INVESTIGADORES
FORASIEPI Analia Marta
congresos y reuniones científicas
Título:
NEW MIDDLE PALEOCENE MARSUPIALS FROM CENTRAL PATAGONIA
Autor/es:
GOIN, F. J.; CANDELA A.; FORASIEPI, A. M.
Lugar:
Chicago, Illinois
Reunión:
Jornada; 57 Annual Meeting, Society of Vertebrate Paleontology; 1997
Institución organizadora:
Society of Vertebrate Paleontology
Resumen:
An unusually rich association of fossil marsupials recorded from middle Paleocene (Itaboraian Age) levels of the Las Flores Formation, in central Patagonia (Argentina) confirms previous hypotheses of the early, rapid metatherian radiation in South America by the beginning of the Age of Mammals. No less than 36 new species representative of all major taxa known in South America (Peradectia, Didelphimorphia, Sparassodonta, Polydolopimorpha, Paucituberculata, and Microbiotheria) give new insights into the early ameridelphian radiation. Most adaptative types can be recognized among the new taxa: carnivores, insectivores, and frugivores. The latter two are particularly abundant. Half of the approximately 700 marsupial molars recovered by screen-washing at this site are referable to epidolopine and polydolopine polydolopimorphians, ranging from minute to fox-sized. The Las Flores marsupial association has no less than a dozen genera in common with the fauna of Sao Jose do Itaboraí (Brazil), the type locality of the Itaboraian Land-Mammal Age, confirming their contemporaneity. However, some striking differences in faunal composition apparently reflect latitudinal differences. For instance, there are no less than four new species of polydolopine polydolopimorphians in the Las Flores Formation, while polydolopines are unknown from fossil localities outside of Patagonia. The Las Flores taxa are also larger and more derived than those from the type locality. The Las Flores marsupial fauna supports the concept of great antiquity (latest Cretaceous or earliest Paleocene) for the marsupial radiations in South America, and that by at least the middle Paleocene, biogeographic differences had already stabilized between low latitude (e.g., the Iaboraí) faunas and more southerly (Weddelian) faunas.