Ren Hirayama

Waseda University | Sōdai

Kappachelys okurai gen. et sp. nov. is named and described based on two isolated carapacial elements (right seventh costal and left seventh peripheral) from the Lower Cretaceous (?upper Neocomian) Akaiwa Formation of west-central Honshu, Japan. Kappachelys is a small turtle (shell length *10 cm) that exhibits a unique combination of three features:...

The bone-bearing beds of the Lower Cretaceous Kuwajima Formation (Tetori Group) are described. Three facies of bone-bearing beds (Facies I: carbonaceous sandstones; Facies II: dark grey fine-grained silty sandstones; Facies III: dark greenish-grey mudstones) are present in inter-channel deposits that originated on a floodplain. The grain size of th...

Osteopygis emarginatus Cope 1868 is described from the Lower Tertiary of the Ouled Abdoun phosphate basin, Morocco, on the basis of skulls and lower jaws. Osteopygis is a cosmopolitan turtle that had a wide geographical distribution during the Late Cretaceous and Paleocene. Osteopygis emarginatus is a very conservative species which crossed the Cre...

Phylogenetic relationships of the genus Cuora sensu lato (Cuora sensu stricto and Cistoclemmys) and other testudinoid genera were inferred from variations in 882 base positions of mitochondrial 12S and 16S rRNA genes. Results yielded a robust support to the monophyly of a group (Cuora group) consisting of Cuora sensu lato and the monotypic Pyxidea....

Anomalochelys angulata, a new genus and species is described as the most abberant taxon of the Nanhsi-ungchelyidae (order Testudines, superfamily Trionychoidea), an extinct land turtle group of the Creta-ceous, on the basis of a good carapace and partial plastron collected from the Upper Cretaceous of Hobe-tsu-cho, Central Hokkaido, North Japan. An...

During the Cretaceous, non-marine turtles show strong patterns of provincialism, mirroring the pattern of land masses resulting from the breakup of Pangea since the Jurassic. These patterns are a result of several factors, of which vicariancy and ecological controls on the distribution of groups of turtles are considered the most significant. The l...

Chelonioid sea turtles (Order Testudinata; Superfamily Chelonioidea) first appear in the early Cretaceous (Aptian-Albian). Their long fossil record is excellent compared to most marine tetrapods. Nonetheless, there has been no inclusive attempt to provide an analysis of cladistic relationships among this group. In this paper, a chelonioid classific...

Fossil turtles collected from the Sinda Beds of eastern Zaire contain three families. They are Erymnochelys sp. of family Pelomedusidae, gen. et sp. Indet. of family Carettochelyidae, and gen. et sp. indet of family Trionychidae. Among them is the first known occurrence from Africa of carettochelyid, the pig-nosed turtle, Erymnochelys, the bigheade...