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Suchosaurus

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Suchosaurus
Temporal range:Early Cretaceous(ValanginiantoAptian),139.8–122.46Ma
Holotypetooth ofS. cultridensseen from two angles
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Spinosauridae
Subfamily: †Baryonychinae
Genus: †Suchosaurus
Owen,1841
Type species
†Suchosaurus cultridens
Owen,1841
Species
  • †S. cultridensOwen, 1841 (type)
  • †S. girardiSauvage,1897
Synonyms

Suchosaurus(meaning "crocodile lizard" ) is aspinosauriddinosaurfromCretaceousEngland and Portugal, originally believed to be agenusofcrocodile.Thetype material,consisting of teeth, was used by BritishpalaeontologistRichard Owento name thespeciesS. cultridensin1841.Later in 1897, French palaeontologistHenri-Émile Sauvagenamed a second species,S. girardi,based on two fragments from themandibleand one tooth discovered in Portugal.Suchosaurusis possibly asenior synonymof the contemporary spinosauridBaryonyx,but is usually considered adubious namedue to the paucity of its remains, and is considered an indeterminatebaryonychine.In theWadhurst Clay Formationof what is now southern England,Suchosauruslived alongside other dinosaurs, as well asplesiosaurs,mammals,andcrocodyliforms.

History of discovery

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In about 1820, BritishpalaeontologistGideon Mantellacquired teeth discovered nearCuckfieldin theWadhurst ClayofEast Sussex,part of a lot with the present inventory numberBMNHR36536. In 1822, he reported these, after an identification byWilliam Clift,as belonging to crocodiles.[1]In 1824, the teeth were mentioned and illustrated byGeorges Cuvier,representing the firstfossilillustration of aspinosauriddinosaur(though this group wouldn't be recognized for nearly another century).[2]In 1827 Mantell described additional teeth, pointing out the similarities to thecrocodiliansTeleosaurusandGavialis.[3]One of these teeth is the present specimen BMNH R4415, others are part of BMNH R36536.[citation needed]

Typemandibleand tooth ofS. girardi

In1841,British palaeontologistRichard Owennamed, based on BMNH R36536 as asyntypeseries, asubgenusCrocodylus(Suchosaurus)with astype speciesCrocodylus (Suchosaurus) cultridens.[4]The subgeneric name was derived from Greek σοῦχος,souchos,the name of the Egyptian crocodile godSobek.This reflected the presumed taxonomic affinities; at the time the crocodile-like snouts of spinosaurids were not known. Thespecific nameis derived fromLatinculter,"dagger", anddens,"tooth", in reference to the elongated form of the teeth. In 1842, Owen again mentioned thetaxonas a subgenus,[5]subsequently he and other workers would use it as a fullgenusSuchosaurus.In 1842 and 1878 Owen referred somevertebrae(backbones) toSuchosaurus,[6]but these were later identified byRichard Lydekkeras likely belonging toornithischiandinosaurs instead.[7]In 1884, Owen indicated a tooth as "Suchosaurus leavidens"in a caption,[8]this is usually seen as alapsus calami(or "slip of the pen" ) because this species is not further mentioned.[citation needed]

In 1897, French palaeontologistHenri-Émile Sauvagenamed a second species:Suchosaurus girardi,based on two jaw fragments (specimen MG324) and a tooth, found in thePapo Seco Formationof Portugal by Swiss-PortuguesegeologistPaul Choffat.Thespecific namehonours French geologist Albert Girard.[9]The tooth was considered lost but was rediscovered and in 2013 reported as specimen MNHN/UL.I.F2.176.1, part of remains recovered after a fire in 1978.[10]

During the nineteenth and most of the twentieth century,Suchosauruswas usually considered to have been some obscure crocodilian, perhaps belonging to thePholidosauridae.[11]Single comparable teeth discovered in England were referred to the genus.[7]However, when publishing a redescription ofBaryonyxin 1998, British palaeontologistAngela Milnerrealised that the teeth of that spinosaurid dinosaur were extremely similar to those ofSuchosaurus.In 2003, she suggested both genera represented one and the same animal.[12]An identity would imply the nameSuchosaurushas priority. However, theSuchosaurusteeth are also indistinguishable from those ofCristatusaurusandSuchomimus,making it an indeterminatebaryonychine.[citation needed]

