“Reviving museum oddities: rehydrating Trematodes curiosities!” A successful method for rehydrating dried museum specimens for a revision of the genus Octangium (Trematoda), parasites of green sea turtle Chelonia mydas

“Reviving museum oddities: rehydrating Trematodes curiosities!” A successful method for rehydrating dried museum specimens for a revision of the genus Octangium (Trematoda), parasites of green sea turtle Chelonia mydas | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article “Reviving museum oddities: rehydrating Trematodes curiosities!” A successful method for rehydrating dried museum specimens for a revision of the genus Octangium (Trematoda), parasites of green sea turtle Chelonia mydas Chahinez Bouguerche This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5018739/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Octangium Looss, 1902 is a taxonomically challenging genus of microscaphidiid trematodes, with members harmful at the adult stage to their reptile hosts, the turtles. In Arthur Loss’s collection preserved at the Swedish Museum of Natural History, we found mounted slides of O. sagitta (Looss, 1899) and of O. hasta Looss, 1902, and vials containing Octangium spp. preserved in ethanol from a host and locality matching those listed in Looss (1899), suggesting that this is the part of type material. Unfortunately, several specimens were dried. We attempted herein to rehydrate them, make whole stained mounts, and investigate the material. Additionally, we examined several specimens of O. sagitta and O. hasta from the Invertebrate collections at the SMNH and provided illustrated redescriptions. In light of the available data, also discuss records of O. sagitta , O. hasta , and previous species synonymized with O. sagitta and provide a key for the identification of Octangium spp. We herein reinstate Octangium takanoi Kobayashi, 1921 and O. hasta , and amend Octangium based on a re-examination of adult specimens of the type material of O. sagitta [type species] and of O. hasta , infecting the intestine of the green sea turtle Chelonia mydas . We demonstrate that O. takanoi differs from O. sagitta by being twice smaller, by the shape of the oral sucker (rectangular vs . rounded), and especially by the extent of vitellaria, with their anterior end situated at the level of the anterior margin of the testes in O. takanoi , while they extend to the intestinal bifurcation in O. sagitta . Additionally, they can be easily distinguished by more anterior placing of the testes in O. takanoi . Similarly, O. hasta can be easily distinguished from O. sagitta by being significantly smaller in all body measurements. More importantly, O. sagitta and O. hasta can be easily distinguished by the shape of the oral sucker. We refute thus the synonymies between O. sagitta and the two species O. takanoi and O. hasta , and we reinstate the two latter species as valid species. We summarized and mapped the distribution of current valid species of the genus Octangium . Parasitology Octangium Chelonia mydas Arthur Looss Collection Naturhistoriska riksmuseet Egypt Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Natural History museums worldwide, in addition to housing billions of relevant specimens offering an exceptional potential parasitological dataset for taxonomical studies and various other purposes (Wood & Vanhove, 2023), play a crucial role as a “biodiversity” resource, not only for taxonomists but also for scientists who are dependent on accurate information that transcends specific disciplines. Additionally, as global ecosystems undergo rapid transformation, there is a significant risk of losing biodiversity information. This includes insights into the impacts of accelerated ecological change, which in turn affect human health, the sustainability of food resources, conservation efforts, and the integrity of natural systems (Hoberg et al., 2009). Moreover, collections can be considered historical and environmental benchmarks, allowing us to evaluate shifts in faunal structure. An applied aspect of this is the monitoring of invasive species and emerging diseases resulting from processes such as global climate warming, as well as other human-induced and natural phenomena. In the field of parasitology, it is not uncommon to encounter perplexity regarding taxonomy, the host, and geographic ranges of species. To address these challenges, natural history collections play a key role as they include invaluable type series and vouchers documenting associations across different temporal and spatial scales. They form thus the cornerstone of systematic research by establishing an empirical record that enhances our comprehension of the parasites as part of the biosphere. Moreover, collections are increasingly vital for the advancement of biodiversity informatics, consolidating knowledge on the identity, geographic distribution, ecology, phylogeny, population structure, and historical context of these pathogens’ diversity (Hoberg et al., 2009). Systematics and specimens-based collections are the foundation of an important part of what has been accomplished in parasitology and have resolved a substantial number of real-world problems in human and animal health (Brooks & Hoberg, 2000). Collections can serve as invaluable resources for public health responders seeking to identify the origins and distribution of disease agents. For example, remarkable success has been achieved in protecting human populations from Guinea Worm (Nematoda) once all its developmental stages and host species were sampled, preserved, documented, and analyzed. Moreover, understanding the pathways of tropical diseases like elephantiasis (caused by a Nematode), and schistosomiasis (caused by a Trematode) through various hosts requires the creation and examination of populations of potential host and vector species, both wild and domesticated. Hence, access to collections and the insights gleaned from their analyses will be crucial in comprehending and disrupting the cycles of disease transmission involving multiple species (DiEuliis et al., 2016). The Swedish Museum of Natural History (SMNH) houses a large collection of parasitic invertebrates, including part of the collections of the eminent parasitologist Professor Arthur Looss (Kuzmina & Holovachov, 2023). This collection includes several slides that are type material, and vials containing trematodes preserved in ethanol, along with several publication-ready and original line drawings (Bouguerche et al., 2023) along with notes on host and locality ( Fig. 1 . A-C) . During an ongoing investigation on the systematics of Trematodes at the SMNH collections, we found vials containing Octangium spp. preserved in ethanol from a host and locality matching those listed in Looss (1899) suggesting that this is the part of type material used by Looss in his study. Unfortunately, several specimens were dried out ( Fig. 1 . D, E). Some of the line drawings of parasitic Trematodes that we had, matched the plates given in Looss’s work on systematics and nomenclature of trematodes from sea turtles (Looss, 1902) ( Fig. 2 ) indicating that this is part of the type material. Given their host, this collection of parasites of turtles certainly warrants more attention. Sea turtles confront a multitude of threats, including pollution, habitat degradation, the impacts of climate change, interactions with fisheries, and ingestion of marine debris (Duncan et al., 2019). Moreover, they experience intussusception, a condition where a section of the gastrointestinal tract (known as the intussusceptum) invaginates into the lumen of an adjacent portion, termed the intussuscipiens (MacPhail, 2002) resulting in partial or total obstruction of the gastrointestinal tract (Levit & Bauer, 1992). Interestingly, the existence of parasites is frequently regarded as a predisposing factor for intussusception (see (Duncan et al., 2019). Moreover, Duncan et al. (2019) demonstrated that parasitic infestation by Octangium spp. in sea turtles can root intussusception, subsequently leading to the death of the host turtle. Timely diagnosis is crucial for achieving a favorable prognosis and successful rehabilitation of the host and can only be preceded by an acute identification of the causal Trematode. Thus, we attempted to rehydrate the Trematodes Octangium sp. found in the SMNH, make whole stained mounts, and investigate the material. Additionally, we examined several specimens of O. sagitta and O. hasta from the Invertebrate collections at the SMNH and provided detailed illustrated redescriptions. We also discuss records of O. sagitta , O. hasta , and previous species synonymized with O. sagitta and provide a key for the identification of Octangium spp. 2. Material and methods 2.1. Rehydration of dried specimens The current study is based solely on A. Looss’s specimens and archival documents preserved in the archives and general-type collections of the Department of Zoology, Swedish Museum of Natural History. Several Trematodes, with notes on the host, locality, and microhabitat in the host were dried out. For the rehydration of dried brittle microscaphidiids from A. Looss’s collection, we followed the protocol of Van Cleave & Ross (1947) using trisodium phosphate to soften specimens prior to staining. Hard, brittle, and unyielding dry Trematodes were passed down the grades of alcohol to water and were then placed in a solution of approximately 0,25 percent of trisodium phosphate in distilled water until softened. Specimens were kept in the trisodium phosphate solution (T-Ph-S) for several hours or even days, from four hours to two weeks. No warming oven was used to attain the proper degree of softness and pliability. Treated specimens in T-Ph-S were kept under observation until obtaining the desired degree of softness and translucency. One specimen was treated separately in a petri dish under a dissecting microscope, to check the progress of the treatment. Treated specimens are kept in the solution until turning from excessive hard dark brownish specimens to translucid soft specimens. When the desired degree of softness and translucency has been reached, the treated specimens are removed from the T-Ph-S to distilled water to check the action. When softened, the treated thus treated are washed several times in distilled water, then stored in 70 ethanol. 2.2. Staining and slides mounting Whole-mounts for morphological analysis were stained with acetocarmine for 10 minutes, dehydrated in a graded ethanol series (70, 96. 100. For 20 minutes each), cleared carefully in clove oil, and mounted in Canada balsam. Drawings were made through a Nikon Eclipse i80 microscope with DIC (differential interference contrast) and a drawing tube. Drawings were scanned and redrawn on a computer with Adobe Illustrator 2023. Measurements of whole-mounts are in micrometres and indicated as the range followed by the number of measurements in parentheses. The maximum width was taken slightly behind the middle of the body following Looss (1899). The following abbreviation is used: SMNH, Swedish Museum of Natural History, Stockholm, Sweden. 2.3. Examination of comparative material The collection also includes several total mounts and sections, prepared as described in respective original descriptions of Octangium spp (Looss, 1899, 1901, 1902). Additional material examined in this study includes stained mounts of O. sagitta and O. hasta from Looss’s collection found in the Trematodes collection at the SMNH that were examined and studied for comparison. The studied comparative material included four whole-mounts of O. sagitta (15 specimens) ex C. mydas from Cairo and from Alexandria, Egypt, Eastern Mediterranean; 7 sections of O. sagitta ex C. mydas from Cairo, Egypt, Eastern Mediterranean; 7 whole-mounts of O. hasta (51 specimens) from ex C. mydas from Cairo, Egypt, Eastern Mediterranean; 3 sections ex C. mydas from Cairo, Egypt, Eastern Mediterranean. Measurements and drawings are tacking as explained above. Measurements of specimens from the SMNH Trematodes’ collection were provided separately. 3. Results Family Microscaphidiidae Looss, 1900 Genus Octangium Looss, 1902 Octangium sagitta (Looss, 1899) Looss, 1902 Accepted name Octangium sagitta (Looss, 1899) Looss, 1902 Unaccepted name/ Synonyms Microscapha sagitta Looss, 1899 (Superseded combination). Microscaphidium sagitta (Looss, 189) Looss, 1901 (Superseded combination). Octangium hasta Looss, 1902 (Tentative synonymy by Blair (1987) refuted). Octangium takanoi Kobayashi, 1921 (Tentative synonymy by Blair (1987) refuted). Original name Microscapha sagitta Looss, 1899. Type-host : Chelonia mydas (Testudines: Cheloniidae), the green sea turtle (Looss, 1899). Type-locality off Egypt, Eastern Mediterranean (Looss, 1899). Site in host in original description Rectum (Looss, 1899). Additional hosts : Caretta caretta (Cheloniidae), the Loggerhead sea turtle (Marangi et al., 2020). Eretmochelys imbricata (Cheloniidae), the Hawksbill turtle (Dyer et al., 1995) Additional localities Italy, Adriatic Sea and Northern Ionian Sea, Central Mediterranean (Marangi et al., 2020). Florida, USA, Atlantic, Western-Central (Wyneken et al., 2013). Puerto Rico, Atlantic, Western-Central (Dyer et al., 1991; Dyer et al., 1995). Rio De Janeiro, Brazil, Atlantic, Southwest (Cavaco, 2021; Silva, 2020). Gulf of Mexico, USA, Atlantic, Western-Central (Overstreet et al., 2009). Queensland, Australia, Pacific, Western Central (Johnston, 1913; Johnston, 1916) Other reported habitats the large intestine (Cavaco, 2021; Dyer et al., 1991; Looss, 1902; Overstreet et al., 2009). Terminal section of the small intestine) (Looss, 1902; Overstreet et al., 2009). Gastrointestinal tract (Silva, 2020). Intestine (Johnston, 1913). Note that the report of Marangi et al . (2020) was based on faecal examination to detect eggs in a faecal sample and thus the location of adults in the corresponding host is not available. Habitat in the record by Wyneken et al. (2013) and that of Dyer et al. (1995) not available. Specimens deposited : specimens examined for morphological study, whole mounts: rehydrated specimens from A. Looss’s dried specimens’ collection at the SMNH: O. sagitta ex Chelonia mydas from Cairo , Egypt, Eastern Mediterranean, rehydrated, stained and mounted (SMNH type 9690–9715) Material examined for comparison : Whole mounts, from A. Looss’s collection at the SMNH : O. sagitta ex Chelonia mydas from Alexandria, Egypt, Eastern Mediterranean (SMNH 140048) marked as juveniles (see discussion); O. sagitta ex C. mydas from Alexandria, Egypt, Eastern Mediterranean (SMNH 140049); O. sagitta ex C. mydas from Cairo (Abuk), Egypt, Eastern Mediterranean (SMNH 140050, 140051), O. sagitta ex C. mydas from Cairo, Egypt, Eastern Mediterranean (SMNH 140052). Sectioned material, from A. Looss’s collection at the SMNH ex O. sagitta from Chelonia mydas from Egypt, Eastern Mediterranean; 2 undefined sections (SMNH 140053, SMNH 140059), 2 “queer” sections (SMNH 140054140055), 3 sagittal sections (SMNH 140056, SMNH 140058), 3.1. Redescription (Figs. 3 , 4 ) Comparative measurements in Tables 1 , 2 . Body stocky, ending posteriorly with 2 visible caudolateral projections separated by a terminal notch. Tegument thick, smooth. Mouth terminal. Table 1 Hosts and localities of Octangium spp. Rej., rejected synonym. 1 occasionally small intestine. 