The fossil Scincomorpha (Lepidosauria) of South America

BRIZUELA, S.; ALBINO, A. M.

Rio de Janeiro, Brasil

Simposio; Evolution of Lepidosaurs in Gondwana (II Congreso Latinoamericano de Paleontología de Vertebrados); 2005

The South American lizard fossil record is poorly known in contrast to that of the northern hemisphere. Supposed lizards remains from the Jurassic of Patagonia and the presence of a teiid in the Early Cretaceous of Chile could not be corroborated. Although Tijubina pontei from the Cretaceous of northeastern Brazil was previously cited as a teiid lizard, it has recently been defined as the sister-group of the crown-group Squamata (Scleroglossa + Iguania). Pristiguana brasiliensis from the Santonian-Maastrichtian of Brazil is the best known lizard from the South-American Mesozoic. It was alternatively assigned to the Iguania and to the Teiidae family. Late Cretaceous outcrops of Patagonia provided a lizard dentary remain of Early Campanian age that resembles that of Pristiguana. All these remains suggest that Patagonia may have been an unsuspected territory for Mesozoic lizard evolution as it was for other reptiles. With regard to the Cenozoic, representatives of the two extant Teiidae subfamilies, and a possible Scincidae, have been mentioned for the Middle Paleocene of Brazil. Later, an extinct Early Eocene teiid from the northwest of Argentina is currently under revision. Another extinct teiid species, reported from the Middle Miocene of Colombia (Paradracaena colombiana), has affinities with the extant Dracaena. However, the first record of an extant teiid genus (Tupinambis) comes from the Early Miocene of Patagonia. The Cenozoic record of the Scincomorpha is dominated by the genus Tupinambis. The living Callopistes, represented by the extinct species C. bicuspidatus, from the Pliocene of the Pampean Region, is the only other Tupinambinae genus so far reported. Teiinae genera appear in the Pleistocene, with records of Ameiva and Dicrodon in Brazil and Ecuador, respectably. Cnemidophorus is present in the Late Quaternary of Argentina, in an area where it does not occur at present. Finally, presences of Tupinambis and scincids have been documented for some archaeological sites of Argentina.