Skeletal reconstruction of the relatedBaryonyx

In 2007, French palaeontologistEric Buffetautconsidered the teeth ofS. girardivery similar to those ofBaryonyx(andS. cultridens) except for the stronger development of the ribs (lengthwise ridges) on thetooth crown,suggesting that the remains belonged to the same genus. Buffetaut agreed with Milner that the teeth ofS. cultridenswere almost identical to those ofB. walkeri,but with a ribbier surface. The former taxon might be asenior synonymof the latter (since it was published first), depending on whether the differences were within a taxon or between different ones. According to Buffetaut, since the holotype specimen ofS. cultridensis one worn tooth and that ofB. walkeriis a skeleton it would be more practical to retain the newer name.[13]In 2011, Portuguese palaeontologistOctávio Mateusand colleagues agreed thatSuchosauruswas closely related toBaryonyx,but considered both species in the former genus (Suchosaurus)nomina dubia(dubious names) since their holotype specimens were not considered diagnostic (lacking distinguishing features) and could not be definitely equated with other taxa.[14]

Description

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Holotype tooth ofS. cultridensin 2011

In 2012,Americanvertebrate palaeontologistThomas R. Holtz Jr.tentatively estimatedSuchosaurusat around 10 metres (33 ft) in length and weighing between 1 and 4 tonnes (1.1 and 4.4 short tons).[15][16]And in 2016, Spanish palaeontologists Molina-Pérez and Larramendi estimatedS. cultridensat approximately 8.6 m (28 ft) long, 2.15 m (7.1 ft) tall at the hips and weighing 1.4 t (1.5 short tons).[17]The teeth ofSuchosaurus girardiwere curved, oval in cross section, and had tallrootsthat were one and a half times taller than the crown. Its teeth, like some other spinosaurids, bore flutes (lengthwise grooves), inS. girardi,there were eight flutes on thelingualside (which faced the inside of the mouth), and four less distinct flutes on thelabialside (which faced the outside of the mouth). Thetooth enamel,or outermost layer, had a microscopic wrinkled texture.[14]

Palaeoecology

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Hypotheticallife restoration

The Wadhurst Clay Formation, part of theWealden Group,is dated to theValanginianstageof theEarly CretaceousPeriod,about 139.8 to 132.9 million years ago.[18]It consists mainly ofshalesandmudstones.[19]Other dinosaurs that shared this environment withSuchosaurusincluded theiguanodontiansBariliumandHypselospinus,[20]as well as the dubious speciesMegalosaurus dunkeriand an unnamedmaniraptoran.[21][22]They coexisted with theplesiosaurHastanectes,[23]thecrocodyliformGoniopholis[24]and the mammalsLoxaulax,[25]Aegialodon,[26]Laolestes,[27]andSpalacotherium.[28]

