Sistemática y antigüedad de Paramyocastor diligens (Ameghino, 1888) (Rodentia, Caviomorpha, Myocastoridae)

VERZI, D.H.; DESCHAMPS, C.M.; VUCETICH, M.G.

AMEGHINIANA

Año: 2002 vol. 39 p. 193 - 200

0002-7014

Materials (including the holotypes) of the nominal species of the myocastorids Myopotamus (=Myocastor) diligens Ameghino, Paramyocastor intactus Ameghino, Isomyopotamus affinis Rovereto, and Isomyopotamus albañiri Reig, are analyzed. We propose that differences in molar morphology among these species represent individual and, especially, ontogenetic variability. Consequently, these taxa are considered synonymous, being Paramyocastor diligens (Ameghino) the correct combination. A new specimen found in the lower levels of the Monte Hermoso Formation confirms the record of P. diligens in sediments of Montehermosan Age. Therefore, the biochron of this myocastorid is Montehermosan-Upper Chapadmalalan (Late Miocene- Late Pliocene).