The bonobo, also historically called the pygmy chimpanzee, is an endangered great ape and one of the two species making up the genus Pan. While bonobos are, today, recognized as a distinct species in their own right, they were initially thought to be a subspecies of Pan troglodytes, because of the physical similarities between the two species. Taxonomically, members of the chimpanzee/bonobo subtribe Panina—composed entirely by the genus Pan—are collectively termed panins.