EOCENE MAMMALS AND CONTINENTAL STRATA FROM PATAGONIA AND ANTARCTIC PENINSULA

GELFO, J.N.; REGUERO, M.A.; LÓPEZ, G.M.; CARLINI, A.A.; CIANCIO, M.R.; CHORNOGUBSKY, L.; BOND, M.; GOIN, F. J.; TEJEDOR, M.F.

Bulletin of the Museum of Northern Arizona

Naughton and Gunn, Inc.

Lugar: Flagstaff, Arizona; Año: 2009 vol. 65

The mammalian faunal succession in South America is well documented throughout the Eocene from about 47 to 37 Ma. Most Eocene land mammal-bearing deposits occur in Patagonia and in basins of the Antarctic Peninsula, and these have been studied intensely over the last 20 years. The geology of the San Jorge (eastern Patagonia), “Volcanic-Pyroclastic Complex” (western Patagonia), and James Ross (Antarctic Peninsula) basins are here reviewed and their faunal content analyzed. The geochronology of Itaboraian and Riochican South American Land Mammals Ages (SALMAs), usually regarded as late Paleocene, is also discussed. In order to evaluate the similarity between Eocene faunas, a cluster analysis applying the Simpson coefficient was performed using a data matrix with 13 faunas and 228 taxa. The faunas represent both classic and new localities from Antarctica, Patagonia, Mendoza, and central Chile, and we analyzed three taxonomic categories (genus, family, and order) so that faunas lacking common genera could be compared. The analysis supports at least three major clusters. The first, which consists of faunas from western Patagonia (the Paso del Sapo localities) plus Antarctica, seems to fall biochronologically between the Riochican and Casamayoran SALMAs. The second cluster is divided between faunas related to the Casamayoran and those related to the younger Mustersan SALMA. The latest Eocene-earliest Oligocene faunas also group together and are represented by three Tinguirirican faunas plus a fourth younger fauna which seems to be pre-Deseadan (Oligocene).