Proborhyaenidae is an extinct family of metatherian mammals of the order Sparassodonta, which lived in South America from the Eocene (Casamayoran) until the Oligocene (Deseadan). Sometimes it has been included as a subfamily of their relatives, the borhyaenids (as Proborhyaeninae). Body mass estimates suggest that proborhyaenids could weigh up to 150 kilograms (330 lb), making them some of the largest known metatherians. Proborhyaenid remains have been found in western Bolivia, Uruguay, southern Brazil, and the provinces of Mendoza, Salta, and Chubut, in Argentina.-