Sigmodontinos (Mammalia, Rodentia) Pleistocenicos del sudoeste de la provincia de Buenos Aires (Argentina): aspectos sistematicos, paleozoogeograficos y paleoambientales

Abstract

Several sigmodontine remains from Ensenadan sediments (Early-Middle Pleistocene) of Bajo San Jose (southwestern Buenos Aires province) are described. The oldest records of Lundomys (Tribe Oryzomyini), Oxymycterus (Tribe Akodontini) and Phyllotis (Tride Phyllotini) were recovered, together with Akodon cf. A. iniscatus, Akodon cf. A. azarae, Akodon sp., Reithrodon auritus, and Calomys cf. C. laucha-C musculinus. Paleoenvironmental and paleozoogeographic data provided by these sigmodontines, together with those of the remaining vertebrate fauna, prove a mixture of Brazilian and Patagonian species. The generic-specific composition characteristic of the modern cricetid associations of the Pampean Region was settled during the Ensenadan Age.