Fossil mammals of the Quebrada de los Colorados Formation (late middle Eocene) at the locality of La Poma, Salta Province, Argentina

Abstract

An anatomical and taxonomic analysis of the mammalian record in the locality of La Poma in Salta Province, Argentina, is here presented. This record consists in two specimens exhumed in levels of the Quebrada de los Colorados Formation referred to the middle late Eocene. The first specimen is represented by a partial skull preserving mostly the rostrum and some dental pieces and was identified as a member of Leontiniidae, although it does not bear enough information for generic or specific determination. The second specimen is represented by more complete material, preserving much of the dentition. It was identified as a new species of the genus Pampahippus, traditionally included in the paraphyletic family Notohippidae. The leontiniid here studied presents several plesiomorphic features identified in other taxa of northwestern Argentina, and this material represents a new example of a pre-Deseadan basal morphotype within the family. Regarding the new species of Pampahippus, it shows clear signs of rising hypsodonty, representing the first case for a notoungulate lineage in the Paleogene of northwestern Argentina.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:45D87764-5B63-4487-BAAC-74F8D490AE18

Keywords:

• Quebrada de los Colorados Formation
• Northwestern Argentina
• Leontiniidae
• Pampahippus
• Middle late Eocene

Acknowledgements

We thank Agustin Scanferla (IBIGEO-P) and Pablo Ortiz (PVL) for allowing us to study material under their care. We are also indebted to Darin Croft and an anonimous reviewer who made valuable suggestions and useful comments that greatly improved the manuscript.