Foraminíferos uniloculares, Eoceno inferior, Isla Grande de Tierra del Fuego y la plataforma continental adyacente, Argentina

Abstract

"A diverse group of unilocular calcareous Foraminifera comprising at least twenty five species is described from the Lower Eocene of the Río Bueno and Punta Torcida Formations, Austral Basin, Tierra del Fuego Island, Argentina, The group is characterized by the abundance of Conotagena acuticosta (Reuss) and the earliest records of the genus Cushmanina. It includes at least five species already known in the Danian fram Patagonia; nearly 20% of the species are extant. This group comprises approximately one third of the benthie foraminiferal species reeognized in the Lower Eocene, this proportion indicates a conspicuous increase in the number of unilocular species in relation to the thirteen recorded from the Danian of Patagonia. The unilocular assemblage of the the Río Bueno Fm. is dominated by C. acuticosta (ca. 50%) whereas the assemblage of the Punta Torcida Pm, is dominated by Fissurina sp. 2 (ca. 28%). Oolina ona n. sp. and Conolagena costatoreticulata n. sp, both sculptured in reticular patterns, and Cusumanina primitiva n. sp. and C. oliveroi n, sp, are described. "