Sinemydidae is an extinct family of turtles from Cretaceous to Paleocene deposits in Asia and North America.^[1][2] 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.

Sinemydidae Temporal range: Oxfordian–Paleocene PreꞒ Ꞓ O S D C P T J K Pg N
Jeholochelys
Manchurochelys
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Pantestudines
Clade:	Testudinata
Clade:	Perichelydia
Family:	†SinemydidaeYeh, 1963 Genera See text Genera edit Dracochelys[3] Lianmugin Formation, China, Early Cretaceous (Aptian-Albian) Hongkongochelys[3] Upper Shaximiao Formation, China, Middle-Late Jurassic Jeholochelys[3] Jiufotang Formation, China, Early Cretaceous (Aptian) Liaochelys[1][3] Jiufotang Formation, China, Early Cretaceous (Aptian) Manchurochelys[3] Yixian Formation, China, Early Cretaceous (Aptian) Ordosemys[3] 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[3] †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[3] †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[1][3] Lianmugin Formation, China, Early Cretaceous (Aptian-Albian) Yumenemys[3] Hui-Hui-P'u, China, Late Cretaceous References edit ^ a b c C.-F. Zhou; M. Rabi (2015). "A sinemydid turtle from the Jehol Biota provides insights into the basal divergence of crown turtles". Scientific Reports. 5: 16299. Bibcode:2015NatSR...516299Z. doi:10.1038/srep16299. PMC 4639786. PMID 26553740. ^ "Sinemydidae". Fossilworks. Retrieved 17 December 2021. ^ a b c d e f g h i j "Sinemydidae". Fossilworks. Retrieved 17 December 2021. External links edit "Chelonii: Centrocryptodira". palaeos.com. Archived from the original on April 5, 2023.