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THALATTOSUCHUS SUPERCILIOSUS (BLAINVILLE IN EUDES- DESLONGCHAMPS, 1852) GEN. & COMB. NOV. (FIG. 6) v 1808 Espèce inconnue de crocodile – Cuvier, pp. 90–92, pl. 11, figs 1, 2. [partim] v 1824 Tête à museau plus court – Cuvier, pp. 152–153, pl. 8, figs 1, 2. [partim] v 1825 Steneosaurus rostro -minor [sic] sp. nov. – Geoffroy Saint-Hilaire, pp. 147, 149. [nomen oblitum] v 1832 Streptospondylus altfordensis sp. nov. – von Meyer, p. 106. [partim] Table 6 Continued e, Estimate. * The anterior four alveoli of MNHN.F RJN 116 are not preserved. v 1837 Metriorhynchus geoffroyi [sic] von Meyer – Bronn, 1835 –37, p. 520, pl. 26, fig. 7b [partim] v* 1852 Crocodilus superciliosus sp. nov. – Blainville in J.-A. Eudes-Deslongchamps, p. 114. v 1863 Teleosaurus superciliosus (Blainville) comb. nov. – J.-A. Eudes-Deslongchamps, p. 8. v 1867 Teleosaurus superciliosus (Blainville) – J.-A. Eudes- Deslongchamps, pp. 20–21. v 1867 Teleosaurus blainvillei sp. nov. – J.-A. Eudes- Deslongchamps, pp. 19–20. v 1869 Metriorhynchus superciliosus (Blainville) comb.nov. – Eudes- Deslongchamps,1867–69, p. 306, pl. 20, fig.2, pl. 21, fig. 1. v 1869 Metriorhynchus blainvillei (E-Deslongchamps) comb. nov. – Eudes-Deslongchamps, 1867 –69, p. 295, pl. 20 fig. 1, pl. 21, figs 2, 3. v 1869 Metriorhynchus moreli sp. nov. – Eudes-Deslongchamps, 1867 –69, p. 320, pl. 21, figs 4, 5, pl. 22, figs 1, 2. v 1869 Steneosaurus dasyceps sp. nov. – Seeley, p. 140. v 1890 b Metriorhynchus superciliosum (Blainville) unjust. emend. – Lydekker, p. 232. v 1904 Metriorhynchus jaekeli sp. nov. – Schmidt, p. 97, pls 11, 12. v 1973 Metriorhynchus superciliosum [sic] (Blainville) – Steel, p. 45, figs 18 (7, 9), 19 (7). v 1973 Metriorhynchus blainvillei (Eudes-Deslongchamps) – Steel, p. 46, fig. 19 (2). v 1973 Metriorhynchus moreli (Eudes-Deslongchamps) – Steel, p. 46, fig. 19 (1). v 2009 Metriorhynchus moreli (Eudes-Deslongchamps) – Young & Andrade, p. 566. v 2009 Metriorhynchus superciliosus (Blainville) – Young & Andrade, p. 566. v 2010 Metriorhynchus superciliosus (Blainville) – Young et al., p. 804, figs 4, 6, 8. v 2018 Metriorhynchus superciliosus (Blainville) – Brignon, pp. 56–61, fig. 11. Lectotype: MNHN.F.RJN 256, incomplete skull. (Designation by Eudes-Deslongchamps, 1867 –69: 310). Note: Young et al. (2013) followed Vignaud (1995) in calling MNHN.F. RJN 256 (formerly MNHN 8903) the neotype. As shown by Brignon (2018a), it is in fact the lectotype. Type locality: Vaches Noires cliffs, Département du Calvados, Basse-Normandie, France. Type horizon: Either the Marnes de Dives Formation or Marnes de Villers Formation. Either upper Callovian or lower Oxfordian, Middle or Upper Jurassic. Occurrence: Callovian/Oxfordian of northern France and England (UK). LSID Zoobank registration: urn: lsid: zoobank. org:act: 151309F9-ED14-43C6-A00F-6BFFED2DD3A2 Etymology: The genus is derived from the Greek θάλαττα, sea, and σοῦχος crocodile (after the Egyptian crocodile god). The species name derives from Latin, the prefix super-, above, and ciliosus, with eyelashes, referring to the expanded prefrontals above the orbits. Diagnosis: Metriorhynchid crocodylomorph with the following unique combination of characters: conical teeth with little mediolateral compression, crowns have a continuous smooth keel at mesial and distal edges (lacks serrations), enamel on labial and lingual surfaces have conspicuous ornamentation composed of accessory ridges orientated to the apicobasal axis of the crown. Enamel ornamentation is stronger on the lingual face than on the