Metriorhynchus

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Metriorhynchus
Temporal range: Kimmeridgian,
157–150  Ma
Metriorhynchus brevirostris.jpg
Partial holotype rostrum (MHNG V-2232) of M. brevirostris as illustrated in 1824
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Suborder:† Thalattosuchia
Family:† Metriorhynchidae
Genus:† Metriorhynchus
von Meyer, 1832 [1]
Species:
†M. brevirostris
Binomial name
†Metriorhynchus brevirostris
(Holl, 1828) vide Young et al., 2020 [2]
Synonyms

Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Late Jurassic. The type species, M. brevirostris was named in 1829 as a species of Steneosaurus before being named as a separate genus by the German palaeontologist Christian von Meyer in 1832. [1] The name Metriorhynchus means "moderate snout", and is derived from the Greek Metrio- ("moderate") and -rhynchos ("snout").

Contents

Discovery and species

Fossil specimens referrable to Metriorhynchus are known from Kimmeridgian (Late Jurassic) deposits of France. [2]

The earliest discovered specimen of Metriorhynchus brevirostris is MNHN.F.RJN 116, a jaw collected from the Marnes de Villers by Charles Bacheley during the early 1770s, who believed it belonged to a fish in 1778 and then a dolphin or a sperm whale in 1808, [3] [4] that was described by Cuvier (1808). [5] The holotype of M. brevirostris is MHNG V02232, a partial rostrum from Le Havre, and Georges Cuvier mentioned that it was in the collection of the Museum of the Academy of Geneva in 1811. [6] In 1824, Cuvier then described multiple "gavial" remains and came to the now-incorrect conclusion that he was describing two species (what would later become Metriorhynchus and Streptospondylus ); [6] Cuvier had also grouped into the remains the lectotype of Steneosaurus rostromajor . [2]

When naming Steneosaurus in 1825, Étienne Geoffroy Saint-Hilaire created two species for the genus: Steneosaurus rostro-major (now S. rostromajor) and S. rostro-minor. [7] He assigned MNHN.F.RJN 116 to S. rostro-major and Friedrich Holl created Steneosaurus brevirostris in 1829 to solely classify MHNG V02232. [8] In 1831, John Edward Gray instead assigned the specimen to the gharial species Gavialis jurinii. [9] The next year, Hermann von Meyer separated Cuvier's two "gharial" species and created Metriorhynchus brevirostris, Metriorhynchus geoffroyi (to house MHNG V02232) and Streptospondylus altdorfensis (now recognised as a theropod dinosaur). [1] Amongst the splitting of the "gavial" species, von Meyer (1832) incorrectly placed MNHN.F.RJN 116 within S. altdorfensis. [2]

François Jules Pictet suggested that Metriorhynchus was a synonym of Steneosaurus and in 1845 was the first author to invalidate S. rostro-minor as a species. [10] Metriorhynchus as a genus was later reinstated, and Eugène Eudes-Deslongchamps (1867–69) recognized four Callovian species of Metriorhynchus: M. superciliosus, M. moreli, M. blainvillei, and M. brachyrhynchus, [11] and he also standardised the use of the genus name Metriorhynchus. [2]

Richard Lydekker in 1888a suggested it to be "advisable" to retain the name Metriorhynchus, [12] and in 1889a he suggested that Metriorhynchus was similar to Cricosaurus and therefore he concluded the genus was crocodilian. [13] Steel moved MHNG V02232 back into Metriorhynchus geoffroyii in 1973.

Young et al. (2010) was the first to restrict M. brevirostris by re-assigning specimens to other genera, [14] and MHNG V02232 was designated as the holotype of M. brevirostris by Young et al. (2019). [2] Young et al. (2019) also synonymised M. geoffroyii with M. brevirostris and reassigned MNHN.F.RJN 116 to M. brevirostris. [2]

Valid species

Only one valid species is recognized today, the type species M. geoffroyii (now called M. brevirostris). [2] "Metriorhynchus" hastifer and "M." palpebrosus are generically distinct from the Metriorhynchus type species, with hastifer being recovered as a geosaurine. [15] [16] Species in this genus were traditionally classed into two skull groups: longirostrine (long, narrow jaws) and brevirostrine (short, broad jaws). However, most of brevirostrine species have been transferred to the genera Purranisaurus and Suchodus . [14] [17] Metriorhynchus superciliosus was also shown to be generically distinct from the type species, M. brevirostris, and now has its own genus Thalattosuchus . [2]

Life reconstruction of Metriorhynchus brevirostris Life reconstruction of Metriorhynchus brevirostris.png
Life reconstruction of Metriorhynchus brevirostris

