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Thoracosaurus

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Thoracosaurus
Temporal range: Late Cretaceous - Early Paleocene, 70.6–61.6 Ma[1]
Thoracosaurus macrorhynchus skull and jaws from the Paleocene (Danian) of Sweden
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Superfamily: Gavialoidea
Genus: Thoracosaurus
Leidy, 1852
Species
  • Thoracosaurus neocesariensis (de Kay, 1842 [originally Gavialis neocesariensis]) (type)
  • Thoracosaurus isorhynchus (Pomel, 1847)
  • Thoracosaurus macrorhynchus (de Blainville, 1855)

Thoracosaurus is an extinct genus of long-snouted eusuchian which existed during the Late Cretaceous and Early Paleocene in North America and Europe.

Taxonomy

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Thoracosaurus had traditionally been thought to be related to the modern false gharial, largely because the nasal bones contact the premaxillae. Phylogenetic work starting in the 1990s instead supported affinities within Gavialoidea exclusive of such forms,[2] although a 2018 tip dating study simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data suggests that it might have been a non-crocodylian eusuchian.[3]

The genus contains the type species Thoracosaurus neocesariensis in North America,[4] and what is either Thoracosaurus isorhynchus or Thoracosaurus macrorhynchus from Europe; a recent review[5] argues that T. macrorhynchus is a junior synonym of T. isorhynchus, but it is unclear whether the type of T. isorhynchus allows differentiation of European and North American Thoracosaurus; if not, then T. isorhynchus would be a nomen dubium. A number of species have been referred to this genus, but most are dubious.[2]

Ecology

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It is thought to have inhabited marine environments.[6]

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References

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  1. ^ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9: e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
  2. ^ a b Brochu, C. A. (2006). "Osteology and phylogenetic significance of Eosuchus minor (Marsh, 1870) new combination, a longirostrine crocodylian from the Late Paleocene of North America". Journal of Paleontology. 80 (1): 162–186. doi:10.1666/0022-3360(2006)080[0162:OAPSOE]2.0.CO;2.
  3. ^ Michael S. Y. Lee; Adam M. Yates (2018). "Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil record". Proceedings of the Royal Society B: Biological Sciences. 285 (1881): 20181071. doi:10.1098/rspb.2018.1071. PMC 6030529. PMID 30051855.
  4. ^ Page 125; A study of fossil vertebrate types in the Academy of Natural Sciences of Philadelphia: taxonomic, systematic, and historical perspectives Issue 16 of Special Publication Series, Academy of Natural Sciences (Philadelphia, Pa.) By Earle E. Spamer, Edward Daeschler, L. Gay Vostreys-Shapiro. Academy of Natural Sciences, 1995 ISBN 0-910006-51-2 ISBN 978-0-910006-51-4
  5. ^ Brignon, A. (2017). "The collecting of fossil vertebrates in Mont-Aimé (Marne, France) by the Baron de Ponsort (1792–1854)". Bulletin d'Information des Géologues du Bassin de Paris. 54 (3): 20–44.
  6. ^ Puértolas-Pascual, Eduardo; Blanco, Alejandro; Brochu, Christopher A.; Canudo, José Ignacio (January 2016). "Review of the Late Cretaceous-early Paleogene crocodylomorphs of Europe: Extinction patterns across the K-PG boundary". Cretaceous Research. 57: 565–590. doi:10.1016/j.cretres.2015.08.002.