A Complex Association of Invertebrates, Vertebrates and Trace Fossils in the Marine Camacho Formation (Late Miocene of Uruguay): Biostratigraphy and Paleoenvironments

Abstract

A complex fossil association from the San Pedro Member of the Camacho Formation (late Miocene) in Puerto Arazatí, San José department, southern Uruguay, is documented in this paper. Situated at the base of the coastal cliffs, this association is characterized by many land mammals, trace fossils indicative of the Psilonichnus Ichnofacies, and irregularly distributed oyster bioherms. The trace fossils are interpreted as crab galleries, which represent a clear marginal, or even intertidal to supratidal episode within the overall marine environment recognized for the Camacho Formation. Episodic subaerial exposure of the deposits under consideration is inferred by the presence of the Psilonichnus Ichnofacies and a set of trace fossils assigned to sarcosaprophagous insects, found in the skeleton of some specimens of glyptodonts. Finally, a review of the mastofauna and the mollusks from the main localities of the San Pedro Member was conducted. This study permits redefining the biostratigraphy of this unit and confirms its late Miocene age.