Ordosemys liaoxiensis (Ji, 1995)

Taxonomy

Turtle

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia Laurenti 1768
Order: Testudines Batsch 1788
Family: Sinemydidae Yeh 1963
Genus: Ordosemys
Species: Ordosemys liaoxiensis
Author Citation Ji, 1995

Geological Time Scale

Eon: Phanerozoic
Era: Mesozoic
Period: Cretaceous
Sub Period: None
Epoch: Early
International Age: Barremian - Early Aptian

Stratigraphy

Yixian Formation
Jianshangou Member

Provenance

Acquired by: Purchase/Trade

Location

Beipiao
Chaoyang
Liaoning
China

• china
• liaoning
• linyuan
• ordosemys
• tff-oilshale-ch591

Comments

Synonym: Manchurochelys liaoxiensis.

Taxonomy from Fossilworks.org.

Modified diagnosis for the genus from Brinkman and Peng, 1993a by Tong et al. 2004, p. 2: "A cryptodire with a low domed shell and plastron loosely connected to the carapace as in macrobaenids, differing from all other macrobaenids in having a shell that is nearly as wide as long, in the presence of a preneural and in the presence of a medial fontanelle between the hypoplastron and xiphiplastron; differering from Macrobaena Tatarinov, 1959, Anatolemys Khozatskii and Nesov, 1979, Hangaiemys Sukhanov and Narmandakh, 1974, and Kirgizemys Nesov and Khozatskii, 1973 in that the vertebral scutes are wider than they are long; differering from Sinemys Wiman, 1930 and Manchurochelys Endo and Shikama, 1942 in having the posterior lobe of the plastron wider at the basis. Skull similar to Macrobaena and differing from Hangaiemys and Dracochelys Gaffney and Ye, 1992 in having a wider triturating surface; canalis caroticus internus unfloored or with a thin floor, the foramina anterior canalis caroticus interni located close together at the base of the sella turcica, with sella turcica reduced in size, not reaching the dorsum sellae.

Diagnosis for the species from Tong et al., p. 3 (modified from Ji, 1995, Li and Liu, 1999): "A species of Ordosemys, differing from O. leios in having a slight ornamentation on the shell surface, a large semicircular lateral fontanelle on the bridge, and in having the first peripheral not contacting or barely contacting the first costal plate."

Line drawing of the shell (dorsal view) from Tong et al. 2004, p. 13:

Identified by oilshale.

References:
Tong, H.; Ji, S. U. A.; Ji, Q. (2004) Ordosemys (Testudines: Cryptodira) from the Yixian Formation of Liaoning Province, Northeastern China: new specimens and systematic revision. American Museum Novitates 438: 1.

Zhou, C.-F. and Rabi, M. (20159 A sinemydid turtle from the Jehol Biota provides insights into the basal divergence of crown turtles. Scientific Reports 5:16299:1-12.