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Mesodermochelys

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This is an old revision of this page, as edited by Bennbreeden (talk | contribs) at 04:26, 19 April 2021 (Specimens: Added information about holotype specimen and earliest referred specimens. Elaborated on history of Hokkaido Museum and eliminated uninformative vague information.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Revision as of 04:26, 19 April 2021 by Bennbreeden (talk | contribs) (Specimens: Added information about holotype specimen and earliest referred specimens. Elaborated on history of Hokkaido Museum and eliminated uninformative vague information.)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff) Extinct genus of turtles

Mesodermochelys
Temporal range: Late Cretaceous Campanian–Maastrichtian PreꞒ O S D C P T J K Pg N
Mesodermochelys undulatus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Chelonioidea
Family: Dermochelyidae
Genus: Mesodermochelys
Hirayama & Chitoku, 1996
Type species
Mesodermochelys undulatus
Hirayama & Chitoku, 1996

Mesodermochelys is an extinct genus of sea turtle known from the Campanian to the Maastrichtian (Late Cretaceous) of what today is Japan. One species is known, the type species M. undulatus; it was given its binomial name by Ren Hirayama and Tsutomu Chitoku in 1996. Studies of its skull indicate that it was a primitive member of the Dermochelyidae (leatherback turtle family) that was closely related to the Protostegidae. It has been described as the best representative of Mesozoic dermochelyids.

Description

Restoration of two Mesodermochelys (middle) and other sea creatures swimming around a Kamuysaurus carcass

Like other dermochelyids, Mesodermochelys had elongated front flippers. One fossil found in Japan's Kagawa Prefecture had a carapace estimated to be 1.3 metres in length. Only the neural or spinal scutes, or individual plates, of the carapace are well grooved.

Specimens

The holotype specimen of Mesodermochelys undulatus Hobetsu Museum (HMG) 5 was collected in 1980. It comprises a supraoccipital and partial postcranial skeleton and was reported in 1996 along with 14 referred specimens collected between 1977 and 1994 and also reposited at HMG.

In October 2005, Yoshiyuki Hattori uncovered a skull of Mesodermochelys, in the Santonian-age Yezo Group in the Hokkaido Prefecture. The skull is very well preserved but is missing most of the dermal roof bones through weathering. It was donated to the defunct Historical Museum of Hokkaido, which has since been integrated into and replaced by the Hokkaido Museum. A total of fifteen specimens have been uncovered, including an almost-complete shell.

References

  1. ^ Hirayama R, Chitoku T. (1996). "Family Dermochelyidae (Superfamily Chelonioidea) from the Upper Cretaceous of North Japan". Transactions and proceedings of the Palaeontological Society of Japan. New series 184: 597-622. online, retrieved 28 July 2008
  2. ^ Hirayama R. (2007). "Cranial morphology of Mesodermochelys (Chelonioidea; Testudines) from the Late Cretaceous of Japan". Journal of Vertebrate Paleontology 27 (3): 89A. online, retrieved 28 July 2008
  3. ^ Hirayama R, Fujii A, Takahashi K. (2006). "A dermochelyid sea turtle from the Upper Cretaceous (Late Campanian) Izumi Group of Shionoe, Takamatsu, Kagawa Prefecture, Western Japan". Fossils (Palaeontological Society of Japan) 80: 17-20. online, retrieved 28 July 2008
Dermochelyidae family
Genera
Species of the Dermochelyidae family
Leatherback sea turtle
Arabemys
Corsochelys
Cosmochelys
DermochelysLeatherback sea turtle
Eosphargis
Mesodermochelys
Psephophorus
Phylogenetic arrangement of turtles based on turtles of the world 2017 update: Annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status. †=Extinct.
Testudines
Suborder
Superfamily
Family
Genus
Cryptodira
Chelonioidea
(Sea turtles)
Cheloniidae
Dermochelyidae
 
Kinosternoidea
Dermatemydidae
Kinosternidae
Testudinoidea
Emydidae
Geoemydidae
 Platysternidae
Testudinidae
Trionychia
Carettochelyidae
Trionychidae
 
 
Chelydridae
Nanhsiungchelyidae
Protostegidae
 
Pleurodira
 
Araripemydidae
Bothremydidae
Chelidae
Pelomedusidae
Podocnemididae
Sahonachelyidae
 
 
 
Taxon identifiers
Mesodermochelys
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