Morphology of dentition and posteranial skeleton of Akidolestes

Akidolestes cifellii Li and Luo, 2006 (NIGPAS 139281A, B) is a new symmetrodont mammal with complete postcranial skeleton discovered in Yixian Fromation, Lower Creatacous, Liaoning province, China. It has been diagnosed as a member of family spalacotheriidae included in superfamily spalacotheroidea. The spalacotheriidae is a monophyletic group; characteristic by the reversed triangular molar. It is the close relative to extant therians (metatherians and eutherians), with a lot of primitive features. Akidolestes differs from zhangheotheriids in having much broader coronoid process of dentary and more acute angled molars. The skeletal anatomical and morphological comparative study indicates that the evolution of Akidolestes is mosaic pattern combing the primitive and the derived skeletal features. Akidolestes probably shares both terrestrial and arboreal locomotory adaptation, but it is not specialized in either aspects.