labial face. Dental formula: three premaxillary pairs; 23–27 maxillary pairs, of which 14–15 are anterior to the palatines; 20–22 dentary pairs, of which 16–17 are adjacent to the symphyseal suture and nine to ten are anterior to the splenials. Premaxillary alveoli are consistent in size, with the P1 and P3 being more oval in shape, with the P2 being more subcircular. The skull is narrow with a mesorostrine snout (sensu Young et al. 2010). No transverse expansion of the premaxilla (only present in dorsoventrally crushed specimens). Little to no constriction at the premaxilla–maxilla contact. Nasals and premaxillae always separated; in specimens with a basicranial length of 600 mm or more, the distance between the nasals and premaxillae range from 50 to 132 mm. The nasals terminate anteriorly level to the M9-to-M12 alveoli. Both the frontal and prefrontal bones have a conspicuous pitted ornamentation, although the expression of frontal ornamentation is highly variable. Approximately 90-degree angle formed by the lateral and medial processes of the frontal, with the rostromedial border of the frontoparietal fossa being either rounded or forming a right angle (variability most likely due to taphonomic distortion). A thin sclerotic ring composed of seven ossicles, which do not fill the entire orbit. The deltopectoral crest is moderately developed, with the width of the humerus distal articular head being greater than the width of the deltopectoral crest projecting out from the humerus shaft. (Modified from Young et al., 2013.) Referred specimens AMNH FR 997: Incomplete skull with mandible, and 23 assorted vertebrae (including cervicals and dorsals); CAMSM J64398: skull (holotype of Steneosaurus dasyceps); CAMSM J64900: midportion of skull; CAMSM J64918: rostrum; GLAHM V 942: skull with mandible from a young individual; GLAHM V 963: incomplete skull and mandible, eight dorsal vertebrae, one caudal vertebra, both coracoids, left scapula, right ilium, left ischium and right ischium blade, distal half of the right pubis (from a young individual); GLAHM V 964: skull, mandible, atlas–axis, four cervical vertebrae, cervical and dorsal ribs; GLAHM V 965: skull with right dentary; GLAHM V 971: skull in various fragments, atlas–axis, five cervical vertebrae, ten dorsal vertebrae; GLAHM V 982: broken skull, mandible, cervical vertebra centrum, atlas left rib; GLAHM V 983: broken skull, mandible, sclerotic ring ossicles, dorsal rib; GLAHM V 984: broken skull and mandible fragments from two individuals; GLAHM V 985: broken skull and mandible fragments, sclerotic ring ossicles; GLAHM V 987: broken skull and mandible fragments, sclerotic ring ossicles, rib fragments; GLAHM V 988: skull, mandible, atlas–axis, one dorsal vertebra, left ilium, fragment of right pubis, right femur; GLAHM V 989: skull with mandible; GLAHM V 996: skull with bite marks consistent with that of a metriorhynchid; GLAHM V 1004: skull and mandible fragments, atlas–axis; GLAHM V 1015: incomplete skull, disarticulated mandible, atlas–axis, right atlas rib, both coracoids, right ischium, femora, right tibia and fibula, two coprolites; GLAHM V 1027: incomplete skull and mandible, atlas–axis, four cervical vertebrae (from a young individual); GLAHM V 1140: broken skull, mandible showing pathological damage, one hyoid, atlas–axis, five cervical vertebrae, 14 dorsal vertebrae, scapulae, both coracoids, humeri, both radii, femora; GLAHM V 1142: skull, disarticulated mandible, one hyoid, atlas–axis, right atlas rib, four cervical vertebrae, 19 dorsal vertebrae, two sacral vertebrae, four caudal