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Thalassomedon

Thalassomedon
Temporal range: Late Cretaceous, 99.6–93.5 Ma
Mounted cast of the type specimen, American Museum of Natural History
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Sauropterygia
Order: Plesiosauria
Family: Elasmosauridae
Genus: Thalassomedon
Welles, 1943
Species:
T. haningtoni
Binomial name
Thalassomedon haningtoni
Welles, 1943
Synonyms
  • Alzadasaurus riggsi Welles, 1943

Thalassomedon (from Greek, thalassa, "sea" and Greek, medon, "lord" or "ruler", meaning "sea lord") is a genus of plesiosaur, named by Welles in 1943.

Description

Restoration
Detail of Thalassomedon skull at the American Museum of Natural History

Thalassomedon is among the largest elasmosaurids, with the holotype measuring 10.86 metres (35.6 ft) long and weighing more than 4.44 metric tons (4.89 short tons).[1][2] There is a larger skull, however, suggesting a much larger animal, potentially up to 11.6 metres (38 ft).[3] The neck is also very long; it comprises 62 vertebrae[4] and is about 5.9 metres (19 ft) - over half of the total length. The skull is 47 centimetres (19 in; 1.54 ft) long, with 5 centimetres (2.0 in) long teeth. The flippers were about 1.5–2 metres (4.9–6.6 ft) long. Stones have been found in its stomach area leading some to theorize that they were used for ballast or digestion. If the latter, stomach action would cause the stones to help grind ingested food.

Discovery

Neck vertebrae

This genus of plesiosaur lived in North America, approximately 95 million years ago - this places it during the Cenomanian stage. Its closest relative is Elasmosaurus, and both belong to the family Elasmosauridae. There are six specimens of varying states of preservation on display at various museums in the United States.

See also

References

  1. ^ O'Gorman, J.P. (2016). "A Small Body Sized Non-Aristonectine Elasmosaurid (Sauropterygia, Plesiosauria) from the Late Cretaceous of Patagonia with Comments on the Relationships of the Patagonian and Antarctic Elasmosaurids". Ameghiniana. 53 (3): 245–268. doi:10.5710/AMGH.29.11.2015.2928. hdl:11336/54311. S2CID 133139689.
  2. ^ O'Gorman, J.P.; Santillana, S.; Otero, R.; Reguero, M. (2019-10-01). "A giant elasmosaurid (Sauropterygia; Plesiosauria) from Antarctica: New information on elasmosaurid body size diversity and aristonectine evolutionary scenarios". Cretaceous Research. 102: 37–58. Bibcode:2019CrRes.102...37O. doi:10.1016/j.cretres.2019.05.004. ISSN 0195-6671. S2CID 181725020.
  3. ^ Smith, Elliott Armour. (2020). "Revision of the Genus Styxosaurus and Relationships of the Late Cretaceous Elasmosaurids (Sauropterygia: Plesiosauria) of the Western Interior Seaway". Theses, Dissertations and Capstones. 1335. https://mds.marshall.edu/etd/1335
  4. ^ Carpenter, K. (1999). "Revision of North American elasmosaurs from the Cretaceous western interior." Paludicola, 2(2): 148-173.