2 currently taxon inquirendum . Species Synonyms Type-host Microhabitat Type locality Octangium sagitta (Looss, 1899) Microscapha sagitta Looss, 1899 Microscaphidium sagitta (Looss, 1899) Octangium hasta Looss, 1902 Rej. Octangium takanoi Kobayashi, 1921 Rej. Chelone mydas Rectum Egypt, EM (Blair, 1987; Looss, 1899, 1901, 1902) Octangium hasta Looss, 1902 Octangium sagitta Rej. Chelone mydas Large intestine 1 Egypt, EM (Blair, 1987; Looss, 1902) Octangium takanoi Kobayashi, 1921 Octangium sagitta Rej. Chelone mydas Intestine Singapore, WCP (Kobayashi, 1921) Octangium elongatum Chattopadhyaya, 1972 Chelone mydas Large intestine India, EIO (Chattopadhyaya, 1972) Octangium microrchis Chattopadhyaya, 1972 Eretmochelys imbricata Large intestine India, EIO (Chattopadhyaya, 1972) Octangium hyphalum Blair, 1987 Chelone mydas Pseudocaecum Australia, WCP (Blair, 1987) Abbreviations: EIO., Eastern Indian Ocean. EM., Eastern Mediterranean. WCP., Western Central Pacific Table 2 Comparative measurements for Octangium sagitta (Looss, 1899) from the Mediterranean. * Diameter. a Looss (1899) also reported a length of 1000–2000 µm for very young specimens. b exceptionally 8. NA, not available. Habitat Rectum Intestine ED ED ED NA NA Locality Egypt, E. M. - Alexandria, Egypt, E. M. Cairo, Egypt, E. M. Egypt, E. M. Egypt, E. M. Egypt, E. M. Number of specimens 2 adults - 1 adult 13 adults 23 adults 9 14 Reference Looss (1899) Looss (1902) Present study Present study Present study, rehydrated specimens Sey (1977) in (Blair, 1987) Looss’s (1902) type material from NHR collections (Blair, 1987) Body length 7 000 a Up to 10 000 6776 7061 (4231–10250, n = 11) 6711 (1575–7863, n = 21) 6560 (4900–7800) 6970 (4300–10 380) Body width 2 000 Largest 2 000 1922 1916 (1472–2424, n = 11) 1215 (834–1537, n = 21) 2100 (1660–2420) 1980 (1500–2500) Oral sucker length 276 313 (248–360, n = 9) 321 (237–377, n = 23) 350 (290–480) 310 (230–360, n = 13) Oral sucker width 330 * 370 358 432 (337–518, n = 9) 300 (220–361, n = 23) 340 (280–400) 410 (340–520, n = 13) Oesophagus length 1434 1844 (1197–2180, n = 17) 1440 (1210–1660) 1590 (900–2400) Distance anterior end- intestinal bifurcation 1815 1867 (1249–2411, n = 11) 2179 (1422–2576, n = 18) Distance anterior testes- intestinal bifurcation 1145 1112 (417–1773, n = 10) 859 (655–1052, n = 9) 780 (480–1000) 810 (400–1400) Anterior testis length 860 (45 − 1174, n = 12) 648 (426–837, n = 7) 760 (500–870) 870 (450–1140, n = 13) Anterior testis width 663 (186–1068, n = 12) 307 (239–375, n = 7) 690 (410–1020) 660 (210–1150, n = 13) Posterior testis length 1018 885 (471–1243, n = 12) 641 (421–780, n = 7) 750 (590–950) 870 (500–1210, n = 12) Posterior testis width 630 649 (194–1043, n = 12) 307 (227–398, n = 7) 670 (560–870) 740 (230–1220, n = 12) Ovary length 272 373 (250–521, n = 5) 137 (122–170, n = 4) 270 (160–320, n = 7) 280 (130–440, n = 11) Ovary width 203 293 (230–454, n = 5) 154 (115–193, n = 4) 240 (130–310, n = 7) 240 (100–360, n = 12) Number of excretory diverticula 6–7 b Eggs length 80 80 80 77 (70–81, n = 11) 78 (72–86, n = 23) 49 (45–55, n = 23) 79–87 75–85 Eggs width 53 50 54 51 (42–56, n = 11) 56–64 48–60 Abbreviations: NA, not available. E.M., Eastern Mediterranean. SW.A. Southwest Atlantic. Oral suckers small, rounded to elliptical, with a pair of intramural diverticula distally. Oesophagus long, straight, thick-walled, with an anterior thickening of its musculature at posterior level of oral sucker. Oesophagus ending posteriorly with a voluminous muscular bulb, straight or almost so, with distinct muscular bulb at posterior end. Esophageal bulb with a wide visible lumen, surrounded by numerous glandular cells. Intestinal bifurcation anterior to tests. Caeca large, thick-walled, visibly wrinkled in most specimens, ending close posterior end of body. Testes intercaecal in middle third of body, tandem. Anterior testis always posterior to intestinal bifurcation. Seminal vesicle immediately posterior to, elongated, slightly sinuous in some parts, ending anteriorly by a thin ejaculatory duct. Hermaphroditic duct not examined. Genital pore posterior to sucker. Ovary small, always posterior to testes. Oviduct thin, extended by a large uterus. Uterus extending anteriorly and ending by a thin metraterm. Metraterm joining ejaculatory duct close to genital pore. Vitellarium follicular, arranged in two lateral fields and one median field. Lateral vitelline fields not co-existing entirely with caeca, extending from level of intestinal bifurcation, posteriorly before ends of caeca. Median vitelline field extending from posterior level of ovary to posterior ends of caeca. Eggs in operculated. Excretory rosette formed of 5–8 diverticula. Octangium hasta Looss, 1902 Accepted name Octangium hasta Looss, 1902 Unaccepted name/ Synonyms Octangium sagitta (Looss, 1899) Looss, 1902 (Tentative synonymy by Blair (1987) refuted) Original name Octangium hasta Looss, 1902. Type-host : Chelonia mydas (Testudines: Cheloniidae), the green sea turtle (Looss, 1902). Type-locality Cairo, Egypt, Eastern Mediterranean (Looss, 1902). Site in host in original description Large intestine (Looss, 1902). Specimens examined for morphological study : Whole mounts, from A. Looss’s collection at the SMNH: O. hasta ex C. mydas from Alexandria, Egypt, Eastern Mediterranean (SMNH 140048) marked as juveniles (see discussion); O. hasta ex C. mydas from Cairo, Egypt, Eastern Mediterranean (SMNH 140038–140044). Sections, from A. Looss’s collection at the SMNH: O. hasta ex C. mydas from Cairo, Egypt, Eastern Mediterranean (SMNH 140045–140047). 1.1. Redescription (Figs. 5 , 6 ) Measurements in Table 3 . Body elongate, maximum width at level of midbody. Width uniform in main part of the body, narrowing anteriorly and posteriorly. Body ending posteriorly with 2 caudolateral projections) separated by a terminal notch. Tegument thick, smooth. Mouth terminal. Table 3 Comparative measurements for Octangium sagitta (Looss, 1899) from the Pacific. * Diameter. A Looss (1899) also reported a length of 1000–2000 µm for very young specimens. b exceptionally 8. Habitat ED ED ED NA NA Large intestine Gastrointestinal tract Locality Alexandria, Egypt, EM. Cairo, Egypt, EM. Egypt, EM. Queensland, WCP Puerto Rico, WCA Brazil, SWA. Brazil, SWA. Number of specimens 1 adult 13 adults 23 adults 11 15 NA NA Reference Present study Present study Present study, rehydrated specimens (Blair, 1987) Fischthal & Acholonu 1976 (Blair, 1987) Cavaco (2021) (Silva, 2020) Body length 6776 7061 (4231–10250, n = 11) 6711 (1575–7863, n = 21) 8440 (6140–10 800) 5130 (4000–6000) 6000 (4540–7690) 5580–6470 Body width 1922 1916 (1472–2424, n = 11) 1215 (834–1537, n = 21) 2480 (1880–2780) 1350 (1100 − 1540) 1700 (990–2980) 3760–4310 Oral sucker length 276 313 (248–360, n = 9) 321 (237–377, n = 23) 510 (300–630, n = 9) 320 (260–340) 237 (158–351) 510–580 Oral sucker width 358 432 (337–518, n = 9) 300 (220–361, n = 23) 520 (450–590, n = 9) 270 (220–320) 285 (214–377) 530–630 Oesophagus length 1434 1844 (1197–2180, n = 17) 1780 (1320–2400) 1380 (1160– 1520) 923 (490–1269) 1020–1270 Distance anterior end- intestinal bifurcation 1815 1867 (1249–2411, n = 11) 2179 (1422–2576, n = 18) 280–310 Distance anterior testes- intestinal bifurcation 1145 1112 (417–1773, n = 10) 859 (655–1052, n = 9) 960 (740–1400) 500 (320–580) Anterior testis length 860 (45 − 1174, n = 12) 648 (426–837, n = 7) 1030 (650–1430) 450 (280–580) 667 (381–902) 500–610 Anterior testis width 663 (186–1068, n = 12) 307 (239–375, n = 7) 750 (560–1150) 230 (160–340) 666 (383–994) 950–1090 Posterior testis length 1018 885 (471–1243, n = 12) 641 (421–780, n = 7) 1080 (680–1380) 440 (290–530) 628 (468–912) 520–580 Posterior testis width 630 649 (194–1043, n = 12) 307 (227–398, n = 7) 840 (590–1360) 230 (140–350) 489 (284–755) 960–1110 Ovary length 272 373 (250–521, n = 5) 137 (122–170, n = 4) 310 (210–370) 130 (90–180) 206 (146–258) 450–510 Ovary width 203 293 (230–454, n = 5) 154 (115–193, n = 4) 290 (150–380) 70 (60–110) 176 (99–245) 290–320 Number of excretory diverticula Eggs length 80 77 (70–81, n = 11) 78 (72–86, n = 23) 49 (45–55, n = 23) (71–83, n = 12) 67–75 83 (71–92) Eggs width 54 51 (42–56, n = 11) (48–52, n = 12) 39–50 49 (42–57) Abbreviations: NA, not available. E.M., Eastern Mediterranean. WCA., Western-central Atlantic. WCP., Western central pacific. SWA. Southwest Atlantic. Oral sucker somewhat rectangular. Oesophagus long, thick walled, with a wide lumen, ending posteriorly with a distinct oesophageal bulb. Esophageal bulb with a wide lumen, surrounded by numerous glandular cells. Intestinal bifurcation at anterior third. Caeca straight. Testes pre-ovarian, intercaecal in midbody, posterior to intestinal bifurcation, oval, disposed in tandem. Eggs in utero operculated. Seminal vesicle posterior to anterior tests. Ejaculatory duct joining metraterm. Hermaphroditic duct not examined. Genital pore posterior to ventral sucker. Ovary small, ventral, always posterior to testes. Oviduct thin, extended by the uterus. Uterus extending anteriorly and ending by a thin metraterm. Vitellarium arranged as in O. sagitta . Lateral vitelline co-existing partially with caeca, anterior limit of lateral vitelline fields not attending level of intestinal bifurcation, posterior limit before ends of caeca. Median vitelline field extending from posterior level of ovary and not reaching posterior ends of caeca. Vitellarium follicular, arranged in two lateral fields and one median field. Lateral vitelline fields not co-existing entirely with caeca, extending from level of intestinal bifurcation, posteriorly before ends of caeca. Median vitelline field extending from posterior level of ovary to posterior ends of caeca. Eggs in operculated. 4. Discussion 2.1. Looss’s Trematodes collection Arthur Looss died after a long illness on May 4, 1923, at Giessen. Born on May 16, 1861, at Chemnitz, he received his education in his native city and at Lodz in Poland, then at the University of Leipzig where he received the degree of Doctor of Philosophy, his thesis being on the Trematodes (Vaughan, 1924). He was for many years, a professor of parasitology and biology at the School of Medicine in Cairo. He pursued his work until after the outburst of the World War when he retired from his chair and returned to Germany (Vaughan, 1924). Looss dedicated his life to the study of helminthology, not only systematics and nomenclature as he made outstanding inputs to the medical aspect of helminthology. One of the spectacular discoveries of his career, was when he was sent by Leuckart to Egypt to study the transmission of bilharzia, where there he became interested in hookworm and due to an accidental infection of himself that made the discovery of the aptitude of larval worm to enter the skin, then transported to the heart, lungs and intestinal tract (Vaughan, 1924). Certainly, by the finding of the mode of infection Looss also clearly helped determine the way to prevent the disease. Hence, it is only fair to say that Looss not only “made for himself a name as one of the most distinguished of helminthologists” but also “put the world under a debt of gratitude to him”. After his death, his collection was sold to different museum and part of it to the Swedish Museum of Natural history (Kuzmina & Holovachov, 2023). This collection includes numerous slides that are actually type material, and vials comprising ethanol-preserved trematodes, and various publication-ready and original line drawings (Bouguerche et al., 2023) beside notes of records on host and locality. For O. sagitta , some of the line drawings of parasitic Trematodes that we had, matched the plates given in Looss’s work on systematics and nomenclature of trematodes from sea turtles (Looss, 1902) ( Fig. 2 ) indicating that this is part of the type material. Thus, we attempted to rehydrate the Trematodes O. sagitta and we made whole stained mounts that we used to investigate these Trematodes and the systematics of the genus. Hence, these Trematodes even in compromised condition, provided still instrumental data for the systematics of the genus Octangium , aiding in the identification of Octangium spp. Advances in genetic and molecular techniques will certainly also allow to extraction of DNA from degraded specimens, offering insights into evolutionary relationships and the genetic structure of populations. 2.2. Rehydration of dried specimens Van Cleave and Ross (1947) stated that freshly preserved specimens become soft and translucent shortly after, while hard dry specimens soften after several hours or even days. Herein, all the microscaphidiids from A. Looss’s collection were hard, brittle, and unyielding after long preservation and thus required a longer treatment up to four hours in the rehydrating solution. However, smaller Trematodes, such as Lecithocladium excisum (Rudolphi, 1819) (in an upcoming study) required shorter rehydrating time and became softened within 45 minutes at the earliest. Van Cleave and Ross (1947) also mentioned that hard dry specimens might require even days in a warming oven before they attain the proper degree of softness and pliability. However, no warming oven was used to attain the proper degree of softness and pliability. The only difference was examined regarding the time of rehydration. Specimens that were kept for several days in the rehydrating solution tend to clear better in clove oil after the staining. 2.3. Systematics of Octangium spp. Microscaphidiid Trematodes of the genus Octangium Looss, 1902 are typically parasites of the intestine of marine turtles (Cheloniidae), in nearly all tropical and subtropical seas. Members of this genus are readily distinguished by a body with a profound posterior terminal notch, visible between paired caudolateral projections, a simple not recurved excretory vesicle, and the presence of a rosette of diverticula present just proximal to the excretory pore (Blair, 2005). The genus Octangium is in need of systematic revision. Overall, 7 species have been assigned to the genus Octangium (WoRMS, 2023): O. sagitta of which O. hasta , and O. takanoi Kobayashi, 1921, were considered synonyms; and O. hyphalum Blair, 1987, of which O. takanoi Kobayashi sensu Mehrotra (1973) and Tandon and Gupta (1981) was considered a synonym (Blair, 2005). The most recent species are O. elongatum Chattopadhyaya, 1972, from the large intestine of the green sea turtle Chelonia mydas and O. microrchis Chattopadhyaya, 1972 from the hawksbill sea turtle Eretmochelys imbricata from the eastern Indian Ocean, off India, are both currently taxon inquirendum (Blair, 1987). Another Microscaphidiid species from marine turtles assigned previously to this genus is O. travassosi (Ruiz, 1943), first described from the intestine of an unidentified marine turtle referred to as “ Tartaruga marinha (sp.?)” from the southwest Atlantic, off Brazil as Neoctangium travassosi Ruiz, 1943 (Ruiz, 1943), then placed in the genus Octangium when Yamaguti (1958) synonymized Neoctangium with Octangium , first without explanation (Blair, 1987), then justified his decision and wrote “Ruiz (1943) distinguished Neoctangium Ruiz, 1943 from Octangium simply because of the presence of 4 pairs of cephalic [sic] papillae” (Yamaguti, 1971). Blair (1987) refuted the synonymy between the two genera and considered it “unreasonable” as Ruiz (1943) omitted any mention of the excretory system in his description. Moreover, Blair (1987) demonstrated that the arrangement of excretory system in Neoctangium (with an elongate recurved bladder, lacking a rosette of diverticula proximal to the excretory pore, reception of excretory ducts at a single median point proximally; a ventral excretory pore) is highly dissimilar from that of Octangium spp and resurrected Neoctangium based upon. Hence, the genus today remains bispecific, with O. sagitta and O. hyphalum Blair, 1987, first described from the Pseudocaecum and large intestine of also the same host, C. Mydas from the western central pacific, off Queensland (Blair, 1987). In the following section, we discuss previous synonymies proposed within this genus. Two species have been synonymised with the type species O. sagitta . The first is O. takanoi (Blair, 1987). Octangium takanoi was first described from the same host as O. sagitta , off Singapore, Western Central Pacific (Kobayashi, 1921). Blair (1987) synonymised it with O. sagitta based on examining figures of Kobayashi (1921). Even though the eggs of O. takanoi and those of O. sagitta do indeed overlap (despite Kobayashi (1921) distinguishing it from its congeners by eggs size), O. takanoi can be easily distinguished from O. sagitta by being twice smaller (5500 ×1200 vs . 4231–10250 × 1472–2424), by the shape of the oral sucker (rectangular vs . rounded) and especially by the extent of vitellaria, with their anterior end situated at the level of the anterior margin of the testes in O. takanoi ( Fig. 7 A ) , while they extend to the intestinal bifurcation in O. sagitta ( Fig. 7 G, H ) . Additionally, they can be easily distinguished by more anterior placing of the testes in O. takanoi (both testes are in the anterior half in O. takanoi . We refute thus the synonymy between the two species, and we reinstate O. takanoi as a valid species. Octangium takanoi was reported by Mehrotra (1973) in an abstract communicated by N. K. Gupta from India without giving any additional information (Blair, 1987). Subsequently, Tandon and Gupta (1981) provided a redescription and morphometrical data of O. takanoi from the intestine of C. mydas from the Gulf of India, Eastern Indian Ocean. The microscaphidiids reported by Tandon and Gupta (1981) (that we refer to in Table 4 as O. takanoi sensu Tandon and Gupta (1981)) are larger than O. takanoi and have larger eggs. Most importantly, in O. takanoi the vitellarium extends to the anterior margin of the anterior testis while in O. takanoi sensu Tandon and Gupta (1981), the vitellarium extends about the middle of the posterior testis ( Fig. 7 B ) and the two populations can be easily distinguished by the more anterior placement of tests in O. takanoi . Hence, the microscaphidiids reported by Tandon and Gupta (1981) are not O. takanoi . We note that O. takanoi sensu Tandon and Gupta (1981) resembles O. hyphalum , in which the vitellarium’s anterior limit near the point of contact between testes ( Fig. 7 C ) and the measurements of different body parts and of eggs overlap. Hence, as previously suggested by Blair (1987), the two populations are highly likely conspecific. Table 4 Comparative measurements for Octangium hasta Looss, 1902. * Diameter. 1 Host Chelonia mydas Chelonia mydas Chelonia mydas Chelonia mydas Habitat Large intestine ED ED ? Locality Egypt, EM. Cairo, Egypt, EM. Cairo, Egypt, EM. Cairo, Egypt, EM. Number of specimens NA 30 adults 12 juveniles 34 Reference (Looss, 1902). Present study Present study Looss’s (1902) type material from NHR collections (Blair, 1987) Body length 3–3300, max 4000 2953 (2148–3950, n = 30) 2187 (1569–2942, n = 12) 2940 (2150–3880) Body width Up to 900 789 (595–1128, n = 30) 577 (412–754, n = 12) 830 (630–1150) Oral sucker length 187 (124–251, n = 27) 162 (135–198, n = 12) 190 (150–240) Oral sucker width 199 (117–261, n = 27) 158 (128–195, n = 12) 200 (150–270) Oesophagus length 758 (509–1049, n = 30) 595 (445–717, n = 12) 770 (540–1000) Distance anterior end- Intestinal bifurcation 977 (709–1278, n = 30) 758 (555–904, n = 12) Distance anterior testes- intestinal bifurcation 439 (302–579, n = 30) 344 (205–502, n = 11) 370 (200–490) Anterior testis length 236 (147–470, n = 28) 109 (35–227, n = 11) 230 (130–380) Anterior testis width 157 (107–281, n = 28) 73 (20–154, n = 11) 200 (110–380) Posterior testis length 246 (129–500, n = 26) 115 (32–223, n = 11) 230 (110–380) Posterior testis width 156 (99–270, n = 26) 71 (24–145, n = 11) 190 (100–370) Ovary length 134 (94–203, n = 8) 72 (66–78, n = 2) 100 (60–150) Ovary width 105 (67–249, n = 8 57 (56–57, n = 2) 80 (60–110) Number of excretory diverticula Eggs length 84 78 (68–85, n = 25) 71–87 Eggs width 50 52 (41–62, n = 25) 48–58 Abbreviations: NA, not available. E.M., Eastern Mediterranean. Table 5 Comparative measurements for Octangium spp. * Diameter. 