Babyrousa bolabatuensis

The Bola Batu babirusa (Babyrousa bolabatuensis) is a species of babirusa from the Indonesian island of Sulawesi. It was first described in 1950 as a subspecies of Babyrousa babyrussa, at a time when that was the only recognized babirusa, and Colin Groves and Erik Meijaard raised it to full species rank in 2002. Its standing is unsettled. It is known for certain only from subfossil remains found in the southern arm of Sulawesi, where living animals are now likely extinct. A single skull from central Sulawesi led some authors, including the third edition of Mammal Species of the World, to treat central Sulawesi babirusas as living Bola Batu babirusas, but the most recent major review saw similarities to the Togian babirusa and concluded that the skull represents an undescribed taxon. The IUCN Red List provisionally treats the name as a synonym of the northern Sulawesi babirusa, Babyrousa celebensis, until more specimens settle the question.