REGISTRO DE PRESBIORNÍTIDOS (AVES, ANSERIFORMES) EN SEDIMENTITAS DE LA FORMACIÓN VACA MAHUIDA, LA PAMPA, ARGENTINA

The discovery of a presbyornithid (Aves, Anseriformes) from the Vaca Mahuida Formation is reported. The formation crops out at Sierra El Fresco, southeast of Puelen (La Pampa, Argentina). This occurrence indicates that the deposition of the formation dates from the late Paleocene-middle Eocene; the presence of shallow, brackish-water environments is inferred. KEY WORDS. Argentina. La Pampa Province. Paleogene. Aves. Presbyornithidae. Palaeoenvironments.