1 Species Octangium sagitta O. hasta O. hyphalum Blair, 1987 O. takanoi Kobayashi, 1921 O. takanoi sensu Tandon and Gupta (1981) Host Chelonia mydas Habitat ED ED Pseudocaecum, large intestine Intestine Intestine Locality Cairo, Egypt, E. M. Cairo, Egypt, EM. Queensland Singapore, Western Central Pacific India, Eastern Indian Ocean Number of specimens 13 adults 30 adults 19 NA NA Reference Present study Present study (Blair, 1987) (Kobayashi, 1921) Tandon and Gupta (1981) Body length 7061 (4231–10250) 2953 (2148–3950) 3040–6520 (4580) 5500 5160–7800 Body width 1916 (1472–2424) 789 (595–1128) 1100–2500 (1710) 1200 1240–1980 Oral sucker length 313 (248–360) 187 (124–251) 220–460 (320) 290–400 Oral sucker width 432 (337–518) 199 (117–261) 300–530 (380) 170–340 Oesophagus length 758 (509–1049) 620–1280 (910) 1420–2060 Number of excretory diverticula 6 Distance anterior end- Intestinal bifurcation 1867 (1249–2411) 977 (709–1278) Distance anterior testes- intestinal bifurcation 1112 (417–1773) 439 (302–579) 80–280 (170) Anterior testis length 860 (45 − 1174) 236 (147–470) 300–940 (540) 400–890 Anterior testis width 663 (186–1068) 157 (107–281) 280–1040 (530) 360–990 Posterior testis length 885 (471–1243) 246 (129–500) 280–1030 (540) 410–870 Posterior testis width 649 (194–1043) 156 (99–270) 240–980 (510) 330–990 Ovary length 373 (250–521) 134 (94–203) 120–480 (240) 150–230 Ovary width 293 (230–454) 105 (67–249) 110–300 (200) 90–250 Eggs length 77 (70–81) 78 (68–85) 67–79 70–75 58–78 Eggs width 51 (42–56) 52 (41–62) 44–50 45 44–53 Another current ambiguity within this genus is related to the type species of the genus, O. sagitta with the related synonyms. Octangium sagitta was first described by Looss (1899) as Microscapha sagitta Looss, 1899, from the rectum of the Green sea turtle C. mydas . In his subsequent comments on the names previously suggested for some “Distomid” genera, Looss (1900) renamed the corresponding genus Microscapha Looss, 1899, Microscaphidium Looss, 1900 before subsequently placing Microscapha sagitta in the latest genus (Looss, 1901). It was at last placed in the genus Octangium Looss, 1902 (Looss, 1902). Blair (1987) synonymised O. sagitta with O. hasta , first described from the large intestine of the same host, C. mydas from the Eastern Mediterranean, off Egypt (Looss, 1902). In the current study, we compared O. sagitta to O. hasta , and the two species can be easily distinguished by measurements, with O. hasta being significantly smaller in all body measurements (see also ( Fig. 8 ) , where all adult specimens were drawn to the same scale ) . More importantly, O. sagitta and O. hasta can be easily distinguished by the shape of the oral sucker ( Fig. 7 G, H vs . D-F) . Thus, we reinstate O. hasta as a valid species. We summarize the distribution of current valid species in Fig. 9 and we provide a diagnostic key to species of the genus. Key to Species Lateral vitelline fields with anterior limit close to fork of caeca, oral sucker rounded.................... O. sagitta Lateral vitelline fields with anterior limit close to fork of caeca, oral sucker rectangular................. O. hasta Lateral vitelline fields with anterior limit beyond point of contact between testes ....................... O. takanoi Lateral vitelline fields with anterior limit near point of contact between testes ........................ O. hyphalum Declarations Acknowledgments We thank Dr. Christopher Blanar, Professor of Biology from the Nova Southeastern University. U.S.A. and Dr. Whitney Preisser, Professor at Kennesaw State University, Georgia (KSU) for suggesting the methods to rehydrate specimens. Special thanks to Adrian Lenninger for kindly generating accession numbers. This research was funded by the Swedish Taxonomy Initiative, Artdatabanken, Swedish University of Agricultural Sciences within the scope of the project “Taxonomy and systematics of digenetic trematodes parasitising fishes of Sweden” (dha 2019.4.3–48). References Blair, D. (1987). A revision of the subfamily Octangiinae (Platyhelminthes, Digenea, Microscaphidiidae) parasitic in marine turtles (Reptilia, Chelonia).. Australian Journal of Zoology , 35 (1), 75–92. https://doi.org/https://doi.org/10.1071/zo9870075 Blair, D. (2005). Family Microscaphidiidae Looss, 1900. In Keys to the Trematoda: Volume 2 (pp. 193–211). CABI Publishing Wallingford UK. Bouguerche, C., Huston, D. C., Cribb, T. H., Karlsbakk, E., Ahmed, M., & Holovachov, O. (2023). Hidden in the fog: morphological and molecular characterisation of D erogenes varicus sensu stricto (Trematoda, Derogenidae) from Sweden and Norway, and redescription of two poorly known Derogenes species. Parasite , 30 , 35. https://doi.org/10.1051/parasite/2023030 (Caché dans le brouillard : caractérisation morphologique et moléculaire de Derogenes varicus sensu stricto (Trematoda, Derogenidae) de Suède et de Norvège, et redescription de deux espèces de Derogenes peu connues.) Brooks, D. R., & Hoberg, E. P. (2000). Triage for the biosphere: the need and rationale for taxonomic inventories and phylogenetic studies of parasites. Comparative Parasitology , 67 (1), 1–25. Cavaco, B. M. M. (2021). Análise parasitológica de tratos digestivos de tartarugas verdes juvenis (Chelonia mydas) provenientes do estado do Rio de Janeiro, Brasil Universidade de Lisboa, Faculdade de Medicina Veterinária]. Chattopadhyaya, D. R. (1972). Studies on the trematode parasites of reptiles found in India. 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Some digeneans (Trematoda) of the Atlantic hawksbill turtle Eretmochelys imbricata imbricata (Testudines: Cheloniidae) from Puerto Rico. Journal of Helminthological Society of Washington , 62 , 13–17. Hoberg, E. P., Pilitt, P. A., & Galbreath, K. E. (2009). Why museums matter: a tale of pinworms (Oxyuroidea: Heteroxynematidae) among pikas ( Ochotona princeps and O. collaris ) in the American West. Journal of Parasitology , 95 , 490–501. Johnston, S. (1913). Memoirs: On some Queensland trematodes, with anatomical observations and descriptions of new species and genera. Journal of Cell Science , 2 (235), 361–400. Johnston, T. H. T. H. (1916). A census of the endoparasites recorded as occurring in Queensland, arranged under their hosts. Proceedings of the Royal Society of Queensland , 28 , 31–79. Kobayashi, H. (1921). On some digenetic trematodes in Japan. Parasitology , 12 , 380–410. Kuzmina, T., & Holovachov, O. (2023). Equine Strongylidae and other parasitic nematodes described by Arthur Looss during 1895–1911 in the collections of the Swedish Museum of Natural History. Zootaxa , 5227 (2), 151–193. Levit, L., & Bauer, M. (1992). Intussusception in dogs and cats: A review of thirty-six cases. Canadian Veterinary Journal, Canadá , 33 (10), 660–664. Looss, A. (1899). Weitere Beiträge zur Kenntniss der Trematoden-Fauna Aegyptens, zugleich Versuch einer natürliden Gliederung des Genus Distomum Retzius. Zoologische Jahrbücher Abteilung für Systematik, Geographie und Biologie der Tiere , 12 , 521–784. Looss, A. (1900). Nachträgliche Bemerkungen zu den Namen der von mir vorgeschlagenen Distomidengattungen. Zoologischer Anzeiger , 23 , 601–608. Looss, A. (1901). Ueber Trematoden aus Seeschildkröten der egyptischen Küsten. (Notizen zur Helminthologie Egyptens. 4). Centralblatt. Bakteriol. 1 Abt , 30 , 555–569, 618–625. Looss, A. (1902). Über neue und bekannte Trematoden aus Seeschildröten. Nebst Erörterungen zur Systematik un Nomenclatur. Zoologische Jahrbücher. Abteilung für Systematik Okologie und Geographie der Tiere. , 16 , 411–894. MacPhail, C. (2002). Gastrointestinal obstruction. Clinical Techniques in Small Animal Practice , 17 (4), 178–183. Marangi, M., Carlino, P., Profico, C., Olivieri, V., Totaro, G., Furii, G., Marzano, G., & Papini, R. A. (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. International Journal for Parasitology: Parasites and Wildlife , 11 , 207–212. Overstreet, R. M., Cook, J. O., & Heard, R. W. (2009). Trematoda (platyhelminthes) of the Gulf of Mexico. Gulf of Mexico—origins, waters, and biota , 1 , 419–486. Ruiz, J. M. (1943). Neoctangium travassosi gen. n., sp, n. (Trematoda : Paramphistomoidea) parasito do quelBnio marinho. Chave dos gineros da familia Microscaphidiidae Travassos, 1922. Memórias do Instituto Butantan (Sao Paulo) 17 , 35–45. Silva, C. G. d. (2020). Identificação da fauna parasitária de tartarugas-marinhas encalhadas ao norte do sudoeste atlântico, brasil. Tandon, V., & Gupta, N. (1981). On Deuterobaris intestinalis Mehrotra, 1973 and Octangium takanoi Kobayashi, 1921 (Trematoda: Microscaphidiidae) from a marine turtle in India. Proceedings: Animal Sciences , 90 , 553–560. Van Cleave, H. J., & Ross, J. A. (1947). Use of trisodium phosphate in microscopical technic. Science , 106 (2748), 194–194. Vaughan, H. F. (1924). "The death of Arthur Looss". American Journal of Public Health , 13 ((8)), 659. doi:610.2105/AJPH.2113.2108.2659. Wood, C. L., & Vanhove, M. P. (2023). Is the world wormier than it used to be? We'll never know without natural history collections. Journal of Animal Ecology , 92 (2), 250–262. WoRMS. (2023). Octangium Looss, 1902. Accessed at: https://marinespecies.org/aphia.php?p=taxdetails&id=725391 on 2023-09-19 . Wyneken, J., Lohmann, K. J., & Musick, J. A. (2013). The Biology of Sea Turtles, Volume III . CRC Press. https://books.google.se/books?id=Xf_RBQAAQBAJ Yamaguti, S. (1958). 'Systema Helminthum. 1. The Digenetic Trematodes of Vertebrates.' Vol. 1. (Interscience Publishers, New York.). Yamaguti, S. (1971). Synopsis of the digenetic trematodes of vertebrates. Vol. 1, 1074 pp, Vol. II, 349 plates Keigaku. Additional Declarations The authors declare no competing interests. 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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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5018739","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":348439383,"identity":"197d1d48-ac3a-40d3-b608-9b508dc5c100","order_by":0,"name":"Chahinez Bouguerche","email":"data:image/png;base64,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","orcid":"","institution":"Naturhistoriska riksmuseet","correspondingAuthor":true,"prefix":"","firstName":"Chahinez","middleName":"","lastName":"Bouguerche","suffix":""}],"badges":[],"createdAt":"2024-09-02 13:33:04","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-5018739/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5018739/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":63993570,"identity":"c64f404a-3a51-4f0c-a3a1-6e927bf5b643","added_by":"auto","created_at":"2024-09-04 16:00:17","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":74540039,"visible":true,"origin":"","legend":"\u003cp\u003eMaterial of \u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) ex \u003cem\u003eChelonia mydas\u003c/em\u003e from A. Looss’s collection including notes and specimens. \u003cstrong\u003eA-C,\u003c/strong\u003e Archival notes indicating host, locality and collection dates for \u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) ex \u003cem\u003eChelonia mydas\u003c/em\u003e from A. Looss’s collection. Note the mention “type” on \u003cstrong\u003eA\u003c/strong\u003e and \u003cstrong\u003eB\u003c/strong\u003e. \u003cstrong\u003eD, E,\u003c/strong\u003e dried specimens of \u003cem\u003eOctangium sagitta\u003c/em\u003e ex \u003cem\u003eChelonia mydas\u003c/em\u003e. \u003cstrong\u003eF,\u003c/strong\u003eRehydrated specimens of \u003cem\u003eOctangium sagitta\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/d84999be56f9cf6fe48262bb.png"},{"id":63994873,"identity":"5d8045ad-1380-45b4-8db4-fa5444a8f8a0","added_by":"auto","created_at":"2024-09-04 16:16:16","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":125765,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) ex \u003cem\u003eChelonia mydas\u003c/em\u003e. Original publication-ready drawing of \u003cem\u003eO. sagitta\u003c/em\u003e published as figs. 122-127 and 133, and of \u003cem\u003eOctangium hasta \u003c/em\u003eLooss, 1902 as figs. 128-132 in Plate 29, Looss (1902). Red arrows indicates figures related to \u003cem\u003eO. sagitta\u003c/em\u003e. Blue arrows indicates figures related to \u003cem\u003eO. hasta\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/ca6e468c7232491bf82e6ade.png"},{"id":63993569,"identity":"7fa2cdc8-b755-42b9-b008-213a5faa27b3","added_by":"auto","created_at":"2024-09-04 16:00:16","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":144568,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOctangium sagitta \u003c/em\u003e(Looss, 1899) ex \u003cem\u003eChelonia mydas\u003c/em\u003e based on A. Looss’s original drawings.\u003c/p\u003e\n\u003cp\u003eA, Young individual shaken in sublimate and in glycerin brightened; overall view of the reticulated part of the excretory bladder.\u003c/p\u003e\n\u003cp\u003eAbbreviations:\u003c/p\u003e\n\u003cp\u003e\u003cem\u003edl\u003c/em\u003e and \u003cem\u003edr\u003c/em\u003e the left and right dorsal, \u003cem\u003evl\u003c/em\u003e and \u003cem\u003evr\u003c/em\u003e the left and right ventral, \u003cem\u003edll\u003c/em\u003e and \u003cem\u003edlr\u003c/em\u003e the left and right dorsolateral, \u003cem\u003evll\u003c/em\u003e and \u003cem\u003evlr\u003c/em\u003e the left and right ventrolateral longitudinal trunk of the network; \u003cem\u003etll\u003c/em\u003e and \u003cem\u003etlr\u003c/em\u003e fork points of the previously simple right and left lateral trunks; \u003cem\u003etvr\u003c/em\u003e right-sided division point of the ventral and lateral longitudinal trunk.\u003cem\u003e*\u003c/em\u003e Point of departure of communication between the dorsal and ventral parts of the vascular network.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eB,\u003c/strong\u003e Structure of the oral sucker according to an individual as shown in Fig. 122, drawn in outlines.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC, \u003c/strong\u003eCross-section through the oral sucker of an adult specimen at the level of the base of the 4 lips of the anterior margin.\u003c/p\u003e\n\u003cp\u003eAbbreviations:\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eaem\u003c/em\u003e outer aequatorial fibers. \u003cem\u003esw\u003c/em\u003e Beginning of the outer and inner. \u003cem\u003ems\u003c/em\u003e the first, from the sides of the oral sucker lumen after the muscle bundles extending to the dorsal and ventral oral sucker wall. \u003cem\u003em\u003c/em\u003e beginning of the lateral longitudinal muscle bundle located in the outer sheath.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eD\u003c/strong\u003e, Section through the same oral sucker in approximately its middle. Outer and inner coats clearly separated from each other; the composition of the septum made up of two half septums is clearly visible.\u003c/p\u003e\n\u003cp\u003eAbbreviations as in the previous figure; \u003cem\u003eem\u003c/em\u003e external, \u003cem\u003eimm\u003c/em\u003e the strongly entrapped inside meridional fibers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eE,\u003c/strong\u003e Frontal section through the pharynx.\u003c/p\u003e\n\u003cp\u003eAbbreviations:\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ea\u003c/em\u003e\u003csup\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sup\u003e anterior, \u003cem\u003ea\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e middle,\u003cem\u003ev\u003c/em\u003e posterior expansion of the lumen; the front wall of the latter seems to be able to act as a closure device. \u003cem\u003ermoe\u003c/em\u003e simple ring fiber layer, in the longitudinal fiber layer of the esophagus; \u003cem\u003erm\u003c/em\u003e thickened annular musculature of the pharynx; \u003cem\u003erms\u003c/em\u003e simple ring-fiber layer of the limbs of the esophagus (of the oesophagus abomination).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eF,\u003c/strong\u003e Part of a cross-section through the front body on the height of the nerve ring (\u003cem\u003ene\u003c/em\u003e) with oesophagus \u003cem\u003eOe\u003c/em\u003e and terminal parts of the Genital ducts.\u003c/p\u003e\n\u003cp\u003eAbbreviations:\u003c/p\u003e\n\u003cp\u003e\u003cem\u003erm\u003c/em\u003e ring, \u003cem\u003eIm\u003c/em\u003e longitudinal fibers, \u003cem\u003ebx\u003c/em\u003e companion cells of the Oesophagus; \u003cem\u003edr\u003c/em\u003e dorsoventral parenchymal muscles. Pars prostatica, as well as the uterus with some ungiving accompanying cells from a very thin parenchymal lamella \u003cem\u003ebs\u003c/em\u003e surrounded; \u003cem\u003eEx\u003c/em\u003e cross section of connecting channels the dorsal and ventral network of the excretory bladder.