EOCENE LAND MAMMALS FROM SEYMOUR ISLAND, ANTARCTICA - PALEOBIOGEOGRAPHICAL IMPLICATIONS

Middle Eocene land mammals from La Meseta Formation, Seymour (Marambio ) Island are reviewed. A taxonomically diverse fossil land-vertebrate assemblage with small and medium-size mammals has been recovered from four localities. The depositional setting is shallow marine and most o f the mammal-bearing beds are in reworked, moderate to high energy sub tidal facies. The characteristics of these mammals not only confirm bu t also strengthen the biogeographical relationships between southern S outh America (Patagonian Province) and the Antarctic Peninsula during the Paleogene and rule out the possibility of a major barrier between these areas. The Antarctic ungulates (Astrapotheria and ?Litopterna) a re plesiomorphics in retaining low crowned cheek teeth and are more si milar to those from the Pancasamayoran local faunas of southern South America (Patagonia).