A NEW BEAKED WHALE (ODONTOCETI, ZIPHIIDAE) FROM THE MIDDLE MIOCENE OF PERU.

The article describes Nazcacetus urbina, a beaked whale (Odontoceti, Ziphiidae) from the middle Miocene levels of the Pisco Formation at Cerro los Quesos in Peru. The species was described based on partial odontocete skeleton. It is characterized with a strong reduction of the upper and lower dentitions, a Tasmacetus-like vertex, short mandibular symphysis and an abrupt elevation of the dorsal margin of the mandible. Phylogenetic analysis showed that Nazcacetus is a crown ziphiid. The morphological traits observed in Nazcacetus, such as reduction of teeth, small temporal fossa and large hamular process, note that such taxon possessed the suction feeding capacities of Recent ziphiids.