A new polyglyphanodontian lizard from the Upper Cretaceous of southern China implies a complex evolutionary history of the clade

Polyglyphanodontian lizards were one of the dominant groups among squamates during the Late Cretaceous. They were widely distributed and exhibited a great range of body sizes and high morphological variation. The Asian taxa are preserved mostly as complete or nearly complete skulls or skeletons, therefore providing substantial anatomical information for the clade. Here, we describe a new polyglyphanodontian genus and species from the Upper Cretaceous of Ganzhou Basin, Jiangxi Province, China. The new taxon is diagnosed by its unique dentition, with complex posterior teeth having mesial, distal and lingual expansions, connected by crests and with depressions between. The phylogenetic analyses support an assignment of the new taxon to Polyglyphanodontia, forming an unresolved clade with Polyglyphanodon, Gilmoreteius, Adamisaurus, Tianyusaurus and Yechilacerta, or being a sister taxon to either Adamisaurus or a small clade of Tianyusaurus and Yechilacerta. The cranial and dental morphology suggests the new lizard was omnivorous, contrasting with the specialized herbivory of Tianyusaurus and Yechilacerta from the same region. Moreover, the new lizard is the first polyglyphanodontian taxon from Asia with a complex dentition, which shows similarities with that of some North American taxa, and this may suggest the evolutionary history of Polyglyphanodontia is more complicated than previously thought.