vertebrae, pubes, ilia, ischia – fused, femora; GLAHM V 1143: skull broken in two, mandible, atlas ribs, five cervical vertebrae, four cervical ribs, 17 dorsal vertebrae, right scapula, right coracoid, right humerus (atlas–axis and forelimb lost); MGCL 9959: skull, mandible, associated dorsal and caudal vertebrae, humerus, femur; MGCL 9960: skull, mandible, associated cervical, dorsal and caudal vertebrae, isolated ribs, humerus, pubis, ischium, femur; MNHN.F RJN 116: lower jaw (lectotype of Steneosaurus rostrominor, nomen oblitum); NHMUK PV R 1530: incomplete skull with mandible, atlas–axis, five cervical vertebrae, 16 dorsal vertebrae, two sacral vertebrae, 35 caudal vertebrae, cervical and dorsal ribs, coracoid, scapula, humeri, ilia, ischia, pubes, femora, tibiae, fibulae, isolated pes bones, numerous chevrons; NHMUK PV R 1529: skull and mandible (from a young individual); NHMUK PV R 1666: skull and mandible; NHMUK PV R 2030: incomplete skull with mandible; NHMUK PV R 2032: incomplete skull and mandible, atlas–axis, four cervical vertebrae, 17 dorsal vertebrae, two sacral vertebrae, 37 caudal vertebrae, cervical and dorsal ribs, scapula, coracoids, humerus, ilium, ischium, femur; NHMUK PV R 2033: fragmentary skull with mandible, atlas–axis, five cervical vertebrae, 17 dorsal vertebrae, two sacral vertebrae, 29 caudal vertebrae, cervical and dorsal ribs, ilia – fused, ischia – fused, pubes, one tibia, one fibula, two metatarsals; NHMUK PV R 2036: fragments of skull and mandible, one cervical vertebra; NHMUK PV R 2041: incomplete skull; NHMUK PV R 2044: skull and mandible; NHMUK PV R 2049: incomplete skull and mandible, two dorsal vertebrae, one sacral vertebra, ilia, ischia, femora, tibiae, fibulae, isolated bones of the pes; NHMUK PV R 2051: incomplete skull with mandible, atlas–axis, four cervical vertebrae, 15 dorsal vertebrae, two sacral vertebrae, 32 caudal vertebrae, coracoid, scapula, ilia, ischia, pubes, femora, broken tibiae and fibulae, isolated pes bones; NHMUK PV R 2053: incomplete skull; NHMUK PV R 2054: skull, mandible, atlas–axis, four cervical vertebrae, 18 dorsal vertebrae, two sacral vertebrae, 28 caudal vertebrae, cervical and dorsal ribs, ilium, ischium, pubes, tibia, fibula, isolated pes bones, numerous chevrons; NHMUK PV R 2055: incomplete skull; NHMUK PV R 2056: fragments of skull and mandible (from a young individual); NHMUK PV R 2058: skull with mandibular symphysis; NHMUK PV R 2065: skull fragments (from a young individual); NHMUK PV R 2069: fragments of skull and mandible, atlas–axis, three cervical vertebrae (from a young individual); NHMUK PV R 3016: incomplete skull, mandible, right coracoid, scapulae, humeri, radius, ulna; NHMUK PV R 6859: skull with disarticulated mandible; NHMUK PV R 6860: skull with disarticulated mandible; PETMG R8: skull lacking rostrum; PETMG R10: incomplete skull; PETMG R20: incomplete skull; PETMG R42: incomplete skull; PETMG R180: incomplete skull; SMNS 10115: skull with disarticulated mandible; SMNS 10116: skull with disarticulated mandible. Note: The possibility that Thalattosuchus superciliosus is a species-complex and that the epithets moreli or blainvillei could represent cryptic species is not investigated. That is beyond the scope of this contribution and will be examined in future studies., Published as part of Young, Mark T., Brignon, Arnaud, Sachs, Sven, Hornung, Jahn J., Foffa, Davide, Kitson, James J. N., Johnson, Michela M. & Steel, Lorna, 2021, Cutting the Gordian knot: a historical and taxonomic revision of the Jurassic crocodylomorph Metriorhynchus, pp. 510-553 