Una Fauna Local Lujanense (Pleistoceno Superior–Holoceno Inferior) del sur de Uruguay: Santa Regina, Departamento de Colonia

Abstract

A Lujanian Local Fauna (Upper Pleistocene–Lower Holocene) from southern Uruguay: Santa Regina, Colonia Department. On the southwestern coast of Uruguay, in the Colonia and San José departments, sedimentary rocks that correspond to the Neogene and Quaternary are found. Herein we describe the fossiliferous locality of Santa Regina, located on the east coast of the department of Colonia. The stratigraphic profile shows at the base grayish-green sandy rocks belonging to the Camacho Formation (Upper Miocene). Overlying this unit, there is a tough yellowish-greenish siltstone in net contact, in which several pieces of a Notiomastodon platensis specimen were found. Towards the upper part, a thicker greenish-brownish bed is observed, ranging upwards from conglomerates to siltstones. The lower part of this bed includes disarticulated and fragmentary remains of Lestodonarmatus, Glyptodon reticulatus, Pampatheriidae indet., Toxodon cf. T. platensis, Morenelaphus sp., and Lycalopex gymnocercus, and to the top large portions of carapaces of Glyptodon sp. and Panochthus sp. The aforementioned mastofaunistic assemblage corresponds to the Lujanian Mammal Age or regional Stage (Upper Pleistocene-Greenlandian). The lithostratigraphy allows us to refer the two upper levels to the Dolores Formation, a characteristic unit of the Quaternary of southern Uruguay, and not to the Raigón Formation, as indicated in some previous reports for this locality. The presence of Lestodon armatus, Glyptodon reticulatus, Notiomastodon platensis, Lycalopexgymnocercus, and the probable presence of Toxodon platensis, allow us to infer landscapes of open or semi-open areas, with a predominance of grasslands and shrubs during the genesis of the deposits. Keywords: LatePleistocene–Early Holocene, land mammals, stratigraphy, Uruguay.