Teiid-like Scincomorphan Lizards from The Late Cretaceous (Campanian) of Southern Utah

Abstract

Teiid-like scincomorphan lizards from the Late Cretaceous (Campanian) of the Kaiparowits Formation of southern Utah include Chamops cf. Chamops segnis, cf. Leptochamops, a new species of Meniscognathus, and a new taxon with well-developed tricuspid teeth. These taxa comprise some of the only confirmed reports of these types of lizards from Late Cretaceous rocks south of Wyoming, allowing for a more comprehensive investigation of the distributional and evolutionary patterns of teiid-like scincomorphans from the Campanian. The majority of the known taxa are from the Western Interior west of the margin of the midcontinental sea that bisected North America during the Late Cretaceous. The teiid-like scincomorphans from the Campanian comprised two distinct faunas; one in the north (e.g., Montana, Western Canada) and one in the south (e.g., Utah, New Mexico). These two faunas share Chamops and potentially Leptochamops, but each region also has two to four endemic taxa representing a diversity that correlates to latitudinal differences. Teiid-like scincomorphans present in North America prior to the establishment of the midcontinental seaway are not nearly as diverse as during the Campanian, indicating that the radiation of forms followed the establishment of the seaway, although it may not have played a direct role.