New Metatherian Mammal from the Early Eocene of Antarctica

GOIN, FRANCISCO J.; VIEYTES, EMMA C.; GELFO, JAVIER N.; CHORNOGUBSKY, LAURA; ZIMICZ, ANA N.; REGUERO, MARCELO A.

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Lugar: Berlin; Año: 2018

1064-7554

A new Paleogene metatherian from locality IAA 1/90, Marambio (Seymour) Island in the Antarctic Peninsula is described.Pujatodon ektopos, gen. et sp. nov., is recognized on the basis of a tiny lower left molar recovered from early Eocene (lateYpresian) levels of the Cucullaea I Allomember, La Meseta Formation. The tooth is characterized by its small size, bunoid aspect,short trigonid with closely set paraconid and metaconid, wide and long talonid, the development of an incipient cingulid at thelabial base of the crown between the trigonid and talonid, and an expanded posterior cingulid. Body mass estimations for the newtaxon range from 83.13 to 153.15 g. Its enamel microstructure shows the earliest evidence among metatherians of aligned prisms,as well as of interprismatic sheets of matrix. The analysis of other parameters, like body mass, molar morphometric index, andwear facets, suggests that the molars of Pujatodon were primarily adapted to the processing of fruits, nuts, seeds, and/or hardinsects. Several features suggest the allocation of this specimen among basal polydolopimorphians (Prepidolopidae or, moreprobably, Glasbiidae). The discovery of the specimen MLP 14-I-10-20 could offer new insights on the origins and earlydiversification of Australidelphian marsupials in southern (and northern?) continents. It also adds significant information onthe diversity of Antarctic Paleogene mammals, their evolution, habits, and historical biogeography.