References

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  1. ^Mantell, G.A., 1822,The fossils of the South Downs or Illustrations of the Geology of Sussex,London, Rupton Relfe
  2. ^Cuvier, G., 1824,Recherches sur les ossemens fossiles, deuxième édition.Dufour & d’Ocagne, Paris. 547 pp
  3. ^Mantell, G.A., 1827,Illustrations of the geology of Sussex,London, Lupton Relfe. 92 pp
  4. ^Owen, R. (1840–1845).Odontography.London: Hippolyte Baillière, 655 pp, 1–32
  5. ^Owen, R., 1842,Report on British fossil reptiles. Part II.Reports of the meetings of the British Association for the Advancement of Science. 11, pp 61-204
  6. ^Owen, R., 1878,Monograph on the fossil Reptilia of the Wealden and Purbeck Formations. Supplement VIII, (Goniopholis, Petrosuchus, and Suchosaurus).Palaeontolographical Society Monographs, 32, pp 1-15
  7. ^abLydekker, R., 1888,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.British Museum of Natural History, London. 309 pp
  8. ^*Owen, R., 1884,A History of British Fossil Reptiles, Volume II.Cassell, London. 224 pp
  9. ^Sauvage, H. E. (1897–1898).Vertébrés fossiles du Portugal. Contribution à l’étude des poissons et des reptiles du Jurassique et du Crétacique.Lisbonne: Direction des Travaux géologiques du Portugal, 46p
  10. ^Malafaia, E.; Ortega, F.; Escaso, F.; Mocho, P., 2013, "Rediscovery of a lost portion of the holotype ofSuchosaurus girardi(Sauvage, 1897-98), now related to the spinosaurid theropodBaryonyx",In: Torcida Fernández-Baldor, F.; Huerta, P. (Eds.).Abstract book of the VI International Symposium about Dinosaurs Palaeontology and their Environmentpp 82-84
  11. ^Buffetaut, E., 2010, "Spinosaurs before Stromer: Early finds of spinosaurid dinosaurs and their interpretations",Geological Society, London, Special Publications. 343,pp 175-188
  12. ^Milner, A., 2003, "Fish-eating theropods: A short review of the systematics, biology and palaeobiogeography of spinosaurs". In: Huerta Hurtado and Torcida Fernandez-Baldor (eds.).Actas de las II Jornadas Internacionales sobre Paleontologýa de Dinosaurios y su Entorno (2001).pp 129-138
  13. ^Buffetaut, E. (2007). "The spinosaurid dinosaurBaryonyx(Saurischia, Theropoda) in the Early Cretaceous of Portugal. "Geological Magazine,144(6): 1021-1025.doi:10.1017/S0016756807003883
  14. ^abMateus, O.; Araújo, R.; Natário, C.; Castanhinha, R. (2011)."A new specimen of the theropod dinosaurBaryonyxfrom the early Cretaceous of Portugal and taxonomic validity ofSuchosaurus"(PDF).Zootaxa.2827.2827:54–68.doi:10.11646/zootaxa.2827.1.3.
  15. ^Holtz, Thomas R. Jr. (2011)Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,Winter 2010 Appendix.
  16. ^Holtz, T. R. Jr. (2014)."Supplementary Information toDinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages".University of Maryland.Retrieved2014-09-05.
  17. ^Molina-Peréz & Larramendi (2016).Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos.Barcelona, Spain: Larousse. p. 275.ISBN9780565094973.
  18. ^Hopson, P.M., Wilkinson, I.P. and Woods, M.A. (2010)A stratigraphical framework for the Lower Cretaceous of England.Research Report RR/08/03. British Geological Survey, Keyworth.
  19. ^Lake, R.D. & Shepard-Thorn, E.R. (1987)Geology of the country around Hastings and Dungeness: Memoir for 1:50,000 geological sheets 320 and 321.British Geological Survey, London.
  20. ^Holtz, T. R.; Molnar, R. E.; Currie, P. J. (2004). "Basal Tetanurae". In Weishampel, D. B.; Dodson, P.; Osmolska, H. (eds.).The Dinosauria(2 ed.). Berkeley: University of California Press. p. 559.ISBN978-0-520-24209-8.
  21. ^Naish, D. and Sweetman, S.C. (2011). "A tiny maniraptoran dinosaur in the Lower Cretaceous Hastings Group: evidence from a new vertebrate-bearing locality in south-east England."Cretaceous Research,32:464-471.doi:10.1016/j.cretres.2011.03.001
  22. ^Michael W. Maisch (2016). "The nomenclatural status of the carnivorous dinosaur genusAltispinaxv. Huene, 1923 (Saurischia, Theropoda) from the Lower Cretaceous of England ".Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen.280(2): 215–219.doi:10.1127/njgpa/2016/0576.
  23. ^Benson, R. B. J.; Ketchum, H. F.; Naish, D.; Turner, L. E. (2012). "A new leptocleidid (Sauropterygia, Plesiosauria) from the Vectis Formation (Early Barremian–early Aptian; Early Cretaceous) of the Isle of Wight and the evolution of Leptocleididae, a controversial clade".Journal of Systematic Palaeontology.11(2): 233–250.doi:10.1080/14772019.2011.634444.S2CID18562271.
  24. ^De Andrade, M. B.; Edmonds, R.; Benton, M. J.; Schouten, R. (2011)."A new Berriasian species ofGoniopholis(Mesoeucrocodylia, Neosuchia) from England, and a review of the genus ".Zoological Journal of the Linnean Society.163:S66–S108.doi:10.1111/j.1096-3642.2011.00709.x.
  25. ^Simpson, G. G. (1928). "A catalogue of the Mesozoic mammalia in the geological department of the British Museum".London: British Museum (Nat Hist).
  26. ^Kermack, K. A.; Lees, Patricia M.; Mussett, Frances (1965). "Aegialodon dawsoni, A New Trituberculosectorial Tooth from the Lower Wealden".Proceedings of the Royal Society of London. Series B, Biological Sciences.162(989): 535–554.Bibcode:1965RSPSB.162..535K.doi:10.1098/rspb.1965.0055.ISSN0080-4649.JSTOR75561.PMID4378463.S2CID39141524.
  27. ^Foster, J. (2007). "Appendix."Jurassic West: The Dinosaurs of the Morrison Formation and Their World.Indiana University Press. pp. 327-329.
  28. ^"Spalacotherium Owen 1854 - Encyclopedia of Life".eol.org.Retrieved2020-04-21.
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