Sinemydidae is an extinct family of
turtle
Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...
s from the Jurassic and Cretaceous of East Asia.
Their exact position is engimatic, they have alternatively been considered stem-group
cryptodires, but also "crownward stem-turtles" alongside
Macrobaenidae,
Paracryptodira
__NOTOC__
Paracryptodira is an extinct group of reptiles in the clade Testudinata (which contains modern turtles and their extinct relatives), known from the Jurassic to Paleogene of North America and Europe. Initially treated as a suborder siste ...
,
Xinjiangchelyidae
Xinjiangchelyidae is an extinct family of turtles known from the Lower Jurassic to the Middle Cretaceous of Asia and western Europe. They have generally been interpreted as either being basal Cryptodira, cryptodires or placed outside of crown Tes ...
,
Thalassochelydia and
Sandownidae outside of crown Testudines.
Genera
*''
Dracochelys''
, China, Early Cretaceous (Aptian-Albian)
*''
Hongkongochelys''
Upper
Shaximiao Formation
The Shaximiao Formation () is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the ...
, China, Middle-Late Jurassic
*''
Jeholochelys''
Jiufotang Formation
The Jiufotang Formation () is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see Jehol Biota). It is a member of the Jehol group. T ...
, China, Early Cretaceous (Aptian)
*''
Liaochelys''
Jiufotang Formation, China, Early Cretaceous (Aptian)
*''
Manchurochelys''
Yixian Formation
The Yixian Formation (; formerly Romanization of Chinese, transcribed as Yihsien Formation or Yixiang Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. I ...
, China, Early Cretaceous (Aptian)
*''
Ordosemys''
**''O''. ''leios''
Luohandong Formation, China, Early Cretaceous
**''O''. ''liaoxiensis''
Chengzihe Formation, China, Early Cretaceous (Aptian)
**''O''. ''brinkmania'' Lianmugin Formation, China, Early Cretaceous (Aptian-Albian)
**''O''. ''perforata''
Khulsangol Formation, Mongolia, Early Cretaceous (Albian)
**''O''. ''donghai''
Chengzihe Formation, China, Early Cretaceous (Aptian-Albian)
*''
Sinemys''
**†''Sinemys brevispinus'' Tong and Brinkman 2012
Laohongdong Formation, China, Early Cretaceous
**†''Sinemys chabuensis'' Ji and Chen 2018
Jingchuan Formation, China, Early Cretaceous (
Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...
)
**†''Sinemys gamera'' Brinkman and Peng 1993
Luohandong Formation, China, Early Cretaceous (
Valanginian
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac ...
-
Hauterivian
The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...
)
**†''Sinemys lens'' Wiman 1930
Mengyin Formation, China, Early Cretaceous (
Berriasian
In the geological timescale, the Berriasian is an age/ stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 143.1 ±0.6 Ma and 137.05 ± 0.2 (million years ago) ...
-Valanginian)
*''
Wuguia''
**†''Wuguia efremovi'' Khozatsky 1996
Hutubei Formation, China, Hauterivian/Barremian Lianmuxin Formation, China, Early Cretaceous (Aptian-Albian)
**†''Wuguia hutubeiensis'' Matzke et al. 2004 Hutubei Formation, China, Hauterivian/Barremian
*''
Xiaochelys''
Lianmugin Formation, China, Early Cretaceous (Aptian-Albian)
*''
Yumenemys''
Hui-Hui-P'u, China, Late Cretaceous
Material from the Paleocene of California previously attributed to c.f. Sinemyididae is now attributed to macrobaenids.
References
External links
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{{paleo-turtle-stub