New Palaeogene metatherians from the Quebrada de Los Colorados Formation at Los Cardones National Park (Salta Province, Argentina)

Abstract

The Quebrada de Los Colorados Formation (Los Cardones National Park, Salta Province, north-western Argentina), is an Eocene–Oligocene unit well represented in the Calchaquí Valley area. Here we describe a new metatherian association recorded from the base of this formation, inferred as middle Eocene. Represented taxa are: Sparassodonta, family indet.: Patene simpsoni; Polydolopimorphia, Bonapartheriiformes, Argyrolagoidea: family, genus, and species indet.; and Bonapartherioidea, Prepidolopidae: Punadolops alonsoi and Coloradolops cardonensis gen. et sp. nov. Patene simpsoni is also found in the Tonco Valley, near Los Cardones, and at São José de Itaboraí, Rio de Janeiro, Brazil. Punadolops alonsoi was originally described from the Geste Formation in Salta and Catamarca provinces. Hitherto, no other Argyrolagoidea have been found in north-western Argentina in the Palaeogene. Coloradolops cardonensis is unique to the locality and levels here described. The preservation of part of the skull constitutes the best prepidolopid remains known. North-western Argentina is a key region for the study of the evolution of South American mammals, since it has a singular geographical location between the Neotropics and the southernmost part of South America. Due to biogeographical constraints, it may lead to a better comprehension of the continental distribution of metatherian lineages during Cenozoic times.

http://zoobank.org/urn:lsid:zoobank.org:pub:7B4333A4-CB78-4F52-B479-571748A46488

Keywords:

• Metatheria
• Sparassodonta
• Polydolopimorphia
• Eocene
• Calchaquí Valley
• NW Argentina

Acknowledgements

We want to thank Roberto Canelo, Rosaura Garro, and Nicolás Maiolli, rangers in the Los Cardones National Park, who facilitated our work and helped in many ways; Julio Monguillot, María Elena Sánchez, and Juliana De Gracia from the Delegación Regional NOA (Administración de Parques Nacionales); and Luis Alvarado and Leonardo Montoya from the IBIGEO. Mariano Zubiri helped us in the field and was our personal nanny. We wish also to thank Graciela Parma, José Luis Garrido, and Pablo Tubaro from the National Application Authority of Law 25,743. We wish to thank Fabián Tricárico, who took the SEM images, and Marcela Tomeo, who helped us with the figures. Finally, Judith Babot sent us images of Patene simpsoni from Tucumán Province in the Vertebrate Palaeontology collection at the Instituto Miguel Lillo. This work was supported by PICT 2014-2497 to N. Zimicz; PICT 201-0508 to N. Zimicz, L. Chornogubsky, and J. C. Fernicola; PUE 22920160100098 to L. Chornogubsky and J. C. Fernicola; and PICT 2015-2245 and IBIGEO-PUE to P. Payrola.

Supplemental data

Supplementary material for this article can be accessed at: https://doi.org/10.1080/14772019.2017.1417333