A Late Cretaceous lizard assemblage from the Allen Formation, northern Patagonia, Argentina

ABSTRACT

Lizards are poorly known from the Mesozoic of South America, including several specimens from the Lower and Upper Cretaceous of Brazil, and only a few from the Upper Cretaceous of Patagonia. Here, we describe a new lizard assemblage from a single bone-bearing level in the Allen Formation (upper Campanian – lower Maastrichtian), cropping out at the Cerro Tortuga locality, Río Negro Province, northern Patagonia, Argentina. We recognise the presence of three different taxa, all of them represented by partially isolated maxillae, belonging to different lizard lineages: pleurodontan Iguania; Teiioidea; and possibly Scincoidea. These specimens support the presence of a quite diverse lizard assemblage during the Late Cretaceous in southern South America, suggesting that their absence in other Cretaceous deposits from Patagonia represents preservational and/or sampling bias. The taxonomic diversity also points to a broad ecological diversity, because the three taxa strongly differ in their dental morphology and inferred dietary habits. The assemblage from Cerro Tortuga indicates that lizards, along with snakes and sphenodontians, were an important component of the Late Cretaceous lepidosaurian fauna of South America and, likely, Gondwana.

KEYWORDS:

• Squamata
• lizards
• Patagonia
• Allen Formation
• Late Cretaceous

Acknowledgments

We would like to thank Daniel Cabaza and Liliana Lopez (Museo Municipal de Lamarque) for access to specimens, support, and assistance both in the field and the collections. We also thank Sergio Bogan (Fundación de Historia Natural Félix de Azara, Universidad Maimónides) for providing access to specimens under his care. Additional thanks to the large number of volunteers, students and colleagues that have done much of the collecting and picking, in particular Leandro A. Canessa whose help has made much of this work possible. Thanks are extended to two anonymous reviewers for their comments that greatly improved the quality of the manuscript. We also thank Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEN-UBA) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) of Argentina for continuous support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Partial funding for this project was provided by the Department of Anatomical Sciences and Neurobiology, University of Louisville and [PICT 2016 2682] and [PIP778] from the Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación, Argentina (GWR). Additionally, GWR benefitted from Fulbright Scholarship [FSP-P006734] for use in the study of comparative material and manuscript preparation.