PRESENCIA DE MACROEUPHRACTUS RETUSUS (XENARTHRA, DASYPODIDAE) EN EL PLIOCENO DEL AREA MESOPOTAMIA (ARGENTINA). SU IMPORTANCIA BIOESTRATIGRAFICA y PALEOBIOGEOGRAFICA

Abstract

The Pliocene genus Macroeuphractus (Xenarthra, Dasypodidae ) is known by three species: Macroeuphractus morenoi from the "Araucanense" of the Province of Catamarca, and Epecuén Formation of the Province of La Pampa; MaclOeuphractus retusus from the "Herrnosense" and Mácroeuphractus outesi from the "Chapadrnalense", both latter from the Buenos Aires southern litoral region. The registration of Macroeuphractus retusus in the "Mesopotamiense" confirms a Pliocene age, in part representing the Later Pliocene as other evidences indica te it. The southern pampean region, from the first beginning, had two different biogeographical connections with the Sub tropical Dominio: by the W through the subandine valleys and by the E through what nowadays are the chaquean and mesopotamian plaine.