Soft-shelled turtles (Trionychidae) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan: Skull-based taxa and probable skull-shell associations

In this paper we describe previously unpublished trionychid turtle material, consisting of skull fragments, from the Late Cretaceous (late Turonian) Bissekty Formation of the Dzharakuduk locality in Uzbekistan. This material is assigned to two taxa: the skull-based Khunnuchelys kizylkumensis Brinkman et al. (1993, Can. J. Earth Sci. 30, 2214-2223) and Trionychini indet. Two specimens which cannot be confidently attributed to these two taxa are considered Trionychidae indet. In addition to these trionychid taxa known from skulls, the Dzharakuduk turtle assemblage includes at least two shell-based taxa, Aspideretoides cf. A. riabinini and “Trionyx” cf. “T.” kansaiensis. For this and other Late Cretaceous localities of Middle Asia and Kazakhstan, we suggest the probable skull-shell associations of Khunnuchelys spp. with “Trionyx” kansaiensis-like forms and Trionychini indet. with Aspideretoides-like forms.     

A new trionychid turtle from the Early Cretaceous of Heilongjiang Province,Northeastern China

A new soft-shelled turtle (“Trionyx” jixiensis sp. nov.) from the Lower Cretaceous Chengzihe Formation, Jixi city, Heilongjiang Province, China is described on the basis of a nearly complete carapace. The new species is diagnosed by the absence of suprascapular fontanelles and absence of a preneural; eight neurals, tetragonal fifth neural; and eight pairs of costals, with the large eighth costals meeting after the eighth neural. Due to the incompleteness of the specimen and confused classification of the genera of trionychids, the new species cannot be included in any genus of Trionychinae and is temporarily assigned to “Trionyx” (sensu lato). “Trionyx” jixiensis is one of the earliest trionychids, its discovery indicates that the family was already diversified during the Early Cretaceous in Asia.