The genera Purranisaurus and Suchodus have been considered junior synonyms of Metriorhynchus. [18] Recent phylogenetic analyses however, do not support the monophyly of Metriorhynchus, as believed during the 1860s-2010. [19] [20] [21] [2]

Eudes-Deslongchamps (1867–69) recognized four Callovian species of Metriorhynchus: M. superciliosus, M. moreli, M. blainvillei, and M. brachyrhynchus. [11] Later, Andrews (1913) considered there to be seven valid species: M. superciliosus, M. moreli, M. brachyrhynchus, M. durobrivensis, M. cultridens, M. leedsi and M. laeve. [22] However, Adams-Tresman (1987), using linear morphometrics, could only distinguish between the two skull groups, so she found there to be two species from the Oxford Clay, M. superciliosus and M. brachyrhynchus. [23] Vignaud (1997) however, considered there to be three Callovian species: M. superciliosus, M. brachyrhynchus and M. leedsi, [24] and a 2022 study describing a new metriorhynchid specimen advocated returning to this taxonomic system, considering Gracilineustes and Thalattosuchus junior synonyms of Metriorhynchus. [25]

Unnamed species

Fragmentary remains attributed to Metriorhynchus are known from South America during the Bajocian [26] and Bathonian (both Middle Jurassic). [27] However, phylogenetic analysis has shown that these species cannot be referred to Metriorhynchus. [14] [28] [2]

Description

Metriorhynchus was a thalattosuchian, a group of marine crocodylomorphs. It was a member of the Metriorhynchidae, a group of thalattosuchians with a tail anatomy which indicates that they had a tail fluke similar to that of a shark. Unlike many other pseudosuchians, they did not have extensive osteoderms covering the body. Instead it appears that they had smoother skin similar to other marine reptiles like plesiosaurs and ichthyosaurs. [29] Metriorhynchids also had a hip anatomy conducive for live birth and evidence from the related Dakosaurus does show that they did this. [30] Metriorhynchus can be distinguished from other metriorhynchids in that the three front teeth get bigger from front to back, with the first being round and the third more oval-shaped. The jaws have a narrow point where different parts of the upper jaw meet, and there are at least 13 teeth before the palatine bones start. The teeth are mostly oval-shaped, but after the third one, they become rounder. The front part of the nasal bones stops near the eighth tooth, and unlike most animals, it has a single large external nostril instead of two separate ones. The opening for the nostrils begins behind the first tooth and ends just past the last one in the front section of the jaw. [2] It was about 3 meters (9.8 feet) in body length. [31]

Paleoecology

Metriorhynchus was a carnivore. One fossil shows it has eaten the gill apparatus of the giant fish Leedsichthys . The idea of Metriorhynchus attacking weak Leedsichthys individuals has been speculated to be the case in the past such as in the BBC and Discovery Channel documentary Sea Monsters. [32] [33]

