Reassessment of Uquiasaurus heptanodonta, an Iguanian Lizard from the Late Pliocene (Uquía Formation) of Northwestern Argentina

Abstract

Uquiasaurus heptanodonta was originally described as an iguanian lizard from the Uquía Formation (Late Pliocene) of NW Argentina, known from numerous skull elements. Reexamination of preserved bones indicates the type series comprises more than one species belonging to the extant iguanian genus Liolaemus. The presence of a premaxilla with seven tooth positions among the bone assemblage suggests that species belonging to Liolaemus nigromaculatus group or Liolaemus montanus section have been present in this region up to the Late Pliocene (3.0 to 2.5 Ma), thus expanding the fossil record of the genus Liolaemus in the NW Argentina.