A new lizard (Reptilia: Squamata) with exquisite preservation of soft tissue from the Lower Cretaceous of Inner Mongolia, China

摘要

The Early Cretaceous Jehol Biota of China includes seven named lizard taxa: Yabeinosaurus tenuis and Dalinghosaurus longidigitus; the gliding Xianglong; more fragmentary remains referred to the genera Pachygenys and Mimobecklesisaurus; and the undiagnostic juvenile skeletons Jeholosaurus and Liaoningolacerta. Here we describe new lizard remains from the Yixian Formation at Liutiaogou, Ningcheng County, Inner Mongolia. The eight specimens vary in size and ontogenetic development, but appear to pertain to a single species. Several specimens show unparalleled preservation of soft tissue impressions including scalation and pigmentation, claw sheaths, sternal and extrastapedial cartilages, as well as rarely preserved skeletal elements like orbitosphenoids and postcloacal bones. The combination of characters precludes attribution to known taxa both within and outside China, and the new lizard is named Liushusaurus acanthocaudata gen. et sp. nov. Cladistic analysis supports the placement of Liushusaurus within the Scincogekkonomorpha, as the sister group of Scleroglossa.