The Namdapha flying squirrel (''Biswamoyopterus biswasi'') is an

arboreal Arboreal locomotion is the Animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. Th ...

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

flying squirrel Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe of 50 species of squirrels in the family Sciuridae. Despite their name, they are not in fact capable of full flight in the same way as birds or bats, but they ar ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...

northeast India , native_name_lang = mni , settlement_type = , image_skyline = , image_alt = , image_caption = , motto = , image_map = Northeast india.png , ...

, where it is known from a single

specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository ...

collected in

Namdapha National Park Namdapha National Park is a large protected area in Arunachal Pradesh of Northeast India. The park was established in 1983. With more than 1,000 floral and about 1,400 faunal species, it is a biodiversity hotspot in the Eastern Himalayas. The ...

in 1981. No population estimate is available for ''B. biswasi'', but the known habitat is tall ''

Mesua ferrea ''Mesua ferrea'', the Ceylon ironwood, or cobra saffron, is a species in the family Calophyllaceae. This slow-growing tree is named after the heaviness and hardness of its timber. It is widely cultivated as an ornamental due to its graceful sha ...

'' jungles, often on hill slopes in the

catchment A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the ...

area of

Dihing River Dihing or Burhi Dihing (Dihong = wide river ) is a large tributary, about long, of the Brahmaputra River in Upper Assam in northeastern India. The river originates at above sea level in the Eastern Himalayas (the Patkai Hills) in Arunachal Pr ...

(particularly on the western slope of

Patkai The Pat-kai (Pron:pʌtˌkaɪ) or Patkai Bum ( Burmese: ''Kumon Taungdan'') are a series of mountains in the Indo-Myanmar border falling in the north-eastern Indian states of Arunachal Pradesh, Nagaland and Upper Burma region of Myanmar. They ...

range) in northeastern India. It was the sole member in the genus ''

Biswamoyopterus ''Biswamoyopterus'' is a genus of rodent in the family Sciuridae. It contains three known species of very large flying squirrels, with '' B. laoensis'' being among the longest of all squirrels. They are distributed in forests in northeast India, ...

'' until the description of the

Laotian giant flying squirrel The Laotian giant flying squirrel (''Biswamoyopterus laoensis'') is an arboreal, flying squirrel endemic to Laos. It was the second described member in the genus '' Biswamoyopterus'', after being first collected in September 2012 by scientists ...

(''Biswamoyopterus laoensis'') in 2013. In 2018, Quan Li from the Kunming Institute of Zoology at the Chinese Academy of Sciences discovered a new squirrel in the same genus while studying specimens in their collection, called the Mount Gaoligong flying squirrel (''Biswamoyopterus gaoligongensis''), based on the region it was discovered in.

Description

''Biswamoyopterus biswasi'' has reddish, grizzled fur with white above. Its crown is pale grey, its

patagium The patagium (plural: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flight. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosaurs ...

is orangish and its underparts are white. The cheek teeth of ''B. biswasi'' are simple, and its

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whe ...

s are unpigmented. Septae are multiple in

auditory bulla The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic ...

e and sometimes

honeycomb A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic Beeswax, wax cells built by honey bees in their beehive, nests to contain their larvae and stores of honey and pollen. beekeeping, Beekee ...

-shaped with 10 to 12 cells in it. It measures from head-to-

vent Vent or vents may refer to: Science and technology Biology *Vent, the cloaca region of an animal *Vent DNA polymerase, a thermostable DNA polymerase Geology *Hydrothermal vent, a fissure in a planet's surface from which geothermally heated water ...

and has a long tail. The hindfoot is and the ear is . The scientific name commemorates

Biswamoy Biswas Biswamoy Biswas (2 June 1923 – 10 August 1994) was an Indian ornithologist who was born in Calcutta, the son of a professor of geology.Mayr, E. (2000) "In Memoriam: Biswamoy Biswas, 1923–1994." ''The Auk'' 117(4):103PDF/ref> In 1947, he was ...

, director of the

Zoological Survey of India The Zoological Survey of India (ZSI), founded on 1 July 1916 by Government of India Ministry of Environment, Forest and Climate Change, as premier Indian organisation in zoological research and studies to promote the survey, exploration and r ...

Status

The Namdapha flying squirrel is listed as critically endangered by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

. It is known from a single specimen collected in 1981 in

. Its range of the Namdapha flying squirrel may be restricted to a single valley and it is threatened by poaching of animals for food from within the park, and possibly by

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

. It is among the 25 "most wanted lost" species that are the focus of Global Wildlife Conservation's "Search for Lost Species" initiative. There are several later reports of sightings by tourists and local researches, but a review by scientists specialising in flying squirrels found that most—if not all—have been the result of confusion with other, more common species that occur in Namdapha National Park, especially the rather similar ''candidula'' red giant flying squirrel (''Petaurista petaurista candidula'').

References

{{Taxonbar, from=Q1482523 Biswamoyopterus Endemic fauna of India Rodents of India Environment of Arunachal Pradesh Critically endangered fauna of Asia Mammals described in 1981 Species known from a single specimen