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

Abstract

<p>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.: <i>Patene simpsoni</i>; Polydolopimorphia, Bonapartheriiformes, Argyrolagoidea: family, genus, and species indet.; and Bonapartherioidea, Prepidolopidae: <i>Punadolops alonsoi</i> and <i>Coloradolops cardonensis</i> gen. et sp. nov. <i>Patene simpsoni</i> is also found in the Tonco Valley, near Los Cardones, and at São José de Itaboraí, Rio de Janeiro, Brazil. <i>Punadolops alonsoi</i> 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. <i>Coloradolops cardonensis</i> 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.</p> <p><a href="http://zoobank.org/urn:lsid:zoobank.org:pub:7B4333A4-CB78-4F52-B479-571748A46488" target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:7B4333A4-CB78-4F52-B479-571748A46488</a></p