See also

References

  1. 1 2 3 von Meyer H. (1832). Palaeologica zur Geschichte der Erde und ihrer Geschöpfe. Frankfurt am Main: Siegmund Schmerber, 560.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 Young, Mark T; Brignon, Arnaud; Sachs, Sven; Hornung, Jahn J; Foffa, Davide; Kitson, James J N; Johnson, Michela M; Steel, Lorna (2020-11-03). "Cutting the Gordian knot: a historical and taxonomic revision of the Jurassic crocodylomorph Metriorhynchus". Zoological Journal of the Linnean Society. 192 (2): 510–553. doi:10.1093/zoolinnean/zlaa092. ISSN   0024-4082.
  3. ↑ Bacheley, C. (1778) Notice des pétrifications & autres faits d’histoire naturelle qui se trouvent le long [des] côtes du Pays d’Auge. In: Lépecq de la Clôture, L. Collection d’observations sur les maladies et constitutions épidémiques. Rouen: Imprimerie privilégiée, pp. 357–359.
  4. ↑ Brignon, A. (2016) Abbé Bacheley and the discovery of the first dinosaurs and marine crocodilians from the Jurassic of the Vaches Noires (Callovian/Oxfordian, Normandy, France). Comptes Rendus Palevol15 : 595–605 (in French with an abridged English version).
  5. ↑ Cuvier, G. (1808). Sur les ossemens fossiles de crocodiles, et particulièrement sur ceux des environs du Havre et de Honfleur, avec des remarques sur les squelettes des sauriens de la Thuringe. Annales du Muséum d’Histoire Naturelle 12: 73–110, pl. 10–11.
  6. 1 2 Cuvier, G. (1824). Recherches sur les ossemens fossiles, où l’on rétablit les caractères de plusieurs animaux dont les révolutions du globe ont détruit les espèces, nouvelle édition, 2e partie, Vol. 5. Paris: G. Dufour et E. d’Ocagne.
  7. ↑ Geoffroy Saint-Hilaire, É. (1825) Recherches sur l’organisation des gavials, sur leurs affinités naturelles desquelles résulte la nécessité d’une autre distribution générique: Gavialis, Teleosaurus, Steneosaurus; et sur cette question, si les gavials (Gavialis), aujourd’hui répandus dans les parties orientales de l’Asie, descendent, par voie non interrompue de génération, des gavials antidiluviens, soit des gavials fossiles, dits crocodiles de Caen (Teleosaurus), soit des gavials fossiles du Havre et de Honfleur (Steneosaurus). Mémoires du Muséum d’Histoire Naturelle 12: 97–155, pl. 5–6.
  8. ↑ Holl, F. (1829). Handbuch der Petrefactenkunde Teil 1.Dresden: Hilscher, 416.
  9. ↑ Gray, J.E. (1831) Synopsis reptilium or short descriptions of the species of reptiles. Part I: Cataphracta, tortoises, crocodiles, and enaliosaurians. London: Treuttel, Wurz & Co., 85.
  10. ↑ Pictet, F.J. (1845). Traité élémentaire de paléontologie ou histoire naturelle des animaux fossiles considérés dans leurs rapports zoologiques et géologiques, tome 2.Paris: Langlois et Leclerq.
  11. 1 2 Eudes-Deslongchamps E. (1867-1869). Notes Paléontologiques. Caen and Paris: 320-392.
  12. ↑ Lydekker, R. (1888a). Catalogue of the fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. London: British Museum of Natural History, 309.
  13. ↑ Lydekker, R. (1889). On the remains and affinities of five genera of Mesozoic reptiles. Quarterly Journal of the Geological Society 45: 41–59.
  14. 1 2 3 Young, Mark T.; Brusatte, Stephen L.; Ruta, Marcello; De Andrade, Marco Brandalise (2010-03-30). "The evolution of Metriorhynchoidea (mesoeucrocodylia, thalattosuchia): an integrated approach using geometric morphometrics, analysis of disparity, and biomechanics". Zoological Journal of the Linnean Society. 158 (4): 801–859. doi:10.1111/j.1096-3642.2009.00571.x. ISSN   0024-4082. S2CID   84592894.
  15. ↑ Ősi, Attila; Young, Mark T.; Galácz, András; Rabi, Márton (2018-05-10). "A new large-bodied thalattosuchian crocodyliform from the Lower Jurassic (Toarcian) of Hungary, with further evidence of the mosaic acquisition of marine adaptations in Metriorhynchoidea". PeerJ. 6 e4668. doi: 10.7717/peerj.4668 . ISSN   2167-8359. PMC   5949208 . PMID   29761038.
  16. ↑ Foffa, Davide; Young, Mark; Brusatte, Stephen (2018). "Filling the Corallian gap: new information on Late Jurassic marine reptile faunas from England". Acta Palaeontologica Polonica. 63. doi: 10.4202/app.00455.2018 . hdl: 20.500.11820/729f4cac-6217-4a21-b22c-8683b38c733b . ISSN   0567-7920. S2CID   52254345.
