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

flying squirrel Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe (biology), tribe of 50 species of squirrels in the family (biology), family Squirrel, Sciuridae. Despite their name, they are not in fact capable of full flight i ...

endemic Endemism is the state of a species being found only 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 foun ...

Arunachal Pradesh Arunachal Pradesh (; ) is a States and union territories of India, state in northeast India. It was formed from the North-East Frontier Agency (NEFA) region, and India declared it as a state on 20 February 1987. Itanagar is its capital and la ...

northeast India Northeast India, officially the North Eastern Region (NER), is the easternmost region of India representing both a geographic and political Administrative divisions of India, administrative division of the country. It comprises eight States and ...

, where it is known from a single

zoological specimen A zoological specimen is an animal or part of an animal preserved for scientific use. Various uses are: to verify the identity of a (species), to allow study, increase public knowledge of zoology. Zoological specimens are extremely diverse. Exampl ...

collected in

Namdapha National Park Namdapha National Park is a large national park 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. It ha ...

in 1981.

Description

The Namdapha flying squirrel has reddish, grizzled fur with white above and a pale grey crown; its

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

is orangish and its underparts are white. Its cheek teeth 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, wher ...

s are unpigmented.

Septae In biology, a septum (Latin for ''something that encloses''; septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatrial sep ...

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 b ...

e and sometimes

honeycomb A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic cells built from beeswax by honey bees in their beehive, nests to contain their brood (eggs, larvae, and pupae) and stores of honey and pol ...

-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 long.

Taxonomy

The Namdapha flying squirrel first described in 1981, based on a single

collected in

. Its 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 the Ministry of Environment, Forest and Climate Change of the Government of India as a premier Indian organisation in zoological research and studies to promote the survey, explora ...

. It was the first member of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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, ...

''; in 2013, 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 re ...

(''Biswamoyopterus laoensis'') was described. In 2018, a new flying squirrel, the

Mount Gaoligong flying squirrel The Mount Gaoligong flying squirrel (''Biswamoyopterus gaoligongensis'') is a species of large, arboreal flying squirrel endemic to highland forests in southwestern China. It is the third known member of the highly elusive genus ''Biswamoyopteru ...

(''Biswamoyopterus gaoligongensis'') was discovered in China.

Distribution and habitat

The Namdapha flying squirrel is

. It inhabits tall ''

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

'' jungles, often on hill slopes in the

drainage basin A drainage basin is an area of land in which 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, ...

area of

Dihing River The 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 ...

, particularly on the western slope of

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

range in northeastern India. In April 2022, a putative Namdapha flying squirrel was recorded in Arunachal Pradesh. To prove its validity, the researchers are planning to collect fecal samples for identification of

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

Status

The Namdapha flying squirrel is listed as

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

. Its range may be restricted to a single valley, and it is threatened by

poaching Poaching is the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the huntin ...

of animals for food within the park, and possibly by

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

. It is among the 25 "most wanted lost" species that are the focus of Re:wild's "Search for Lost Species" initiative.

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