New records of Lagostomus Brookes (Rodentia, Chinchillidae) in the late Miocene of Argentina and its biostratigraphic importance

Abstract

In this work, we present two new records of Lagostomus from the late Miocene of Argentina. A right mandible from the Huachipampa Formation (Loma del Camello, San Juan Province) is assigned to Lagostomus telenkechanum, previously recorded in the Arroyo Chasicó Formation (Chasicoan Stage/Age, late Miocene; Arroyo Chasicó, Buenos Aires Province). A skull fragment from the Cerro Azul Formation (Salinas Grandes de Hidalgo, La Pampa Province) is referred to L. pretrichodactyla, previously recorded in several units assigned to the Huayquerian Stage/Age (late Miocene) in Catamarca and Mendoza provinces, and sediments of uncertain age in Buenos Aires Province. The presence of L. telenkechanum in the Huachipampa Formation supports a Chasicoan age for this unit, which corroborates previous hypotheses, and extends the area of distribution of this species. The presence of L. pretrichodactyla in the Cerro Azul Formation suggests a late Miocene age (probably Messinian) for this unit, at least at Salinas Grandes de Hidalgo, supporting previous hypothesis. These new records allow recognizing the biostratigraphic value of Lagostomus to a higher geographic scale than previously considered.