Brazil. EC Vet Sci 4:148\u0026ndash;152\u003c/li\u003e\n\u003cli\u003eWork TM (2000) Manual de necropsia de tortugas marinas para bi\u0026oacute;logos en refugios o \u0026aacute;reas remotas. US Geological Survey, National Wildlife Health Center, Hawaii Field Station, Honolulu, Hawaii\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table 1","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":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"loggerhead turtle, leatherback turtle, digenea, nematoda, Argentina","lastPublishedDoi":"10.21203/rs.3.rs-4600556/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4600556/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eParasite studies can provide insights into important aspects of host ecology, which can be particularly important for species of conservation concern. This research focuses on the parasite diversity of two sea turtle species \u0026mdash;the loggerhead \u003cem\u003eCaretta caretta\u003c/em\u003e and leatherback \u003cem\u003eDermochelys coriacea\u003c/em\u003e sea turtles\u0026mdash; in the temperate Southwest Atlantic, a region and species relatively understudied. Over a 15-year period (2008\u0026ndash;2023), 30 sea turtles were sampled from the northern coast of Argentina. Through morphological and molecular tools, we identified five parasite species (the digeneans \u003cem\u003ePyelosomum renicapite\u003c/em\u003e and \u003cem\u003eP. longiusculus\u003c/em\u003e, the nematodes \u003cem\u003eKathlania leptura\u003c/em\u003e and \u003cem\u003eSulcascaris sulcata\u003c/em\u003e and the leech \u003cem\u003eOzobranchus margoi\u003c/em\u003e) in loggerheads; and two digeneans (\u003cem\u003eP. renicapite\u003c/em\u003e and \u003cem\u003eO. amphiorchis\u003c/em\u003e) in leatherbacks. All species constitute the first report of the parasite in Argentina, and \u003cem\u003eO. amphiorchis\u003c/em\u003e represents a new host-parasite association for leatherbacks. Comparative biogeographic analysis using the Regional Management Unit framework revealed that parasites could reveal connectivity between RMUs, though there are several information gaps. Increasing parasite studies can help understand sea turtle feeding ecology, ontogenetic shift and health status, and thus enhance conservation strategies for sea turtles globally.\u003c/p\u003e","manuscriptTitle":"Parasite diversity in sea turtles of the temperate SW Atlantic: a bridge between systematics and ecology","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-09 06:39:34","doi":"10.21203/rs.3.rs-4600556/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4a07abc7-0bdf-4f67-91ff-d7afb860b21c","owner":[],"postedDate":"July 9th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-08-15T12:50:06+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-09 06:39:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4600556","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4600556","identity":"rs-4600556","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}