in Zoological Journal of the Linnean Society 192 (2) on pages 538-543, DOI: 10.1093/zoolinnean/zlaa092, http://zenodo.org/record/7017003, {"references":["Bronn HG. 1835 - 1837. Lethaea geognostica: Bd. 1 Das Ubergangs- bis Oolithen-Gebirge. Stuttgart: E. Schweizerbart, 544.","Eudes-Deslongchamps J-A. 1867. [posthumous work] Note sur les teleosauriens. Caen: Le Blanc-Hardel.","Young MT, Andrade MB, Brusatte SL, Sakamoto M, Liston J. 2013. The oldest known metriorhynchid superpredator: a new genus and species from the Middle Jurassic of England, with implications for serration and mandibular evolution in predacious clades. Journal of Systematic Palaeontology 11: 475 - 513.","Vignaud P. 1995. Les Thalattosuchia, crocodiles marins du Mesozoique: Systematique, phylogenie, paleoecologie, biochronologie et implications paleogeographiques. Unpublished Ph. D. thesis, Universite de Poitiers, France.","Brignon A. 2018 a. Contexte historique de la collection Felix de Roissy (1771 - 1843) de reptiles marins jurassiques des Vaches Noires. Geodiversitas 40: 43 - 68.","Young MT, Brusatte SL, Ruta M, Andrade MB. 2010. The evolution of Metriorhynchoidea (Mesoeucrocodylia: Thalattosuchia): an integrated approach using geometrics morphometrics, analysis of disparity and biomechanics. Zoological Journal of the Linnean Society 158: 801 - 859."]}

THALATTOSUCHUS GEN. NOV. (FIG. 6) Type species Crocodilus superciliosus Blainville in Eudes- Deslongchamps, 1852 (following Recommendation 67B of the ICZN Code) (nomen protectum). Now referred to as Thalattosuchus superciliosus (Blainville in Eudes- Deslongchamps, 1852) comb. nov. Type by designation. Thalattosuchus superciliosus is a junior subjective synonym of Steneosaurus rostrominor Geoffroy Saint- Hilaire, 1825 (nomen oblitum). Etymology ‘Sea crocodile’, given that the species superciliosus is perhaps the best-known thalattosuchian, it is fitting that the genus be established for this species. Diagnosis Same as the only species (see below).

METRIORHYNCHUS BREVIROSTRIS (HOLL, 1829) (FIGS 1–3) v 1820 Upper jaw of the fossil crocodile from Havre in the Museum of the Academy of Geneva – De la Beche, lithograph. v 1824 Tête à museau plus court [partim] – Cuvier, pp. 152– 153, pl. 10, figs 5–7. v* 1829 Steneosaurus brevirostris sp. nov. – Holl, p. 88. v* 1831 Gavialis Jurinii sp. nov. – Gray, p. 57. [sic] [partim] v* 1832 Metriorhynchus geoffroyii gen. et sp. nov. – von Meyer, p. 106. [partim] v 1836 Anterior extremity of the upper jaw of Steneosaurus – Buckland, p. 36, pl. 25’ fig. 3. v 1837 Metriorhynchus Geoffroyii (von Meyer) – Bronn, p. 520, pl. 26, figs 7b,d, 8a,b. [sic] [partim] v 1845 Steneosaurus rostro-minor [sic] Geoffroy Saint-Hilaire – Pictet, p. 46, pl. 1, fig. 2 [partim] v 1853 Steneosaurus rostro-minor [sic] Geoffroy Saint-Hilaire – Pictet, p. 492–493, pl. 25, fig. 9 [partim] v 1973 Metriorhynchus geoffroyi (von Meyer) – Steel., p. 45, fig. 18 (10). [sic] v 1987 Metriorhynchus geoffroyi (von Meyer) – Adams- Tresman, p. 193. [sic] v 2010 Metriorhynchus geoffroyii (von Meyer) – Young et al., p. 803. Holotype: MHNG V-2232, partial cranial rostrum. Casts of holotype: MGCL 9868, PIMUZ A/III 82 and OUMNH unnumbered. Type locality and horizon: Le Havre, Département de Seine-Maritime, Haute-Normandie, France. Kimmeridgian, Upper Jurassic. Etymology: From Latin brevis, short, and rostrum, snout. The combination with the genus results in ‘the short snouted moderate snout’ (or ‘moderate short snout’), which is perhaps unfortunate. Diagnosis: Metriorhynchid crocodylomorph with the following unique combination of