\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/afbddcacf678d30db586a495.png"},{"id":63993562,"identity":"741e32ab-abad-4613-9cfa-f67b3461b87c","added_by":"auto","created_at":"2024-09-04 16:00:16","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":103209,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOctangium sagitta \u003c/em\u003e(Looss, 1899) ex \u003cem\u003eChelonia mydas\u003c/em\u003e. A, whole body of a specimen from A. Looss slides collection at the SMNH Invertebrates collection, mounted by A. Looss (SMNH-140049). B, whole body of a rehydrated specimen (SMNH Type -9694)\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/e6d7df659f989a0bc7a7a2f6.png"},{"id":63993563,"identity":"b12211a4-6c4c-419d-a63e-dc4917fe6db4","added_by":"auto","created_at":"2024-09-04 16:00:16","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":158412,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOctangium hasta \u003c/em\u003eLooss, 1902 ex \u003cem\u003eChelonia mydas\u003c/em\u003e based on A. Looss’s original drawings.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eA, \u003c/strong\u003eAdult individual, lightened in glycerin; ventral view. To visualize the pharynx, the uterus and seminal vesicle, which are otherwise located together with the esophagus and pharynx in the sagittal plane of the body, are drawn slightly bent out to the side.\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage5.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/a8545f11c851a32fda2fe682.png"},{"id":63995308,"identity":"56f1debc-42ac-463f-a53b-4548b4daca58","added_by":"auto","created_at":"2024-09-04 16:24:16","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":145838,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOctangium hasta \u003c/em\u003eLooss, 1902 ex \u003cem\u003eChelonia mydas\u003c/em\u003e based on A. Looss’s original drawings.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eA, \u003c/strong\u003eAdult individual, lightened in glycerin; ventral view. To visualize the pharynx, the uterus and seminal vesicle, which are otherwise located together with the esophagus and pharynx in the sagittal plane of the body, are drawn slightly bent out to the side.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eB,\u003c/strong\u003e Young individual, as shown in \u003cstrong\u003eFig. 2 A\u003c/strong\u003e; Total scheme of the reticular part of the excretory bladder. The leading, smaller meshes of the network are noticeably less numerous as in \u003cem\u003eOctangium sagitta\u003c/em\u003e \u003cstrong\u003e(Fig. 2 A)\u003c/strong\u003e. Letter designations as in \u003cstrong\u003eFig. 2 A\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC,\u003c/strong\u003e Oral sucker, for comparison with that of the \u003cem\u003eOctangium sagitta\u003c/em\u003e, drawn in the same way as in \u003cstrong\u003eFig. 2 B\u003c/strong\u003e. Lips of the front edge not retracted.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eD,\u003c/strong\u003e Surface view of the pharynx from an adult animal. Conditions as shown in 2.E; \u003cem\u003esoe\u003c/em\u003e the legs of the esophagus, at the ends of which the intestinal legs attach.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eE,\u003c/strong\u003e Sagittal section through the terminal parts of the genital ducts; \u003cem\u003ee,e\u003c/em\u003ethe two constrictions of the wall of the pars prostatica; \u003cem\u003eov\u003c/em\u003e a mature egg located in the uterus.\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage6.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/f69e6427d9b629ccd26a0a6d.png"},{"id":63995936,"identity":"dc92b05e-18f3-46e1-8abb-4845291b06da","added_by":"auto","created_at":"2024-09-04 16:32:16","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":141109,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOctangium hasta \u003c/em\u003eLooss, 1902 ex \u003cem\u003eChelonia mydas\u003c/em\u003e. Whole body of specimenS from A. Looss slides collection at the SMNH Invertebrates collection, mounted by A. Looss (SMNH-140042).\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage7.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/b69abef1e07a0ef28ca7ae1f.png"},{"id":63993567,"identity":"70baa98f-e0b3-45f0-9a92-66a303848c95","added_by":"auto","created_at":"2024-09-04 16:00:16","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":88529,"visible":true,"origin":"","legend":"\u003cp\u003eGeneral body shapes of \u003cem\u003eOctangium hasta \u003c/em\u003eLooss, 1902 ex \u003cem\u003eChelonia mydas\u003c/em\u003e (A-F) and\u003cem\u003eOctangium sagitta \u003c/em\u003e(Looss, 1899) ex \u003cem\u003eChelonia mydas\u003c/em\u003e (G-I) . Oral suckers are indicated in red. Testes are indicated in yellow. Vitelline follicles are indicated in green. Note that all adult specimens were drawn to the same scale.\u003c/p\u003e\n\u003cp\u003eA, SMNH-140038. B, SMNH-140039. C, SMNH-140041. D, SMNH-140040. E, SMNH-140043. F, SMNH-140044. G, 140049. H, 140052. I, 140050\u003c/p\u003e","description":"","filename":"Bouguerche2024FiguresPage8.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/c992a40af7750f5e336badee.png"},{"id":63994314,"identity":"a2e3abc6-e35d-48a8-a2c9-0d8196f2e6b8","added_by":"auto","created_at":"2024-09-04 16:08:16","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":5713,"visible":true,"origin":"","legend":"\u003cp\u003eGeographical distribution of \u003cem\u003eOctangium\u003c/em\u003e spp. from turtles around the world. References for the records are given between parentheses.\u003c/p\u003e","description":"","filename":"placeholderimage.png","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/d76e0e9ddffb31498afb75a8.png"},{"id":63997510,"identity":"e3a278ce-8a5d-48c8-b0fe-34808cb30777","added_by":"auto","created_at":"2024-09-04 17:39:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":88333514,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5018739/v1/794f5480-58a5-4a8d-a2d8-e248b4b2fc16.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003e“Reviving museum oddities: rehydrating Trematodes curiosities!” A successful method for rehydrating dried museum specimens for a revision of the genus \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eOctangium\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (Trematoda), parasites of green sea turtle \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eChelonia mydas\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eNatural History museums worldwide, in addition to housing billions of relevant specimens offering an exceptional potential parasitological dataset for taxonomical studies and various other purposes (Wood \u0026amp; Vanhove, 2023), play a crucial role as a \u0026ldquo;biodiversity\u0026rdquo; resource, not only for taxonomists but also for scientists who are dependent on accurate information that transcends specific disciplines. Additionally, as global ecosystems undergo rapid transformation, there is a significant risk of losing biodiversity information. This includes insights into the impacts of accelerated ecological change, which in turn affect human health, the sustainability of food resources, conservation efforts, and the integrity of natural systems (Hoberg et al., 2009). Moreover, collections can be considered historical and environmental benchmarks, allowing us to evaluate shifts in faunal structure. An applied aspect of this is the monitoring of invasive species and emerging diseases resulting from processes such as global climate warming, as well as other human-induced and natural phenomena.\u003c/p\u003e \u003cp\u003eIn the field of parasitology, it is not uncommon to encounter perplexity regarding taxonomy, the host, and geographic ranges of species. To address these challenges, natural history collections play a key role as they include invaluable type series and vouchers documenting associations across different temporal and spatial scales. They form thus the cornerstone of systematic research by establishing an empirical record that enhances our comprehension of the parasites as part of the biosphere. Moreover, collections are increasingly vital for the advancement of biodiversity informatics, consolidating knowledge on the identity, geographic distribution, ecology, phylogeny, population structure, and historical context of these pathogens\u0026rsquo; diversity (Hoberg et al., 2009).\u003c/p\u003e \u003cp\u003eSystematics and specimens-based collections are the foundation of an important part of what has been accomplished in parasitology and have resolved a substantial number of real-world problems in human and animal health (Brooks \u0026amp; Hoberg, 2000). Collections can serve as invaluable resources for public health responders seeking to identify the origins and distribution of disease agents. For example, remarkable success has been achieved in protecting human populations from Guinea Worm (Nematoda) once all its developmental stages and host species were sampled, preserved, documented, and analyzed. Moreover, understanding the pathways of tropical diseases like elephantiasis (caused by a Nematode), and schistosomiasis (caused by a Trematode) through various hosts requires the creation and examination of populations of potential host and vector species, both wild and domesticated. Hence, access to collections and the insights gleaned from their analyses will be crucial in comprehending and disrupting the cycles of disease transmission involving multiple species (DiEuliis et al., 2016).\u003c/p\u003e \u003cp\u003eThe Swedish Museum of Natural History (SMNH) houses a large collection of parasitic invertebrates, including part of the collections of the eminent parasitologist Professor Arthur Looss (Kuzmina \u0026amp; Holovachov, 2023). This collection includes several slides that are type material, and vials containing trematodes preserved in ethanol, along with several publication-ready and original line drawings (Bouguerche et al., 2023) along with notes on host and locality \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. \u003cb\u003eA-C)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eDuring an ongoing investigation on the systematics of Trematodes at the SMNH collections, we found vials containing \u003cem\u003eOctangium\u003c/em\u003e spp. preserved in ethanol from a host and locality matching those listed in Looss (1899) suggesting that this is the part of type material used by Looss in his study. Unfortunately, several specimens were dried out \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. \u003cb\u003eD, E).\u003c/b\u003e Some of the line drawings of parasitic Trematodes that we had, matched the plates given in Looss\u0026rsquo;s work on systematics and nomenclature of trematodes from sea turtles (Looss, 1902) \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e indicating that this is part of the type material.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eGiven their host, this collection of parasites of turtles certainly warrants more attention. Sea turtles confront a multitude of threats, including pollution, habitat degradation, the impacts of climate change, interactions with fisheries, and ingestion of marine debris (Duncan et al., 2019). Moreover, they experience intussusception, a condition where a section of the gastrointestinal tract (known as the intussusceptum) invaginates into the lumen of an adjacent portion, termed the intussuscipiens (MacPhail, 2002) resulting in partial or total obstruction of the gastrointestinal tract (Levit \u0026amp; Bauer, 1992). Interestingly, the existence of parasites is frequently regarded as a predisposing factor for intussusception (see (Duncan et al., 2019). Moreover, Duncan et al. (2019) demonstrated that parasitic infestation by \u003cem\u003eOctangium\u003c/em\u003e spp. in sea turtles can root intussusception, subsequently leading to the death of the host turtle.\u003c/p\u003e \u003cp\u003eTimely diagnosis is crucial for achieving a favorable prognosis and successful rehabilitation of the host and can only be preceded by an acute identification of the causal Trematode. Thus, we attempted to rehydrate the Trematodes \u003cem\u003eOctangium\u003c/em\u003e sp. found in the SMNH, make whole stained mounts, and investigate the material. Additionally, we examined several specimens of \u003cem\u003eO. sagitta\u003c/em\u003e and \u003cem\u003eO. hasta\u003c/em\u003e from the Invertebrate collections at the SMNH and provided detailed illustrated redescriptions. We also discuss records of \u003cem\u003eO. sagitta\u003c/em\u003e, \u003cem\u003eO. hasta\u003c/em\u003e, and previous species synonymized with \u003cem\u003eO. sagitta\u003c/em\u003e and provide a key for the identification of \u003cem\u003eOctangium\u003c/em\u003e spp.\u003c/p\u003e"},{"header":"2. Material and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Rehydration of dried specimens\u003c/h2\u003e \u003cp\u003eThe current study is based solely on A. Looss\u0026rsquo;s specimens and archival documents preserved in the archives and general-type collections of the Department of Zoology, Swedish Museum of Natural History. Several Trematodes, with notes on the host, locality, and microhabitat in the host were dried out. For the rehydration of dried brittle microscaphidiids from A. Looss\u0026rsquo;s collection, we followed the protocol of Van Cleave \u0026amp; Ross (1947) using trisodium phosphate to soften specimens prior to staining. Hard, brittle, and unyielding dry Trematodes were passed down the grades of alcohol to water and were then placed in a solution of approximately 0,25 percent of trisodium phosphate in distilled water until softened. Specimens were kept in the trisodium phosphate solution (T-Ph-S) for several hours or even days, from four hours to two weeks. No warming oven was used to attain the proper degree of softness and pliability.\u003c/p\u003e \u003cp\u003eTreated specimens in T-Ph-S were kept under observation until obtaining the desired degree of softness and translucency. One specimen was treated separately in a petri dish under a dissecting microscope, to check the progress of the treatment. Treated specimens are kept in the solution until turning from excessive hard dark brownish specimens to translucid soft specimens.\u003c/p\u003e \u003cp\u003eWhen the desired degree of softness and translucency has been reached, the treated specimens are removed from the T-Ph-S to distilled water to check the action. When softened, the treated thus treated are washed several times in distilled water, then stored in 70 ethanol.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Staining and slides mounting\u003c/h2\u003e \u003cp\u003eWhole-mounts for morphological analysis were stained with acetocarmine for 10 minutes, dehydrated in a graded ethanol series (70, 96. 100. For 20 minutes each), cleared carefully in clove oil, and mounted in Canada balsam. Drawings were made through a Nikon Eclipse i80 microscope with DIC (differential interference contrast) and a drawing tube. Drawings were scanned and redrawn on a computer with Adobe Illustrator 2023.\u003c/p\u003e \u003cp\u003eMeasurements of whole-mounts are in micrometres and indicated as the range followed by the\u003c/p\u003e \u003cp\u003enumber of measurements in parentheses. The maximum width was taken slightly behind the middle of the body following Looss (1899). The following abbreviation is used: SMNH, Swedish Museum of Natural History, Stockholm, Sweden.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Examination of comparative material\u003c/h2\u003e \u003cp\u003eThe collection also includes several total mounts and sections, prepared as described in respective original descriptions of \u003cem\u003eOctangium\u003c/em\u003e spp (Looss, 1899, 1901, 1902). Additional material examined in this study includes stained mounts of \u003cem\u003eO. sagitta\u003c/em\u003e and \u003cem\u003eO. hasta\u003c/em\u003e from Looss\u0026rsquo;s collection found in the Trematodes collection at the SMNH that were examined and studied for comparison. The studied comparative material included four whole-mounts of \u003cem\u003eO. sagitta\u003c/em\u003e (15 specimens) ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo and from Alexandria, Egypt, Eastern Mediterranean; 7 sections of \u003cem\u003eO. sagitta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo, Egypt, Eastern Mediterranean; 7 whole-mounts of \u003cem\u003eO. hasta\u003c/em\u003e (51 specimens) from ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo, Egypt, Eastern Mediterranean; 3 sections ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo, Egypt, Eastern Mediterranean. Measurements and drawings are tacking as explained above. Measurements of specimens from the SMNH Trematodes\u0026rsquo; collection were provided separately.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cb\u003eFamily Microscaphidiidae Looss, 1900\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eGenus\u003c/b\u003e \u003cb\u003eOctangium\u003c/b\u003e \u003cb\u003eLooss, 1902\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cb\u003eOctangium sagitta\u003c/b\u003e \u003cb\u003e(Looss, 1899) Looss, 1902\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eAccepted name\u003c/strong\u003e \u003cp\u003e \u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) Looss, 1902\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eUnaccepted name/ Synonyms\u003c/strong\u003e \u003cp\u003e \u003cem\u003eMicroscapha sagitta\u003c/em\u003e Looss, 1899 (Superseded combination). \u003cem\u003eMicroscaphidium sagitta\u003c/em\u003e (Looss, 189) Looss, 1901 (Superseded combination). \u003cem\u003eOctangium hasta\u003c/em\u003e Looss, 1902 (Tentative synonymy by Blair (1987) refuted). \u003cem\u003eOctangium takanoi\u003c/em\u003e Kobayashi, 1921 (Tentative synonymy by Blair (1987) refuted).