Naomichelys is an extinct genus of helochelydrid stem turtle known from the Cretaceous (Aptian-Campanian) of North America. It is the only member of the family known to be native to North America.
| Naomichelys Temporal range: Early Cretaceous
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| Fossil carapace of N. speciosa, Field Museum of Natural History | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Pantestudines |
| Clade: | Testudinata |
| Family: | †Helochelydridae |
| Genus: | †Naomichelys Hay, 1908 |
| Type species | |
| Naomichelys speciosa Hay, 1908
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Distribution
editNaomichelys is known numerous remains from western North America, most notably the holotype partial shell from the Cloverly Formation of Montana and a complete skeleton from the Antlers Formation of Texas. Indetermiate remains are known extending up to the Campanian in the United States and Canada.[1] It is the only known North American member of Helochelydridae.[2][3]
Location
editAfter[1]
- Kootenai Formation, Montana, Early Cretaceous (Aptian)
- Arundel Formation, Maryland, Aptian
- Cloverly Formation, Montana and Wyoming, Aptian
- Trinity Group, Texas, Aptian-Albian
- Willow Tank Formation, Nevada, Albian
- Cedar Mountain Formation, Utah, Albian-Cenomanian
- Kaskapau Formation, British Columbia, Turonian
- Straight Cliffs Formation, Utah, Turonian-Santonian
- Tropic Shale, Utah, Turonian-Santonian
- Mooreville Chalk, Alabama, Santonian-Campanian
- Milk River Formation, Alberta, Santonian-Campanian
- Foremost Formation, Campanian
- Two Medicine Formation, Montana, Campanian
- Mesaverde Formation, Wyoming, Campanian
- Wahweap Formation, Utah, Campanian
- Menefee Formation, New Mexico Campanian
Taxonomy
editNaomichelys is a member of the family Helochelydridae, which is known from Late Jurassic to Late Cretaceous deposits in North America and Europe.
References
edit- ^ a b Gentry, Andrew D.; Ebersole, Jun A. (2021-08-10). "The first occurrence of the stem turtle Naomichelys from the Late Cretaceous of eastern North America". Historical Biology. 34 (7): 1129–1136. doi:10.1080/08912963.2021.1962855. ISSN 0891-2963. S2CID 238677455.
- ^ Hay, O.P. 1908. The Fossil Turtles of North America. Carnegie Institute of Washington, Washington DC. https://doi.org/10.5962/bhl.title.1250
- ^ W. G. Joyce, J. Sterli, and S. D. Chapman. 2014. The skeletal morphology of the solemydid turtle Naomichelys speciosa from the Early Cretaceous of Texas. Journal of Paleontology 88(6):1257-1287