ProthylacinusProthylacinus is an extinct genus of South American metatherian, that lived during the Early Miocene.DescriptionProthylacinus had a vestigial hallux that was most likely not visible in life. The humerus bore the epicondylar foramen. In form it was similar to the related Borhyaena. As with other Sparassodonts, the deciduous teeth are less reduced, only the canines and premolars changing.DistributionFossils of Prothylacinus have been found in the Friasian Río Frias Formation of Chile and the Santacrucian Santa Cruz Formation of Argentina.