Systematic description of three new mammals (Notoungulata and Rodentia) from the Early Miocene Cerro Bandera Formation, Northern Patagonia, Argentina

KRAMARZ, A.; BOND, M.; ARNAL, M.

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2015 vol. 52 p. 585 - 597

0002-7014

The Cerro Bandera Formation is amostly pyroclastic continental unit exposed in isolated areas of east-centralNeuquén Province, northwestern Patagonia. Several mammals from these depositswere previously reported and support a Colhuehuapian age (early Miocene) forthese levels. New findings reveal that this unit bears a much more diverseassemblage and calls into question this age assessment. Here we describe threenew species. Protypotherium sinclairi sp. nov. (Notoungulata,Interatheriidae) is similar in size to the Santacrucian Protypotheriumaustrale Ameghino, butdiffers from all the species of the genus by having less reduced p3?p4 talonids. Doryperimysolsacheri gen. et sp. nov.(Rodentia, Neoepiblemidae) has hypselodont, prismatic cheek teeth that combinefeatures of species of Perimys Ameghino and Scotamys antiquus Loomis. Thesystematic position of Leucokephalos maior sp. nov. within Caviomorpha is stilluncertain, but it is definitively allied to the Deseadan Leucokephaloszeffiae Vucetich, Dozo,Arnal, and Pérez in sharing rooted cheek teeth with an almost identical earlyocclusal simplification that resembles the 8-shaped configuration of some earlyoctodontoids and putative chinchilloids. The three species co-occur at a singlefossil locality and stratigraphic level on the northeastern slope of BardaNegra; P.sinclairi and D.olsacheri are also recordedin other levels exposed in different isolated outcrops of the Cerro BanderaFormation. Doryperimysolsacheri ?like otherpreviously described rodents from this unit? is unknown in other presumablycoeval mammal associations, but the biochronological and paleobiogeographicmeaning of this assemblage is still under study.