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eOriginal name\u003c/strong\u003e \u003cp\u003e \u003cem\u003eMicroscapha sagitta\u003c/em\u003e Looss, 1899.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eType-host\u003c/em\u003e: \u003cem\u003eChelonia mydas\u003c/em\u003e (Testudines: Cheloniidae), the green sea turtle (Looss, 1899).\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eType-locality\u003c/strong\u003e \u003cp\u003eoff Egypt, Eastern Mediterranean (Looss, 1899).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSite in host in original description\u003c/strong\u003e \u003cp\u003eRectum (Looss, 1899).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eAdditional hosts\u003c/em\u003e: \u003cem\u003eCaretta caretta\u003c/em\u003e (Cheloniidae), the Loggerhead sea turtle (Marangi et al., 2020). \u003cem\u003eEretmochelys imbricata\u003c/em\u003e (Cheloniidae), the Hawksbill turtle (Dyer et al., 1995)\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eAdditional localities\u003c/strong\u003e \u003cp\u003eItaly, Adriatic Sea and Northern Ionian Sea, Central Mediterranean (Marangi et al., 2020). Florida, USA, Atlantic, Western-Central (Wyneken et al., 2013). Puerto Rico, Atlantic, Western-Central (Dyer et al., 1991; Dyer et al., 1995). Rio De Janeiro, Brazil, Atlantic, Southwest (Cavaco, 2021; Silva, 2020). Gulf of Mexico, USA, Atlantic, Western-Central (Overstreet et al., 2009). Queensland, Australia, Pacific, Western Central (Johnston, 1913; Johnston, 1916)\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eOther reported habitats\u003c/strong\u003e \u003cp\u003ethe large intestine (Cavaco, 2021; Dyer et al., 1991; Looss, 1902; Overstreet et al., 2009). Terminal section of the small intestine) (Looss, 1902; Overstreet et al., 2009). Gastrointestinal tract (Silva, 2020). Intestine (Johnston, 1913). Note that the report of Marangi et \u003cem\u003eal\u003c/em\u003e. (2020) was based on faecal examination to detect eggs in a faecal sample and thus the location of adults in the corresponding host is not available. Habitat in the record by Wyneken et al. (2013) and that of Dyer et al. (1995) not available.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eSpecimens deposited\u003c/em\u003e: specimens examined for morphological study, whole mounts: rehydrated specimens from A. Looss\u0026rsquo;s dried specimens\u0026rsquo; collection at the SMNH: \u003cem\u003eO. sagitta\u003c/em\u003e ex \u003cem\u003eChelonia mydas\u003c/em\u003e from \u003cb\u003eCairo\u003c/b\u003e, Egypt, Eastern Mediterranean, rehydrated, stained and mounted (SMNH type 9690\u0026ndash;9715)\u003c/p\u003e \u003cp\u003e \u003cem\u003eMaterial examined for comparison\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eWhole mounts, from A. Looss\u0026rsquo;s collection at the SMNH\u003c/em\u003e: \u003cem\u003eO. sagitta\u003c/em\u003e ex \u003cem\u003eChelonia mydas\u003c/em\u003e from Alexandria, Egypt, Eastern Mediterranean (SMNH 140048) marked as juveniles (see discussion); \u003cem\u003eO. sagitta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Alexandria, Egypt, Eastern Mediterranean (SMNH 140049); \u003cem\u003eO. sagitta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo (Abuk), Egypt, Eastern Mediterranean (SMNH 140050, 140051), \u003cem\u003eO. sagitta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo, Egypt, Eastern Mediterranean (SMNH 140052).\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSectioned material, from A. Looss\u0026rsquo;s collection at the SMNH\u003c/strong\u003e \u003cp\u003eex \u003cem\u003eO. sagitta\u003c/em\u003e from \u003cem\u003eChelonia mydas\u003c/em\u003e from Egypt, Eastern Mediterranean; 2 undefined sections (SMNH 140053, SMNH 140059), 2 \u0026ldquo;queer\u0026rdquo; sections (SMNH 140054140055), 3 sagittal sections (SMNH 140056, SMNH 140058),\u003c/p\u003e \u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Redescription (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eComparative measurements in Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Body stocky, ending posteriorly with 2 visible caudolateral projections separated by a terminal notch. Tegument thick, smooth. Mouth terminal.\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 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eHosts and localities of \u003cem\u003eOctangium\u003c/em\u003e spp. Rej., rejected synonym. \u003csup\u003e1\u003c/sup\u003e occasionally small intestine. 2 currently \u003cem\u003etaxon inquirendum\u003c/em\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\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\u003eSynonyms\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eType-host\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMicrohabitat\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eType locality\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eMicroscapha sagitta\u003c/em\u003e Looss, 1899\u003c/p\u003e \u003cp\u003e\u003cem\u003eMicroscaphidium sagitta\u003c/em\u003e (Looss, 1899)\u003c/p\u003e \u003cp\u003e\u003cem\u003eOctangium hasta\u003c/em\u003e Looss, 1902 Rej.\u003c/p\u003e \u003cp\u003e\u003cem\u003eOctangium takanoi\u003c/em\u003e Kobayashi, 1921 Rej.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eChelone mydas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRectum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEgypt, EM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Blair, 1987; Looss, 1899, 1901, 1902)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOctangium hasta\u003c/em\u003e Looss, 1902\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eOctangium sagitta\u003c/em\u003e Rej.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eChelone mydas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLarge intestine \u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEgypt, EM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Blair, 1987; Looss, 1902)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOctangium takanoi\u003c/em\u003e Kobayashi, 1921\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eOctangium sagitta\u003c/em\u003e Rej.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eChelone mydas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIntestine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSingapore, WCP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Kobayashi, 1921)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOctangium elongatum\u003c/em\u003e Chattopadhyaya, 1972\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eChelone mydas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLarge intestine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIndia, EIO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Chattopadhyaya, 1972)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOctangium microrchis\u003c/em\u003e Chattopadhyaya, 1972\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eEretmochelys imbricata\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLarge intestine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIndia, EIO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Chattopadhyaya, 1972)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOctangium hyphalum\u003c/em\u003e Blair, 1987\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eChelone mydas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePseudocaecum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAustralia, WCP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eAbbreviations: EIO., Eastern Indian Ocean. EM., Eastern Mediterranean. WCP., Western Central Pacific\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparative measurements for \u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) from the Mediterranean. * Diameter. \u003csup\u003ea\u003c/sup\u003e Looss (1899) also reported a length of 1000\u0026ndash;2000 \u0026micro;m for very young specimens. \u003csup\u003eb\u003c/sup\u003e exceptionally 8. NA, not available.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHabitat\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRectum\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIntestine\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocality\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEgypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAlexandria, Egypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCairo, Egypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eEgypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eEgypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eEgypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of specimens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 adult\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e13 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e23 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLooss (1899)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLooss (1902)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePresent study,\u003c/p\u003e \u003cp\u003erehydrated specimens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSey (1977) \u003cem\u003ein\u003c/em\u003e (Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eLooss\u0026rsquo;s (1902) type material from NHR collections (Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u0026nbsp;000 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eUp to 10 000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6776\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7061 (4231\u0026ndash;10250, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6711 (1575\u0026ndash;7863, n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6560 (4900\u0026ndash;7800)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e6970 (4300\u0026ndash;10\u0026nbsp;380)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLargest 2 000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1922\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1916 (1472\u0026ndash;2424, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1215 (834\u0026ndash;1537, n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2100 (1660\u0026ndash;2420)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1980 (1500\u0026ndash;2500)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e276\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e313 (248\u0026ndash;360, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e321 (237\u0026ndash;377, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e350 (290\u0026ndash;480)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e310 (230\u0026ndash;360, n\u0026thinsp;=\u0026thinsp;13)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e330 *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e370\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e358\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e432 (337\u0026ndash;518, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e300 (220\u0026ndash;361, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e340 (280\u0026ndash;400)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e410 (340\u0026ndash;520, n\u0026thinsp;=\u0026thinsp;13)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOesophagus length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1434\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1844 (1197\u0026ndash;2180, n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1440 (1210\u0026ndash;1660)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1590 (900\u0026ndash;2400)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior end-\u003c/p\u003e \u003cp\u003eintestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1867 (1249\u0026ndash;2411, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2179 (1422\u0026ndash;2576, n\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior testes- intestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1145\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1112 (417\u0026ndash;1773, n\u0026thinsp;=\u0026thinsp;10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e859 (655\u0026ndash;1052, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e780 (480\u0026ndash;1000)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e810 (400\u0026ndash;1400)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e860 (45 \u0026minus;\u0026thinsp;1174, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e648 (426\u0026ndash;837, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e760 (500\u0026ndash;870)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e870 (450\u0026ndash;1140, n\u0026thinsp;=\u0026thinsp;13)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e663 (186\u0026ndash;1068, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e307 (239\u0026ndash;375, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e690\u0026nbsp;(410\u0026ndash;1020)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e660 (210\u0026ndash;1150, n\u0026thinsp;=\u0026thinsp;13)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e885 (471\u0026ndash;1243, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e641 (421\u0026ndash;780, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e750 (590\u0026ndash;950)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e870 (500\u0026ndash;1210, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e630\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e649 (194\u0026ndash;1043, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e307 (227\u0026ndash;398, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e670 (560\u0026ndash;870)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e740 (230\u0026ndash;1220, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e272\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e373 (250\u0026ndash;521, n\u0026thinsp;=\u0026thinsp;5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e137 (122\u0026ndash;170, n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e270 (160\u0026ndash;320, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e280 (130\u0026ndash;440, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e203\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e293 (230\u0026ndash;454, n\u0026thinsp;=\u0026thinsp;5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e154 (115\u0026ndash;193, n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e240\u0026nbsp;(130\u0026ndash;310, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e240 (100\u0026ndash;360, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of excretory diverticula\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u0026ndash;7 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e77 (70\u0026ndash;81, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e78 (72\u0026ndash;86, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003cp\u003e49 (45\u0026ndash;55, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e79\u0026ndash;87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e75\u0026ndash;85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e51 (42\u0026ndash;56, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e56\u0026ndash;64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e48\u0026ndash;60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eAbbreviations: NA, not available. E.M., Eastern Mediterranean. SW.A. Southwest Atlantic.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eOral suckers small, rounded to elliptical, with a pair of intramural diverticula distally. Oesophagus long, straight, thick-walled, with an anterior thickening of its musculature at posterior level of oral sucker. Oesophagus ending posteriorly with a voluminous muscular bulb, straight or almost so, with distinct muscular bulb at posterior end. Esophageal bulb with a wide visible lumen, surrounded by numerous glandular cells. Intestinal bifurcation anterior to tests. Caeca large, thick-walled, visibly wrinkled in most specimens, ending close posterior end of body.\u003c/p\u003e \u003cp\u003eTestes intercaecal in middle third of body, tandem. Anterior testis always posterior to intestinal bifurcation. Seminal vesicle immediately posterior to, elongated, slightly sinuous in some parts, ending anteriorly by a thin ejaculatory duct. Hermaphroditic duct not examined. Genital pore posterior to sucker.\u003c/p\u003e \u003cp\u003eOvary small, always posterior to testes. Oviduct thin, extended by a large uterus. Uterus extending anteriorly and ending by a thin metraterm. Metraterm joining ejaculatory duct close to genital pore. Vitellarium follicular, arranged in two lateral fields and one median field. Lateral vitelline fields not co-existing entirely with caeca, extending from level of intestinal bifurcation, posteriorly before ends of caeca. Median vitelline field extending from posterior level of ovary to posterior ends of caeca. Eggs in operculated.\u003c/p\u003e \u003cp\u003eExcretory rosette formed of 5\u0026ndash;8 diverticula.\u003c/p\u003e \u003cp\u003e \u003cb\u003eOctangium hasta\u003c/b\u003e \u003cb\u003eLooss, 1902\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eAccepted name\u003c/strong\u003e \u003cp\u003e \u003cem\u003eOctangium hasta\u003c/em\u003e Looss, 1902\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eUnaccepted name/ Synonyms\u003c/strong\u003e \u003cp\u003e \u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) Looss, 1902 (Tentative synonymy by Blair (1987) refuted)\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eOriginal name\u003c/strong\u003e \u003cp\u003e \u003cem\u003eOctangium hasta\u003c/em\u003e Looss, 1902.