characters: premaxilla posterodorsal processes terminate level to the M3 alveoli; the three premaxillary alveoli successively increase in size, with the P1 alveoli being circular in shape and the P3 alveoli being the most oval of the premaxillary tooth-row; premaxilla is transversely broad level to the narial fossa posterior margin; constriction at the premaxilla–maxilla contact; having at least 13 maxillary alveoli anterior to the palatine anterior processes; maxillary alveoli M1–M13 are irregularly shaped ovals, with the post-M3 alveoli becoming more circular in shape; nasal anterior processes terminate level to the M8 alveoli; lacks a fully ossified internarial bar (thus an undivided external naris); the anterior-margin of the narial fossa is posterior to the P1 alveoli and the posterior margin terminates slightly posterior to the premaxillary tooth-row. Description The holotype of Metriorhynchus brevirostris (MHNG V-2232; Figs 1–3) is the cranial rostrum, preserving the premaxilla, maxilla and the anterior process of the nasals. In palatal view only, the premaxilla and maxilla are preserved, and there are no complete tooth crowns. Overall, the snout is long and narrow, with a slightly concave upper margin (Figs 1, 2). In dorsal view, widest part of the premaxillae is slightly wider than the anterior portion of the maxillae. Premaxilla and external nares: In dorsal view, the premaxilla is an anteroposteriorly elongated rhomboid (Fig. 1). The premaxillary posterodorsal processes are not particularly elongated for a metriorhynchid, terminating approximately level to the third (M3) maxillary alveoli. The suture between the premaxilla and maxilla is not entirely clear, but it appears to be almost straight (rather than curved or strongly interdigitating), with the posterodorsal processes converging posteriorly. The premaxilla only contacts the maxilla along its posterior margins. In lateral view, the external surfaces are slightly convex (Fig. 2). The ornamentation on the external surfaces is hard to discern due to encrustations. The external naris aperture is largely circular, undivided and situated within the larger narial fossa (Figs 1–3). The shape of the narial fossa is unclear, due to the poor preservation of the anterior margin, but it looks to have been oval-shaped. There is no evidence of an ossified narial bar, but the posterior-end of the bar is preserved, slightly overhanging the external naris. The anterior-margin of the narial fossa is posterior to the P1 alveoli, while the posterior-margin of the narial fossa is slightly posterior to the premaxillary tooth-row. In palatal view, three widely spaced alveoli can be seen (Fig. 1B). The first alveoli (P1) are the smallest and are circular in shape. The P2 alveoli are larger and more oval in shape, while the P3 alveoli are the largest in the premaxilla and are oval in shape. The premaxilla–maxilla contact is an anteriorly directed ‘V’-shape created by the maxilla palatal anterior process overlapping the premaxilla. The maxillary palatal process terminates level to the anterior margin of the P3 alveoli. It appears as though the incisive foramen is positioned medial to the P2 alveoli but, given the preservation of the rostrum, this is not entirely clear. The palatal processes of the premaxilla form the anterior margin of the M1 alveolar margin. Maxilla: Approximately the anterior half of the maxilla is preserved (Fig. 1). The external surfaces of the maxillae are slightly convex. The ornamentation is difficult to distinguish from the encrustations, but along the alveolar margins on