Additional data on early Paleocene metatherians (Mammalia) from Punta Peligro

A.M. FORASIEPI; G.W. ROUGIER

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH

Blackwell Verlag GmbH

Lugar: Oxford; Año: 2009 vol. 47 p. 391 - 398

0947-5745

Metatherian remains from Punta Peligro (Chubut Province, Argentina; Salamanca Formation, early Paleocene) are scarce, but at present, there are at least four different taxa known by dental remains. We describe here an incomplete petrosal showing metatherian affinities. Among the dentally known taxa from the same stratigraphic levels, the overall size of the petrosal fits that predicted for Derorhynchus, which in turn was assigned to the order Didelphimorphia. The features of the petrosal we describe do not correspond with the morphology observed among didelphoid marsupials, the only members of Didelphimorphia with well known basicrania, suggesting that if the association of petrosal and dental remains is correct, then referral of Derorhynchus to the Didelphimorphia has to be revised. The taxonomic content of this group of marsupials, as presently interpreted, represents a paraphyletic or polyphyletic grouping of metatherians.