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==Description== |
==Description== |
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''Mesodermochelys'' had elongated front flippers.<ref name="Hirayama, 2007"/> One fossil found in Japan's [[Kagawa Prefecture]] had a [[carapace]] estimated to be 1.3 metres in length.<ref name="Hirayama et al., 2006"/> Only the neural or spinal [[scute]]s, or individual plates, of the carapace are well-grooved.<ref name="Hirayama & Chitoku, 1996"/> |
Like other dermocheyliids, ''Mesodermochelys'' had elongated front flippers.<ref name="Hirayama, 2007"/> One fossil found in Japan's [[Kagawa Prefecture]] had a [[carapace]] estimated to be 1.3 metres in length.<ref name="Hirayama et al., 2006"/> Only the neural or spinal [[scute]]s, or individual plates, of the carapace are well-grooved.<ref name="Hirayama & Chitoku, 1996"/> |
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==Specimens== |
==Specimens== |
Revision as of 22:24, 27 July 2008
Mesodermochelys Temporal range: Late Cretaceous
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Genus: | Mesodermochelys Hirayama & Chitoku, 1996 [1]
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Mesodermochelys is an extinct genus of sea turtle that existed during the Late Cretaceous, from the Santonian to the Campanian of what today is Japan.[2] The genus was discovered and named by Ren Hirayama and Tsutomu Chitoku in 1996,[3] and contains one species, the type species M. undulatus.[1] Studies of the skull of M. undulatus indicate that it was a primitive cheloniid that was closely-related to the Protostegidae.[2] It has been described as the best representative of Mesozoic dermochelyiids.[1]
Description
Like other dermocheyliids, Mesodermochelys had elongated front flippers.[2] One fossil found in Japan's Kagawa Prefecture had a carapace estimated to be 1.3 metres in length.[3] Only the neural or spinal scutes, or individual plates, of the carapace are well-grooved.[1]
Specimens
In October 2005, Yoshiyuki Hattori uncovered a skull of Mesodermochelys, in the Santonian-age Yezo Group in the Hokkaido Prefecture.[2] Though weathering had caused the absence of most of the dermal roofing elements on the skull, it is regarded as being the best-preserved specimen of a Mesodermochelys skull.[2] The skull was donated to the Hokkaido Museum, where a study using formic acid to etch the fossil from its matrix revealed certain characteristics about the skull.[2] Other, less complete specimens of Mesodermochelys skulls and jaws have been found in the Maastrichtian type locality of the Hokkaido Prefecture.[2] A total of fifteen specimens have been uncovered, including an almost-complete shell.[1]
References
- ^ a b c d e f 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.
- ^ a b c d e f g Hirayama R. 2007. Cranial morphology of Mesodermochelys (Chelonioidea; Testudines) from the Late Cretaceous of Japan. Journal of Vertebrate Paleontology 27 (3): 89A.
- ^ a b 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.