the right side, there appears to be natural external surface texture (Fig. 2B). It is composed of well-developed anteroposteriorly aligned ridges, suggesting that the rostrum may have been ornamented in life. In Tyrannoneustes lythrodectikos (Foffa &Young, 2014) and Dakosaurus maximus (Young et al., 2012) there are clear shifts in ornamentation patterns across the maxilla; given the preservation of the holotype we cannot determine if that is true for Metriorhynchus brevirostris. In lateral view, the preservation of the specimen precludes us from determining of there were reception pits on the lateral margins of the maxillae (Fig. 2). In palatal view, 12 alveoli are preserved on the right maxilla (anterior section of the 13 th alveolus is visible), while there are 13 complete alveoli on the left maxilla (with the anterior section of the 14 th alveolus visible) (Fig. 1). All alveoli are circular to subcircular in shape. The interalveolar spaces are variable in size. The M1 and M2 alveoli are closely packed, from M2 to M7 the interalveolar spaces are wider, between M7 and M8 there is the largest preserved gap, M8–M10 has gaps similar in size to those of M2–M7; finally, from M10 posteriorly the interalveolar spaces become small. Paired palatal grooves are present on either side of the maxilla midline. The grooves appear to terminate level to the M5 alveoli. In Ty. lythrodectikos these grooves terminate level to the M4 alveoli (Foffa & Young, 2014), and in the ‘English rostrum’ from the ‘E-clade’ these grooves continue anteriorly along maxilla terminating level to the M2 alveoli (Young et al., 2020a). Nasals: Little of the nasals are preserved,only the anterior processes. The anterior processes form the characteristic converging triangular shape seen in thalattosuchians (e.g. see Fraas, 1902; Andrews, 1913) (Fig. 1). The nasals are paired, with the anterior processes terminating level to the M8 alveoli. Due to the encrustations the ornamentation is hard to discern, but the external surface has anteroposteriorly aligned grooves., Published as part of Young, Mark T., Brignon, Arnaud, Sachs, Sven, Hornung, Jahn J., Foffa, Davide, Kitson, James J. N., Johnson, Michela M. & Steel, Lorna, 2021, Cutting the Gordian knot: a historical and taxonomic revision of the Jurassic crocodylomorph Metriorhynchus, pp. 510-553 in Zoological Journal of the Linnean Society 192 (2) on pages 531-533, DOI: 10.1093/zoolinnean/zlaa092, http://zenodo.org/record/7017003, {"references":["Holl F. 1829. Handbuch der Petrefactenkunde Teil 1. Dresden: Hilscher, 416.","Foffa D, Young MT. 2014. The cranial osteology of Tyrannoneustes lythrodectikos (Crocodylomorpha: Metriorhynchidae) from the Middle Jurassic of Europe. PeerJ 2: e 608.","Young MT, Brusatte SL, Andrade MB, Desojo JB, Beatty BL, Steel L, Fernandez MS, Sakamoto M, Ruiz- Omenaca JI, Schoch RR. 2012. The cranial osteology and feeding ecology of the metriorhynchid crocodylomorph genera Dakosaurus and Plesiosuchus from the Late Jurassic of Europe. PLoS One 7: e 44985.","Young MT, Sachs S, Abel P, Foffa D, Herrera Y, Kitson JJN. 2020 a. Convergent evolution and possible constraint in the posterodorsal retractions of the external nares in pelagic crocodylomorphs. Zoological Journal of the Linnean Society 189: 494 - 520.","Fraas E. 1902. Die Meer-Krocodilier (Thalattosuchia) des oberen Jura unter specieller Berucksichtigung von Dacosaurus und Geosaurus. Palaeontographica 49: 1 - 72.","Andrews CW. 1913. A descriptive catalogue of the marine reptiles of the Oxford Clay, Part Two. London: British Museum (Natural History)."]}