Sinemydidae

Sinemydidae is an extinct family of turtles from Cretaceous to Paleocene deposits in Asia and North America. Their exact position is engimatic, they have alternatively been considered stem-group cryptodires, but also "crownward stem-turtles" alongside Macrobaenidae, Paracryptodira, Xinjiangchelyidae, Thalassochelydia and Sandownidae outside of crown Testudines.

Genera

 * Dracochelys Lianmugin Formation, China, Early Cretaceous (Aptian-Albian)
 * Hongkongochelys Upper Shaximiao Formation, China, Middle-Late Jurassic
 * Jeholochelys Jiufotang Formation, China, Early Cretaceous (Aptian)
 * Liaochelys  Jiufotang Formation, China, Early Cretaceous (Aptian)
 * Manchurochelys Yixian Formation, 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)
 * †Sinemys gamera Brinkman and Peng 1993 Luohandong Formation, China, Early Cretaceous (Valanginian-Hauterivian)
 * †Sinemys lens Wiman 1930 Mengyin Formation, China, Early Cretaceous (Berriasian-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