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eType-host\u003c/em\u003e: \u003cem\u003eChelonia mydas\u003c/em\u003e (Testudines: Cheloniidae), the green sea turtle (Looss, 1902).\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eType-locality\u003c/strong\u003e \u003cp\u003eCairo, Egypt, Eastern Mediterranean (Looss, 1902).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSite in host in original description\u003c/strong\u003e \u003cp\u003eLarge intestine (Looss, 1902).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eSpecimens examined for morphological study\u003c/em\u003e:\u003c/p\u003e \u003cp\u003eWhole mounts, from A. Looss\u0026rsquo;s collection at the SMNH: \u003cem\u003eO. hasta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Alexandria, Egypt, Eastern Mediterranean (SMNH 140048) marked as juveniles (see discussion); \u003cem\u003eO. hasta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo, Egypt, Eastern Mediterranean (SMNH 140038\u0026ndash;140044).\u003c/p\u003e \u003cp\u003eSections, from A. Looss\u0026rsquo;s collection at the SMNH: \u003cem\u003eO. hasta\u003c/em\u003e ex \u003cem\u003eC. mydas\u003c/em\u003e from Cairo, Egypt, Eastern Mediterranean (SMNH 140045\u0026ndash;140047).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e1.1. Redescription (Figs.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e, \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e)\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eMeasurements in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Body elongate, maximum width at level of midbody. Width uniform in main part of the body, narrowing anteriorly and posteriorly. Body ending posteriorly with 2 caudolateral projections) separated by a terminal notch. Tegument thick, smooth. Mouth terminal.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparative measurements for \u003cem\u003eOctangium sagitta\u003c/em\u003e (Looss, 1899) from the Pacific. * Diameter. \u003csup\u003eA\u003c/sup\u003e Looss (1899) also reported a length of 1000\u0026ndash;2000 \u0026micro;m for very young specimens. \u003csup\u003eb\u003c/sup\u003eexceptionally 8.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHabitat\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eLarge intestine\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eGastrointestinal tract\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocality\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlexandria, Egypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCairo, Egypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEgypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eQueensland, WCP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePuerto Rico, WCA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eBrazil, SWA.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eBrazil, SWA.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of specimens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 adult\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePresent study,\u003c/p\u003e \u003cp\u003erehydrated specimens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eFischthal \u0026amp; Acholonu 1976 (Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eCavaco (2021)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e(Silva, 2020)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6776\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7061 (4231\u0026ndash;10250, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6711 (1575\u0026ndash;7863, n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8440 (6140\u0026ndash;10\u0026nbsp;800)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5130 (4000\u0026ndash;6000)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6000 (4540\u0026ndash;7690)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5580\u0026ndash;6470\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1922\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1916 (1472\u0026ndash;2424, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1215 (834\u0026ndash;1537, n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2480 (1880\u0026ndash;2780)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1350 (1100 \u0026minus;\u0026thinsp;1540)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1700 (990\u0026ndash;2980)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3760\u0026ndash;4310\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e276\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e313 (248\u0026ndash;360, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e321 (237\u0026ndash;377, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e510 (300\u0026ndash;630, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e320\u0026nbsp;(260\u0026ndash;340)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e237 (158\u0026ndash;351)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e510\u0026ndash;580\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e358\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e432 (337\u0026ndash;518, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e300 (220\u0026ndash;361, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e520 (450\u0026ndash;590, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e270 (220\u0026ndash;320)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e285 (214\u0026ndash;377)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e530\u0026ndash;630\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOesophagus length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1434\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1844 (1197\u0026ndash;2180, n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1780 (1320\u0026ndash;2400)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1380 (1160\u0026ndash; 1520)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e923 (490\u0026ndash;1269)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1020\u0026ndash;1270\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior end-\u003c/p\u003e \u003cp\u003eintestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1867 (1249\u0026ndash;2411, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2179 (1422\u0026ndash;2576, n\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e280\u0026ndash;310\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior testes- intestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1145\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1112 (417\u0026ndash;1773, n\u0026thinsp;=\u0026thinsp;10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e859 (655\u0026ndash;1052, n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e960 (740\u0026ndash;1400)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e500 (320\u0026ndash;580)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e860 (45 \u0026minus;\u0026thinsp;1174, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e648 (426\u0026ndash;837, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1030 (650\u0026ndash;1430)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e450 (280\u0026ndash;580)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e667 (381\u0026ndash;902)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e500\u0026ndash;610\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e663 (186\u0026ndash;1068, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e307 (239\u0026ndash;375, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e750\u0026nbsp;(560\u0026ndash;1150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e230 (160\u0026ndash;340)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e666 (383\u0026ndash;994)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e950\u0026ndash;1090\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e885 (471\u0026ndash;1243, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e641 (421\u0026ndash;780, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1080 (680\u0026ndash;1380)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e440 (290\u0026ndash;530)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e628 (468\u0026ndash;912)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e520\u0026ndash;580\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e630\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e649 (194\u0026ndash;1043, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e307 (227\u0026ndash;398, n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e840 (590\u0026ndash;1360)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e230 (140\u0026ndash;350)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e489 (284\u0026ndash;755)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e960\u0026ndash;1110\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e272\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e373 (250\u0026ndash;521, n\u0026thinsp;=\u0026thinsp;5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e137 (122\u0026ndash;170, n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e310 (210\u0026ndash;370)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e130 (90\u0026ndash;180)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e206 (146\u0026ndash;258)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e450\u0026ndash;510\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e203\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e293 (230\u0026ndash;454, n\u0026thinsp;=\u0026thinsp;5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e154 (115\u0026ndash;193, n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e290 (150\u0026ndash;380)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e70 (60\u0026ndash;110)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e176 (99\u0026ndash;245)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e290\u0026ndash;320\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of excretory diverticula\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e77 (70\u0026ndash;81, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e78 (72\u0026ndash;86, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003cp\u003e49 (45\u0026ndash;55, n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(71\u0026ndash;83, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e67\u0026ndash;75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e83 (71\u0026ndash;92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51 (42\u0026ndash;56, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(48\u0026ndash;52, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e39\u0026ndash;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e49 (42\u0026ndash;57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eAbbreviations: NA, not available. E.M., Eastern Mediterranean. WCA., Western-central Atlantic. WCP., Western central pacific. SWA. Southwest Atlantic.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eOral sucker somewhat rectangular. Oesophagus long, thick walled, with a wide lumen, ending posteriorly with a distinct oesophageal bulb. Esophageal bulb with a wide lumen, surrounded by numerous glandular cells. Intestinal bifurcation at anterior third. Caeca straight.\u003c/p\u003e \u003cp\u003eTestes pre-ovarian, intercaecal in midbody, posterior to intestinal bifurcation, oval, disposed in tandem. Eggs in utero operculated. Seminal vesicle posterior to anterior tests. Ejaculatory duct joining metraterm. Hermaphroditic duct not examined. Genital pore posterior to ventral sucker.\u003c/p\u003e \u003cp\u003eOvary small, ventral, always posterior to testes. Oviduct thin, extended by the uterus. Uterus extending anteriorly and ending by a thin metraterm. Vitellarium arranged as in \u003cem\u003eO. sagitta\u003c/em\u003e. Lateral vitelline co-existing partially with caeca, anterior limit of lateral vitelline fields not attending level of intestinal bifurcation, posterior limit before ends of caeca. Median vitelline field extending from posterior level of ovary and not reaching posterior ends of caeca. Vitellarium follicular, arranged in two lateral fields and one median field. Lateral vitelline fields not co-existing entirely with caeca, extending from level of intestinal bifurcation, posteriorly before ends of caeca. Median vitelline field extending from posterior level of ovary to posterior ends of caeca. Eggs in operculated.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Looss\u0026rsquo;s Trematodes collection\u003c/h2\u003e \u003cp\u003eArthur Looss died after a long illness on May 4, 1923, at Giessen. Born on May 16, 1861, at Chemnitz, he received his education in his native city and at Lodz in Poland, then at the University of Leipzig where he received the degree of Doctor of Philosophy, his thesis being on the Trematodes (Vaughan, 1924). He was for many years, a professor of parasitology and biology at the School of Medicine in Cairo. He pursued his work until after the outburst of the World War when he retired from his chair and returned to Germany (Vaughan, 1924).\u003c/p\u003e \u003cp\u003eLooss dedicated his life to the study of helminthology, not only systematics and nomenclature as he made outstanding inputs to the medical aspect of helminthology. One of the spectacular discoveries of his career, was when he was sent by Leuckart to Egypt to study the transmission of bilharzia, where there he became interested in hookworm and due to an accidental infection of himself that made the discovery of the aptitude of larval worm to enter the skin, then transported to the heart, lungs and intestinal tract (Vaughan, 1924). Certainly, by the finding of the mode of infection Looss also clearly helped determine the way to prevent the disease. Hence, it is only fair to say that Looss not only \u0026ldquo;made for himself a name as one of the most distinguished of helminthologists\u0026rdquo; but also \u0026ldquo;put the world under a debt of gratitude to him\u0026rdquo;.\u003c/p\u003e \u003cp\u003eAfter his death, his collection was sold to different museum and part of it to the Swedish Museum of Natural history (Kuzmina \u0026amp; Holovachov, 2023). This collection includes numerous slides that are actually type material, and vials comprising ethanol-preserved trematodes, and various publication-ready and original line drawings (Bouguerche et al., 2023) beside notes of records on host and locality. For \u003cem\u003eO. sagitta\u003c/em\u003e, some of the line drawings of parasitic Trematodes that we had, matched the plates given in Looss\u0026rsquo;s work on systematics and nomenclature of trematodes from sea turtles (Looss, 1902) \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e indicating that this is part of the type material.\u003c/p\u003e \u003cp\u003eThus, we attempted to rehydrate the Trematodes \u003cem\u003eO. sagitta\u003c/em\u003e and we made whole stained mounts that we used to investigate these Trematodes and the systematics of the genus. Hence, these Trematodes even in compromised condition, provided still instrumental data for the systematics of the genus \u003cem\u003eOctangium\u003c/em\u003e, aiding in the identification of \u003cem\u003eOctangium\u003c/em\u003e spp. Advances in genetic and molecular techniques will certainly also allow to extraction of DNA from degraded specimens, offering insights into evolutionary relationships and the genetic structure of populations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Rehydration of dried specimens\u003c/h2\u003e \u003cp\u003eVan Cleave and Ross (1947) stated that freshly preserved specimens become soft and translucent shortly after, while hard dry specimens soften after several hours or even days. Herein, all the microscaphidiids from A. Looss\u0026rsquo;s collection were hard, brittle, and unyielding after long preservation and thus required a longer treatment up to four hours in the rehydrating solution. However, smaller Trematodes, such as \u003cem\u003eLecithocladium excisum\u003c/em\u003e (Rudolphi, 1819) (in an upcoming study) required shorter rehydrating time and became softened within 45 minutes at the earliest. Van Cleave and Ross (1947) also mentioned that hard dry specimens might require even days in a warming oven before they attain the proper degree of softness and pliability. However, no warming oven was used to attain the proper degree of softness and pliability. The only difference was examined regarding the time of rehydration. Specimens that were kept for several days in the rehydrating solution tend to clear better in clove oil after the staining.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Systematics of \u003cem\u003eOctangium\u003c/em\u003e spp.\u003c/h2\u003e \u003cp\u003eMicroscaphidiid Trematodes of the genus \u003cem\u003eOctangium\u003c/em\u003e Looss, 1902 are typically parasites of the intestine of marine turtles (Cheloniidae), in nearly all tropical and subtropical seas. Members of this genus are readily distinguished by a body with a profound posterior terminal notch, visible between paired caudolateral projections, a simple not recurved excretory vesicle, and the presence of a rosette of diverticula present just proximal to the excretory pore (Blair, 2005).