Abstract
A new fossil teiid lizard from the Upper Cretaceous Marshalltown Formation (Campanian) of Monmouth County, New Jersey is described as Prototeius stageri, gen. et sp. nov. Based on the holotypic dentary and referred specimens, the genus is diagnosed by a strongly differentiated heterodont dentition, five premaxillary teeth, paired frontals with well developed crista cranii, and a broad, low sagittal crest on the parietal. Prototeius appears most closely related to Chamops segnis and Leptochamops denticulatus from the Late Cretaceous of western North America. In a preliminary phylogenetic revision of the Teiidae, Chamops is removed from the Tupinambinae, and Leptochamops and Meniscognathus are removed from the Teiinae. These genera are placed together into a new subfamily, Chamopsiinae, defined as Chamops, Prototeius, Leptochamops, Meniscognathus, their most recent common ancestor and its descendants. The revised phylogeny does not support the placement of Chamops within the Tupinambinae or Leptochamops and Meniscognathus within the Teiinae. Therefore the origin or presence of the two extant teiid subfamilies cannot be traced to the Late Cretaceous of North America based on known fossil genera.