A new Teiidae species (Squamata, Scincomorpha) from the Late Pleistocene of Rio Grande do Sul State, Brazil

The fossil record of the Teiidae in South America is restricted almost exclusively to the Cenozoic, with the group mainly represented by Tupinambis during Miocene-Holocene times. Currently, this genus includes the largest lizards of the New World as well as the largest members of the family. Tupinambis uruguaianensis nov. sp., the first fossil squamate from Rio Grande do Sul State, is represented by a right lower jaw, basicranium, three dorsal vertebrae, and a left radius and ulna of the same individual. The material comes from the Touro Passo Formation, where reptiles were previously represented only by Testudines. The new species shares several characters with the living species of Tupinambis, but is distinguished from all them by an articular bone with a deeply concave ventral margin, angular process is more rounded, proportionally larger and projecting beyond the ventral and posterior adjacent limits, and a very protuberant adductor crest so that the lateral articular bone surface is lateroventrally directed.