Resumen
Three dental pieces of a notoungulate mammal, found in the strata of the upper part of the Chucal Formation, Altiplano of Arica, northern Chile (18-19°S) are described. The morphological characters allow to refer the available material to a Toxodontidae, related to generalised specimens of Haplodontheriinae as Palyeidodon (= Prototrigodon), which are present in Argentina. These specimens, morphologically more advanced than those of Santacrucian Mammal Age (Lower Miocene), give sufficient evidence to assign to Colloncuran (Early Middle Miocene) the maximum age of the deposits where they are present.