\u003c/p\u003e \u003cp\u003eThe genus \u003cem\u003eOctangium\u003c/em\u003e is in need of systematic revision. Overall, 7 species have been assigned to the genus \u003cem\u003eOctangium\u003c/em\u003e (WoRMS, 2023): \u003cem\u003eO. sagitta\u003c/em\u003e of which \u003cem\u003eO. hasta\u003c/em\u003e, and \u003cem\u003eO. takanoi\u003c/em\u003e Kobayashi, 1921, were considered synonyms; and \u003cem\u003eO. hyphalum\u003c/em\u003e Blair, 1987, of which \u003cem\u003eO. takanoi\u003c/em\u003e Kobayashi sensu Mehrotra (1973) and Tandon and Gupta (1981) was considered a synonym (Blair, 2005). The most recent species are \u003cem\u003eO. elongatum\u003c/em\u003e Chattopadhyaya, 1972, from the large intestine of the green sea turtle \u003cem\u003eChelonia mydas\u003c/em\u003e and \u003cem\u003eO. microrchis\u003c/em\u003e Chattopadhyaya, 1972 from the hawksbill sea turtle \u003cem\u003eEretmochelys imbricata\u003c/em\u003e from the eastern Indian Ocean, off India, are both currently \u003cem\u003etaxon inquirendum\u003c/em\u003e (Blair, 1987). Another Microscaphidiid species from marine turtles assigned previously to this genus is \u003cem\u003eO. travassosi\u003c/em\u003e (Ruiz, 1943), first described from the intestine of an unidentified marine turtle referred to as \u0026ldquo;\u003cem\u003eTartaruga marinha\u003c/em\u003e (sp.?)\u0026rdquo; from the southwest Atlantic, off Brazil as \u003cem\u003eNeoctangium travassosi\u003c/em\u003e Ruiz, 1943 (Ruiz, 1943), then placed in the genus \u003cem\u003eOctangium\u003c/em\u003e when Yamaguti (1958) synonymized \u003cem\u003eNeoctangium\u003c/em\u003e with \u003cem\u003eOctangium\u003c/em\u003e, first without explanation (Blair, 1987), then justified his decision and wrote \u0026ldquo;Ruiz (1943) distinguished \u003cem\u003eNeoctangium\u003c/em\u003e Ruiz, 1943 from \u003cem\u003eOctangium\u003c/em\u003e simply because of the presence of 4 pairs of cephalic [sic] papillae\u0026rdquo; (Yamaguti, 1971). Blair (1987) refuted the synonymy between the two genera and considered it \u0026ldquo;unreasonable\u0026rdquo; as Ruiz (1943) omitted any mention of the excretory system in his description. Moreover, Blair (1987) demonstrated that the arrangement of excretory system in \u003cem\u003eNeoctangium\u003c/em\u003e (with an elongate recurved bladder, lacking a rosette of diverticula proximal to the excretory pore, reception of excretory ducts at a single median point proximally; a ventral excretory pore) is highly dissimilar from that of \u003cem\u003eOctangium\u003c/em\u003e spp and resurrected \u003cem\u003eNeoctangium\u003c/em\u003e based upon. Hence, the genus today remains bispecific, with \u003cem\u003eO. sagitta\u003c/em\u003e and \u003cem\u003eO. hyphalum\u003c/em\u003e Blair, 1987, first described from the Pseudocaecum and large intestine of also the same host, \u003cem\u003eC. Mydas\u003c/em\u003e from the western central pacific, off Queensland (Blair, 1987). In the following section, we discuss previous synonymies proposed within this genus.\u003c/p\u003e \u003cp\u003eTwo species have been synonymised with the type species \u003cem\u003eO. sagitta\u003c/em\u003e. The first is \u003cem\u003eO. takanoi\u003c/em\u003e (Blair, 1987). \u003cem\u003eOctangium takanoi\u003c/em\u003e was first described from the same host as \u003cem\u003eO. sagitta\u003c/em\u003e, off Singapore, Western Central Pacific (Kobayashi, 1921). Blair (1987) synonymised it with \u003cem\u003eO. sagitta\u003c/em\u003e based on examining figures of Kobayashi (1921). Even though the eggs of \u003cem\u003eO. takanoi\u003c/em\u003e and those of \u003cem\u003eO. sagitta\u003c/em\u003e do indeed overlap (despite Kobayashi (1921) distinguishing it from its congeners by eggs size), \u003cem\u003eO. takanoi\u003c/em\u003e can be easily distinguished from \u003cem\u003eO. sagitta\u003c/em\u003e by being twice smaller (5500 \u0026times;1200 \u003cem\u003evs\u003c/em\u003e. 4231\u0026ndash;10250 \u0026times; 1472\u0026ndash;2424), by the shape of the oral sucker (rectangular \u003cem\u003evs\u003c/em\u003e. rounded) and especially by the extent of vitellaria, with their anterior end situated at the level of the anterior margin of the testes in \u003cem\u003eO. takanoi\u003c/em\u003e \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eA\u003cb\u003e)\u003c/b\u003e, while they extend to the intestinal bifurcation in \u003cem\u003eO. sagitta\u003c/em\u003e \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eG, H\u003cb\u003e)\u003c/b\u003e. Additionally, they can be easily distinguished by more anterior placing of the testes in \u003cem\u003eO. takanoi\u003c/em\u003e (both testes are in the anterior half in \u003cem\u003eO. takanoi\u003c/em\u003e. We refute thus the synonymy between the two species, and we reinstate \u003cem\u003eO. takanoi\u003c/em\u003e as a valid species.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eOctangium takanoi\u003c/em\u003e was reported by Mehrotra (1973) in an abstract communicated by N. K. Gupta from India without giving any additional information (Blair, 1987). Subsequently, Tandon and Gupta (1981) provided a redescription and morphometrical data of \u003cem\u003eO. takanoi\u003c/em\u003e from the intestine of \u003cem\u003eC. mydas\u003c/em\u003e from the Gulf of India, Eastern Indian Ocean. The microscaphidiids reported by Tandon and Gupta (1981) (that we refer to in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e as \u003cem\u003eO. takanoi sensu\u003c/em\u003e Tandon and Gupta (1981)) are larger than \u003cem\u003eO. takanoi\u003c/em\u003e and have larger eggs. Most importantly, in \u003cem\u003eO. takanoi\u003c/em\u003e the vitellarium extends to the anterior margin of the anterior testis while in \u003cem\u003eO. takanoi sensu\u003c/em\u003e Tandon and Gupta (1981), the vitellarium extends about the middle of the posterior testis \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eB\u003cb\u003e)\u003c/b\u003e and the two populations can be easily distinguished by the more anterior placement of tests in \u003cem\u003eO. takanoi\u003c/em\u003e. Hence, the microscaphidiids reported by Tandon and Gupta (1981) are not \u003cem\u003eO. takanoi\u003c/em\u003e. We note that \u003cem\u003eO. takanoi sensu\u003c/em\u003e Tandon and Gupta (1981) resembles \u003cem\u003eO. hyphalum\u003c/em\u003e, in which the vitellarium\u0026rsquo;s anterior limit near the point of contact between testes \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eC\u003cb\u003e)\u003c/b\u003e and the measurements of different body parts and of eggs overlap. Hence, as previously suggested by Blair (1987), the two populations are highly likely conspecific.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparative measurements for \u003cem\u003eOctangium hasta\u003c/em\u003e Looss, 1902. * Diameter.\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHost\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eChelonia mydas\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eChelonia mydas\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eChelonia mydas\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eChelonia mydas\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHabitat\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLarge intestine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e?\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocality\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEgypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCairo, Egypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCairo, Egypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCairo, Egypt, EM.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of specimens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12 juveniles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(Looss, 1902).\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLooss\u0026rsquo;s (1902) type material from NHR collections (Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u0026ndash;3300, max 4000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2953 (2148\u0026ndash;3950, n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2187 (1569\u0026ndash;2942, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2940 (2150\u0026ndash;3880)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUp to 900\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e789 (595\u0026ndash;1128, n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e577 (412\u0026ndash;754, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e830 (630\u0026ndash;1150)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e187 (124\u0026ndash;251, n\u0026thinsp;=\u0026thinsp;27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e162 (135\u0026ndash;198, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e190 (150\u0026ndash;240)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e199 (117\u0026ndash;261, n\u0026thinsp;=\u0026thinsp;27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e158 (128\u0026ndash;195, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e200 (150\u0026ndash;270)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOesophagus length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e758 (509\u0026ndash;1049, n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e595 (445\u0026ndash;717, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e770 (540\u0026ndash;1000)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior end- Intestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e977 (709\u0026ndash;1278, n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e758 (555\u0026ndash;904, n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior testes- intestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e439 (302\u0026ndash;579, n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e344 (205\u0026ndash;502, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e370 (200\u0026ndash;490)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e236 (147\u0026ndash;470, n\u0026thinsp;=\u0026thinsp;28)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e109 (35\u0026ndash;227, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e230 (130\u0026ndash;380)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e157 (107\u0026ndash;281, n\u0026thinsp;=\u0026thinsp;28)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73 (20\u0026ndash;154, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e200 (110\u0026ndash;380)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e246 (129\u0026ndash;500, n\u0026thinsp;=\u0026thinsp;26)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e115 (32\u0026ndash;223, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e230 (110\u0026ndash;380)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e156 (99\u0026ndash;270, n\u0026thinsp;=\u0026thinsp;26)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e71 (24\u0026ndash;145, n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e190 (100\u0026ndash;370)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e134 (94\u0026ndash;203, n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72 (66\u0026ndash;78, n\u0026thinsp;=\u0026thinsp;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100 (60\u0026ndash;150)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e105 (67\u0026ndash;249, n\u0026thinsp;=\u0026thinsp;8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e57 (56\u0026ndash;57, n\u0026thinsp;=\u0026thinsp;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e80 (60\u0026ndash;110)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of excretory diverticula\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78 (68\u0026ndash;85, n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e71\u0026ndash;87\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52 (41\u0026ndash;62, n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e48\u0026ndash;58\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eAbbreviations: NA, not available. E.M., Eastern Mediterranean.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparative measurements for \u003cem\u003eOctangium\u003c/em\u003e spp. * Diameter.\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\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\u003e\u003cem\u003eOctangium sagitta\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eO. hasta\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eO. hyphalum\u003c/em\u003e\u003c/p\u003e \u003cp\u003eBlair, 1987\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eO. takanoi\u003c/em\u003e\u003c/p\u003e \u003cp\u003eKobayashi, 1921\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eO. takanoi sensu\u003c/em\u003e Tandon and Gupta (1981)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHost\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c6\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eChelonia mydas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHabitat\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eED\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePseudocaecum, large intestine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIntestine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eIntestine\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocality\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCairo, Egypt, E. M.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCairo, Egypt, EM.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eQueensland\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSingapore, Western Central Pacific\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eIndia, Eastern Indian Ocean\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of specimens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 adults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePresent study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(Blair, 1987)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(Kobayashi, 1921)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTandon and Gupta (1981)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7061 (4231\u0026ndash;10250)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2953 (2148\u0026ndash;3950)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3040\u0026ndash;6520 (4580)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5160\u0026ndash;7800\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1916 (1472\u0026ndash;2424)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e789 (595\u0026ndash;1128)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1100\u0026ndash;2500 (1710)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1240\u0026ndash;1980\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e313 (248\u0026ndash;360)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e187 (124\u0026ndash;251)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e220\u0026ndash;460 (320)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e290\u0026ndash;400\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOral sucker width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e432 (337\u0026ndash;518)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e199 (117\u0026ndash;261)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e300\u0026ndash;530 (380)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e170\u0026ndash;340\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOesophagus length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e758 (509\u0026ndash;1049)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e620\u0026ndash;1280 (910)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1420\u0026ndash;2060\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of excretory diverticula\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior end- Intestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1867 (1249\u0026ndash;2411)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e977 (709\u0026ndash;1278)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance anterior testes- intestinal bifurcation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1112 (417\u0026ndash;1773)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e439 (302\u0026ndash;579)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80\u0026ndash;280 (170)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e860 (45 \u0026minus;\u0026thinsp;1174)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e236 (147\u0026ndash;470)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e300\u0026ndash;940 (540)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e400\u0026ndash;890\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e663 (186\u0026ndash;1068)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e157 (107\u0026ndash;281)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e280\u0026ndash;1040 (530)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e360\u0026ndash;990\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e885 (471\u0026ndash;1243)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e246 (129\u0026ndash;500)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e280\u0026ndash;1030 (540)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e410\u0026ndash;870\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior testis width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e649 (194\u0026ndash;1043)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e156 (99\u0026ndash;270)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e240\u0026ndash;980 (510)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e330\u0026ndash;990\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e373 (250\u0026ndash;521)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e134 (94\u0026ndash;203)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e120\u0026ndash;480 (240)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e150\u0026ndash;230\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvary width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e293 (230\u0026ndash;454)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e105 (67\u0026ndash;249)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e110\u0026ndash;300 (200)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e90\u0026ndash;250\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e77 (70\u0026ndash;81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78 (68\u0026ndash;85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e67\u0026ndash;79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e70\u0026ndash;75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e58\u0026ndash;78\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEggs width\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51 (42\u0026ndash;56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52 (41\u0026ndash;62)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e44\u0026ndash;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e44\u0026ndash;53\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\u003eAnother current ambiguity within this genus is related to the type species of the genus, \u003cem\u003eO. sagitta\u003c/em\u003e with the related synonyms. \u003cem\u003eOctangium sagitta\u003c/em\u003e was first described by Looss (1899) as \u003cem\u003eMicroscapha sagitta\u003c/em\u003e Looss, 1899, from the rectum of the Green sea turtle \u003cem\u003eC. mydas\u003c/em\u003e. In his subsequent comments on the names previously suggested for some \u0026ldquo;Distomid\u0026rdquo; genera, Looss (1900) renamed the corresponding genus \u003cem\u003eMicroscapha\u003c/em\u003e Looss, 1899, \u003cem\u003eMicroscaphidium\u003c/em\u003e Looss, 1900 before subsequently placing \u003cem\u003eMicroscapha sagitta\u003c/em\u003e in the latest genus (Looss, 1901). It was at last placed in the genus \u003cem\u003eOctangium\u003c/em\u003e Looss, 1902 (Looss, 1902). Blair (1987) synonymised \u003cem\u003eO. sagitta\u003c/em\u003e with \u003cem\u003eO. hasta\u003c/em\u003e, first described from the large intestine of the same host, \u003cem\u003eC. mydas\u003c/em\u003e from the Eastern Mediterranean, off Egypt (Looss, 1902). In the current study, we compared \u003cem\u003eO. sagitta\u003c/em\u003e to \u003cem\u003eO. hasta\u003c/em\u003e, and the two species can be easily distinguished by measurements, with \u003cem\u003eO. hasta\u003c/em\u003e being significantly smaller in all body measurements (see also \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e, where all adult specimens were drawn to the same scale\u003cb\u003e)\u003c/b\u003e. More importantly, \u003cem\u003eO. sagitta\u003c/em\u003e and \u003cem\u003eO. hasta\u003c/em\u003e can be easily distinguished by the shape of the oral sucker \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eG, H \u003cb\u003evs\u003c/b\u003e. \u003cb\u003eD-F)\u003c/b\u003e. Thus, we reinstate \u003cem\u003eO. hasta\u003c/em\u003e as a valid species. We summarize the distribution of current valid species in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e and we provide a diagnostic key to species of the genus.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eKey to Species\u003c/b\u003e \u003c/p\u003e \u003cp\u003eLateral vitelline fields with anterior limit close to fork of caeca, oral sucker rounded....................\u003cem\u003eO. sagitta\u003c/em\u003e\u003c/p\u003e \u003cp\u003eLateral vitelline fields with anterior limit close to fork of caeca, oral sucker rectangular.................\u003cem\u003eO. hasta\u003c/em\u003e\u003c/p\u003e \u003cp\u003eLateral vitelline fields with anterior limit beyond point of contact between testes .......................\u003cem\u003eO. takanoi\u003c/em\u003e\u003c/p\u003e \u003cp\u003eLateral vitelline fields with anterior limit near point of contact between testes ........................\u003cem\u003eO. hyphalum\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eWe thank Dr. Christopher Blanar, Professor of Biology from the Nova Southeastern University. U.S.A. and Dr. Whitney Preisser, Professor at Kennesaw State University, Georgia (KSU) for suggesting the methods to rehydrate specimens. Special thanks to Adrian Lenninger for kindly generating accession numbers. This research was funded by the Swedish Taxonomy Initiative, Artdatabanken, Swedish University of Agricultural Sciences within the scope of the project \u0026ldquo;Taxonomy and systematics of digenetic trematodes parasitising fishes of Sweden\u0026rdquo; (dha 2019.4.3\u0026ndash;48).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBlair, D. (1987). A revision of the subfamily Octangiinae (Platyhelminthes, Digenea, Microscaphidiidae) parasitic in marine turtles (Reptilia, Chelonia).. \u003cem\u003eAustralian Journal of Zoology\u003c/em\u003e, \u003cem\u003e35\u003c/em\u003e (1), 75\u0026ndash;92. https://doi.org/https://doi.org/10.1071/zo9870075\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBlair, D. (2005). Family Microscaphidiidae Looss, 1900. In \u003cem\u003eKeys to the Trematoda: Volume 2\u003c/em\u003e (pp. 193\u0026ndash;211). CABI Publishing Wallingford UK.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBouguerche, C., Huston, D. C., Cribb, T. H., Karlsbakk, E., Ahmed, M., \u0026amp; Holovachov, O. (2023). Hidden in the fog: morphological and molecular characterisation of D\u003cem\u003eerogenes varicus sensu stricto\u003c/em\u003e (Trematoda, Derogenidae) from Sweden and Norway, and redescription of two poorly known \u003cem\u003eDerogenes\u003c/em\u003e species. \u003cem\u003eParasite\u003c/em\u003e, \u003cem\u003e30\u003c/em\u003e, 35. https://doi.org/10.1051/parasite/2023030 (Cach\u0026eacute; dans le brouillard : caract\u0026eacute;risation morphologique et mol\u0026eacute;culaire de Derogenes varicus sensu stricto (Trematoda, Derogenidae) de Su\u0026egrave;de et de Norv\u0026egrave;ge, et redescription de deux esp\u0026egrave;ces de Derogenes peu connues.)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrooks, D. R., \u0026amp; Hoberg, E. P. (2000). 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Why museums matter: a tale of pinworms (Oxyuroidea: Heteroxynematidae) among pikas (\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eOchotona princeps\u003c/span\u003e and \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eO. collaris\u003c/span\u003e) in the American West. \u003cem\u003eJournal of Parasitology\u003c/em\u003e, \u003cem\u003e95\u003c/em\u003e, 490\u0026ndash;501.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJohnston, S. (1913). Memoirs: On some Queensland trematodes, with anatomical observations and descriptions of new species and genera. \u003cem\u003eJournal of Cell Science\u003c/em\u003e, \u003cem\u003e2\u003c/em\u003e(235), 361\u0026ndash;400.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJohnston, T. H. T. H. (1916). A census of the endoparasites recorded as occurring in Queensland, arranged under their hosts. \u003cem\u003eProceedings of the Royal Society of Queensland\u003c/em\u003e, \u003cem\u003e28\u003c/em\u003e, 31\u0026ndash;79.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKobayashi, H. (1921). On some digenetic trematodes in Japan. \u003cem\u003eParasitology\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e, 380\u0026ndash;410.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuzmina, T., \u0026amp; Holovachov, O. (2023). Equine Strongylidae and other parasitic nematodes described by Arthur Looss during 1895\u0026ndash;1911 in the collections of the Swedish Museum of Natural History. \u003cem\u003eZootaxa\u003c/em\u003e, \u003cem\u003e5227\u003c/em\u003e(2), 151\u0026ndash;193.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLevit, L., \u0026amp; Bauer, M. (1992). Intussusception in dogs and cats: A review of thirty-six cases. \u003cem\u003eCanadian Veterinary Journal, Canad\u0026aacute;\u003c/em\u003e, \u003cem\u003e33\u003c/em\u003e(10), 660\u0026ndash;664.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLooss, A. (1899). Weitere Beitr\u0026auml;ge zur Kenntniss der Trematoden-Fauna Aegyptens, zugleich Versuch einer nat\u0026uuml;rliden Gliederung des Genus Distomum Retzius. \u003cem\u003eZoologische Jahrb\u0026uuml;cher Abteilung f\u0026uuml;r Systematik, Geographie und Biologie der Tiere\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e, 521\u0026ndash;784.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLooss, A. (1900). Nachtr\u0026auml;gliche Bemerkungen zu den Namen der von mir vorgeschlagenen Distomidengattungen. \u003cem\u003eZoologischer Anzeiger\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e, \u003cem\u003e23\u003c/em\u003e, 601\u0026ndash;608.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLooss, A. (1901). Ueber Trematoden aus Seeschildkr\u0026ouml;ten der egyptischen K\u0026uuml;sten. (Notizen zur Helminthologie Egyptens. 4). \u003cem\u003eCentralblatt. Bakteriol. 1 Abt\u003c/em\u003e, \u003cem\u003e30\u003c/em\u003e, 555\u0026ndash;569, 618\u0026ndash;625.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLooss, A. (1902). \u0026Uuml;ber neue und bekannte Trematoden aus Seeschildr\u0026ouml;ten. Nebst Er\u0026ouml;rterungen zur Systematik un Nomenclatur. \u003cem\u003eZoologische Jahrb\u0026uuml;cher. Abteilung f\u0026uuml;r Systematik Okologie und Geographie der Tiere.\u003c/em\u003e, \u003cem\u003e16\u003c/em\u003e, 411\u0026ndash;894.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMacPhail, C. (2002). Gastrointestinal obstruction. \u003cem\u003eClinical Techniques in Small Animal Practice\u003c/em\u003e, \u003cem\u003e17\u003c/em\u003e(4), 178\u0026ndash;183.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarangi, M., Carlino, P., Profico, C., Olivieri, V., Totaro, G., Furii, G., Marzano, G., \u0026amp; Papini, R. A. (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. \u003cem\u003eInternational Journal for Parasitology: Parasites and Wildlife\u003c/em\u003e, \u003cem\u003e11\u003c/em\u003e, 207\u0026ndash;212.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOverstreet, R. M., Cook, J. O., \u0026amp; Heard, R. W. (2009). Trematoda (platyhelminthes) of the Gulf of Mexico. \u003cem\u003eGulf of Mexico\u0026mdash;origins, waters, and biota\u003c/em\u003e, \u003cem\u003e1\u003c/em\u003e, 419\u0026ndash;486.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRuiz, J. M. (1943). \u003cem\u003eNeoctangium travassosi\u003c/em\u003e gen. n., sp, n. (Trematoda : Paramphistomoidea) parasito do quelBnio marinho. Chave dos gineros da familia Microscaphidiidae Travassos, 1922. \u003cem\u003eMem\u0026oacute;rias do Instituto Butantan (Sao Paulo) 17\u003c/em\u003e, 35\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva, C. G. d. (2020). Identifica\u0026ccedil;\u0026atilde;o da fauna parasit\u0026aacute;ria de tartarugas-marinhas encalhadas ao norte do sudoeste atl\u0026acirc;ntico, brasil.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTandon, V., \u0026amp; Gupta, N. (1981). On \u003cem\u003eDeuterobaris intestinalis\u003c/em\u003e Mehrotra, 1973 and \u003cem\u003eOctangium takanoi\u003c/em\u003e Kobayashi, 1921 (Trematoda: Microscaphidiidae) from a marine turtle in India. \u003cem\u003eProceedings: Animal Sciences\u003c/em\u003e, \u003cem\u003e90\u003c/em\u003e, 553\u0026ndash;560.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVan Cleave, H. J., \u0026amp; Ross, J. A. (1947). Use of trisodium phosphate in microscopical technic. \u003cem\u003eScience\u003c/em\u003e, \u003cem\u003e106\u003c/em\u003e(2748), 194\u0026ndash;194.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVaughan, H. F. (1924). \"The death of Arthur Looss\". \u003cem\u003eAmerican Journal of Public Health\u003c/em\u003e, \u003cem\u003e13\u003c/em\u003e ((8)), 659. doi:610.2105/AJPH.2113.2108.2659.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWood, C. L., \u0026amp; Vanhove, M. P. (2023). Is the world wormier than it used to be? We'll never know without natural history collections. \u003cem\u003eJournal of Animal Ecology\u003c/em\u003e, \u003cem\u003e92\u003c/em\u003e(2), 250\u0026ndash;262.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWoRMS. (2023). \u003cem\u003eOctangium Looss, 1902. Accessed at: https://marinespecies.org/aphia.php?p=taxdetails\u0026amp;id=725391 on 2023-09-19\u003c/em\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWyneken, J., Lohmann, K. J., \u0026amp; Musick, J. A. (2013). \u003cem\u003eThe Biology of Sea Turtles, Volume III\u003c/em\u003e. CRC Press. https://books.google.se/books?id=Xf_RBQAAQBAJ\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamaguti, S. (1958). 'Systema Helminthum. 1. The Digenetic Trematodes of Vertebrates.' Vol. 1. (Interscience Publishers, New York.).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamaguti, S. (1971). \u003cem\u003eSynopsis of the digenetic trematodes of vertebrates. Vol. 1, 1074 pp, Vol. II, 349 plates\u003c/em\u003e Keigaku.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"c5069b12-f914-41ce-8bcc-cb393c825bb0","identifier":"10.13039/501100004360","name":"Sveriges Lantbruksuniversitet","awardNumber":"dha 2019.4.3-48","order_by":0}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Naturhistoriska riksmuseet","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":"Octangium, Chelonia mydas, Arthur Looss, Collection, Naturhistoriska riksmuseet, Egypt","lastPublishedDoi":"10.21203/rs.3.rs-5018739/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5018739/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cem\u003eOctangium\u003c/em\u003e Looss, 1902 is a taxonomically challenging genus of microscaphidiid trematodes, with members harmful at the adult stage to their reptile hosts, the turtles. In Arthur Loss\u0026rsquo;s collection preserved at the Swedish Museum of Natural History, we found mounted slides of \u003cem\u003eO. sagitta\u003c/em\u003e (Looss, 1899) and of \u003cem\u003eO. hasta\u003c/em\u003e Looss, 1902, and vials containing \u003cem\u003eOctangium\u003c/em\u003e spp. preserved in ethanol from a host and locality matching those listed in Looss (1899), suggesting that this is the part of type material. Unfortunately, several specimens were dried. We attempted herein to rehydrate them, make whole stained mounts, and investigate the material.\u003c/p\u003e \u003cp\u003eAdditionally, we examined several specimens of \u003cem\u003eO. sagitta\u003c/em\u003e and \u003cem\u003eO. hasta\u003c/em\u003e from the Invertebrate collections at the SMNH and provided illustrated redescriptions. In light of the available data, also discuss records of \u003cem\u003eO. sagitta\u003c/em\u003e, \u003cem\u003eO. hasta\u003c/em\u003e, and previous species synonymized with \u003cem\u003eO. sagitta\u003c/em\u003e and provide a key for the identification of \u003cem\u003eOctangium\u003c/em\u003e spp. We herein reinstate \u003cem\u003eOctangium takanoi\u003c/em\u003e Kobayashi, 1921 and \u003cem\u003eO. hasta\u003c/em\u003e, and amend \u003cem\u003eOctangium\u003c/em\u003e based on a re-examination of adult specimens of the type material of \u003cem\u003eO. sagitta\u003c/em\u003e [type species] and of \u003cem\u003eO. hasta\u003c/em\u003e, infecting the intestine of the green sea turtle \u003cem\u003eChelonia mydas\u003c/em\u003e. We demonstrate that \u003cem\u003eO. takanoi\u003c/em\u003e differs from \u003cem\u003eO. sagitta\u003c/em\u003e by being twice smaller, by the shape of the oral sucker (rectangular \u003cem\u003evs\u003c/em\u003e. rounded), and especially by the extent of vitellaria, with their anterior end situated at the level of the anterior margin of the testes in \u003cem\u003eO. takanoi\u003c/em\u003e, while they extend to the intestinal bifurcation in \u003cem\u003eO. sagitta\u003c/em\u003e. Additionally, they can be easily distinguished by more anterior placing of the testes in \u003cem\u003eO. takanoi\u003c/em\u003e. Similarly, \u003cem\u003eO. hasta\u003c/em\u003e can be easily distinguished from \u003cem\u003eO. sagitta\u003c/em\u003e by being significantly smaller in all body measurements. More importantly, \u003cem\u003eO. sagitta\u003c/em\u003e and \u003cem\u003eO. hasta\u003c/em\u003e can be easily distinguished by the shape of the oral sucker. We refute thus the synonymies between \u003cem\u003eO. sagitta\u003c/em\u003e and the two species \u003cem\u003eO. takanoi\u003c/em\u003e and \u003cem\u003eO. hasta\u003c/em\u003e, and we reinstate the two latter species as valid species. We summarized and mapped the distribution of current valid species of the genus \u003cem\u003eOctangium\u003c/em\u003e.\u003c/p\u003e","manuscriptTitle":"“Reviving museum oddities: rehydrating Trematodes curiosities!” A successful method for rehydrating dried museum specimens for a revision of the genus Octangium (Trematoda), parasites of green sea turtle Chelonia mydas","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-04 16:00:11","doi":"10.21203/rs.3.rs-5018739/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":"05e2d78f-1c80-4395-95c4-4b0990f40167","owner":[],"postedDate":"September 4th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":36967870,"name":"Parasitology"}],"tags":[],"updatedAt":"2024-09-04T16:00:12+00:00","versionOfRecord":[],"versionCreatedAt":"2024-09-04 16:00:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5018739","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5018739","identity":"rs-5018739","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}