  17. ↑ Herrera, Yanina; Gasparini, Zulma; Fernández, Marta S. (2015-02-20). "Purranisaurus potens Rusconi, an enigmatic metriorhynchid from the Late Jurassic–Early Cretaceous of the Neuquén Basin". Journal of Vertebrate Paleontology. 35 (2) e904790. Bibcode:2015JVPal..35E4790H. doi:10.1080/02724634.2014.904790. hdl: 11336/13737 . ISSN   0272-4634. S2CID   128937976.
  18. ↑ Steel R. 1973. Crocodylia. Handbuch der Paläoherpetologie, Teil 16. Stuttgart: Gustav Fischer Verlag,116 pp.
  19. ↑ Young MT. 2007. The evolution and interrelationships of Metriorhynchidae (Crocodyliformes, Thalattosuchia). Journal of Vertebrate Paleontology27 (3): 170A.
  20. ↑ Gasparini, Zulma; Pol, Diego; Spalletti, Luis A. (2006-01-06). "An Unusual Marine Crocodyliform from the Jurassic-Cretaceous Boundary of Patagonia". Science. 311 (5757): 70–73. Bibcode:2006Sci...311...70G. doi: 10.1126/science.1120803 . hdl: 11336/73480 . ISSN   0036-8075. PMID   16282526. S2CID   10312971.
  21. ↑ Wilkinson, Laura E.; Young, Mark T.; Benton, Michael J. (2008-11-19). "A New Metriorhynchid Crocodilian (Mesoeucrocodylia: Thalattosuchia) from the Kimmeridgian (Upper Jurassic) of Wiltshire, UK" . Palaeontology. 51 (6): 1307–1333. Bibcode:2008Palgy..51.1307W. doi:10.1111/j.1475-4983.2008.00818.x. ISSN   0031-0239. S2CID   84517228.
  22. ↑ Andrews CW. 1913. A descriptive catalogue of the marine reptiles of the Oxford Clay, Part Two. London: British Museum (Natural History), 206 pp.
  23. ↑ Adams-Tresman SM. 1987. The Callovian (Middle Jurassic) marine crocodile Metriorhynchus from Central England. Palaeontology30 (1): 179-194.
  24. ↑ Vignaud P. (1997). La morphologie dentaire des Thalattosuchia (Crocodylia, Mesosuchia). Palaeovertebrata26: 35-59.
  25. ↑ Le Mort, Jonas; Martin, Jeremy E.; Picot, Laurent; Hua, Stéphane (2022-07-01). "First description of the most complete Metriorhynchus aff. superciliosus (Thalattosuchia) specimen from the Callovian of the Vaches-Noires cliffs (Normandy, France) and limitations in the classification of Metriorhynchidae". Annales de Paléontologie. 108 (3) 102539. Bibcode:2022AnPal.10802539L. doi:10.1016/j.annpal.2022.102539. ISSN   0753-3969. S2CID   254175334.
  26. ↑ Gasparini, Zulma; Vignaud, Patrick; Chong, Guillermo (2000-11-01). "The Jurassic Thalattosuchia (Crocodyliformes) of Chile; a paleobiogeographic approach". Bulletin de la Société Géologique de France. 171 (6): 657–664. doi:10.2113/171.6.657. ISSN   1777-5817.
  27. ↑ Gasparini, Zulma; Cichowolski, Marcela; Lazo, Dario G. (July 2005). "First Record of Metriorhynchus (Reptilia: Crocodyliformes) in the Bathonian (Middle Jurassic) of the Eastern Pacific". Journal of Paleontology. 79 (4): 801–805. doi:10.1666/0022-3360(2005)079[0801:fromrc]2.0.co;2. ISSN   0022-3360. JSTOR   4095052. S2CID   130493042.
  28. ↑ Young, Mark Thomas; De Andrade, Marco Brandalise (2009-10-26). "What is Geosaurus? Redescription of Geosaurus giganteus (Thalattosuchia: Metriorhynchidae) from the Upper Jurassic of Bayern, Germany". Zoological Journal of the Linnean Society. 157 (3): 551–585. doi: 10.1111/j.1096-3642.2009.00536.x . ISSN   0024-4082. S2CID   83242976.
  29. ↑ Altmühltal~mail@frederik-spindler.de, Frederik Spindler~Dinosaurier Museum; Paleontology~rene@lauerfoundationpse.org, René Lauer~Lauer Foundation for; Eichstätt~htischlinger@online.de, Helmut Tischlinger~Germany and Jura-Museum; Bayerns~maeuser@snsb.de, Matthias Mäuser~Staatliche Naturwissenschaftliche Sammlungen (2021-07-03). "The integument of pelagic crocodylomorphs (Thalattosuchia: Metriorhynchidae)". Palaeontologia Electronica. doi: 10.26879/1099 . Retrieved 2024-08-05.
  30. ↑ Spindler, Frederik (2019). Live Birth in a Jurassic Marine Crocodile [abstract]. In: Abstracts of the 90th Annual Meeting of the Paläontologische Gesellschaft (PDF). SNSB - BSPG, München. p. 141. ISBN   978-3-946705-07-9. Archived (PDF) from the original on 2023-05-17.
  31. ↑ The Complete Guide to Prehistoric Life (1 ed.). Firefly Books. 2006. ISBN   1-55407-181-X.
  32. ↑ Hua, Stéphane; Liston, Jeff; Tabouelle, Jérôme (March 2024). "The Diet of Metriorhynchus (Thalattosuchia, Metriorhynchidae): Additional Discoveries and Paleoecological Implications". Fossil Studies. 2 (1): 66–76. doi: 10.3390/fossils2010002 . ISSN   2813-6284.
  33. ↑ "BBC - Science & Nature - Sea Monsters - Fact File: Metriorhynchus". www.bbc.co.uk. Retrieved 2024-08-05.
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