The Bangka slow loris (Nycticebus bancanus) is a strepsirrhine primate and a species of slow loris that is native to southwestern Borneo and the island of Bangka. Originally considered a subspecies or synonym of the Bornean slow loris (N. menagensis), it was promoted to full species status in 2013 when a study of museum specimens and photographs identified distinct facial markings, which helped to differentiate it as a separate species. It is distinguished by the crimson red fur on its back, light-colored facial features, as well as the shape and width of the stripes of its facial markings.
As with other slow lorises, this arboreal and nocturnal species primarily eats insects, tree gum, nectar, and fruit and has a toxic bite, a unique feature among primates. Although not yet evaluated by the International Union for Conservation of Nature (IUCN), it is likely to be listed as "Vulnerable" or placed in a higher-risk category when its conservation status is assessed. It is primarily threatened by habitat loss and the illegal wildlife trade.
N. bancanus is a strepsirrhine primate, and species of slow loris (genus Nycticebus) within the family Lorisidae. Museum specimens of this animal had previously been identified as the Bornean slow loris (Nycticebus menagensis), first described by the English naturalist Richard Lydekker in 1893 as Lemur menagensis.[3] In 1906, Marcus Ward Lyon, Jr. first described N. bancanus, noting that it was a "well-marked offshoot of N. borneanus, which he also first described in the same publication.[4] By 1953, all of the slow lorises were lumped together into a single species, the Sunda slow loris (Nycticebus coucang).[5] In 1971, that view was updated by distinguishing the pygmy slow loris (N. pygmaeus) as a species, and by further recognizing four subspecies, including N. coucang menagensis, the Bornean slow loris.[6][7] From then until 2005, N. bancanus was considered a synonym of the Bornean slow loris,[8] which was elevated to the species level (as N. menagensis) in 2006, when molecular analysis showed it to be genetically distinct from N. coucang.[9]
A 2013 review of museum specimens and photographs attributed to N. menagensis resulted in elevating two of its former subspecies to the species N. bancanus and N. borneanus.[10] Additionally, N. kayan emerged as a new species, which had previously been overlooked. All newly recognized or elevated species showed significant differences in their "face mask"—the coloration patterns on their face.[10]
Like other slow lorises, it has a vestigial tail, round head, and short ears.[11] It has a rhinarium (the moist, naked surface around the nostrils of the nose) and a broad, flat face with large eyes.[12] Like N. menagensis, this and all other Bornean species lack a second upper incisor, which distinguishes them from other slow lorises.[13] On its front feet, the second digit is smaller than the rest; the big toe on its hind foot opposes the other toes, which enhances its gripping power. Its second toe on the hind foot has a curved grooming claw that it uses for scratching and grooming, while the other nails are straight.[12] It also possesses a specialized arrangement of lower front teeth, called a toothcomb, which is also used for grooming, as with other lemuriform primates.[14] On the ventral side of its elbow, it has a small swelling called the brachial gland, which secretes a pungent, clear oily toxin that the animal uses defensively by wiping it on its toothcomb.[15]