The Bougainville monkey-faced bat or Bougainville flying monkey (Pteralopex anceps) is a megabat endemic to Bougainville Island of Papua New Guinea and Choiseul Island of the Solomon Islands in Melanesia. It inhabits mature forests in upland areas, within the Autonomous Region of Bougainville and Bougouriba Province. Discovery and taxonomy It was first collected by English naturalist Albert Stewart Meek in April 1904 from Bougainville Island. That specimen was later used by Danish zoologist Knud Andersen in 1909 to describe a new species. The species name anceps comes from Latin, meaning "double-headed" or "having two heads." This could possibly be a reference to it being the second described member of Pteralopex, or that it had characters similar to both Pteralopex and Pteropus, especially the Bonin flying fox. In 1954, it was listed as a subspecies of the Guadalcanal monkey-faced bat. In 1978, it was once again listed a separate species. Some have considered it synonymous with the greater monkey-faced bat, which is found in the same range, while others maintain them as separate species. Description It is the largest member of its genus, Pteralopex. Their forearms are long. They can be identified by their short ears, mostly obscured by their fur. They have black fur on their heads and backs. Their chests have a white or yellow patch. The fur is long, with individual hairs approximately Unlike the Guadalcanal monkey-faced bat, the tibia is fully furred. They have a robust skull morphology, with thick zygomatic arches and high sagittal crests. Their dental formula of . It is thought that their eyes are red or orange in color like other members of their genus. They lack tails. Males and females are similar in body size. Biology One was observed roosting in a fig tree. They have been observed roosting alone and within groups. Their diet is unknown, but specimens in museums have extensive tooth wearing, suggesting that they might feed on hard, abrasive fruits. Habitat and range The majority of museum specimens were collected from cloud forests at or higher above sea level. It is not thought to occur in coastal forests. It had not been seen on Bougainville Island since 1968, until they were again sighted in 2016. It was last seen on Choiseul Island in 2008. Conservation In 1992, this species was feared extinct because it had not been seen despite research expeditions in the area. However, a research expedition