Eupetaurus tibetensis, 2021

Jackson, Stephen M., Li, Quan, Wan, Tao, Li, Xue-You, Yu, Fa-Hong, Gao, Ge, He, Li-Kun, Helgen, Kristofer M. & Jiang, Xue-Long, 2021, Across the great divide: revision of the genus Eupetaurus (Sciuridae: Pteromyini), the woolly flying squirrels of the Himalayan region, with the description of two new species, Zoological Journal of the Linnean Society 194 (2), pp. 502-526 : 15-16

EUPETAURUS TIBETENSIS JACKSON, HELGEN, Q. LI & JIANG SP. NOV.

Suggested common name: Tibetan woolly flying squirrel.

Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: 19DA79D4-7E20-4EB6-A1C7-2C22C6F21D58

Holotype: NML 19524, adult, skin and skull, collected in ‘ Tibet’ . Sequences of Cytb for this specimen are deposited in GenBank (no. AY 331673 ).

This specimen was first discussed by Anderson (1879), who left it taxonomically unidentified. When describing E. cinereus as a new genus and species, Thomas (1888) speculated that Anderson’s Tibetan specimen was also a Eupetaurus , a point later confirmed by Jentink (1890), who figured the skull of this specimen. Little is known about the collection details for this specimen other than that it is ‘said to be from Tibet’ ( Jentink, 1890: 143). Corbet & Hill (1992: 314) noted that the association of the skull and skin for this specimen suggest that ‘it is not a trade skin’ (i.e. it is probably a wild-collected animal). To us, this specimen, when considered alongside the paratype skin obtained in a market in the Tibetan town of Gyantse (also spelt Gyangze, 江ở) in 1909, establishes the historical occurrence of this species in the south-central portion of the Tibetan Plateau (see below).

Paratype: BMNH 23.11 .10.2, skin, with partial skull in situ inside the skin, probably female by examination of the specimen, ‘bought in Gyantze Bazaar’ (earlier tag reads ‘ Gyantsi Bazaar’ ), Tibet, collected in June 1909 by Colonel F. M. Bailey [Bailey was British Trade Agent at Gyantsi and Chumbi (¤丕) in Tibet at that time; Bailey, 1945] .

Referred specimens: Two specimens from the state of Sikkim in north-eastern India: BMNH 88.9.29.1, skin, with skull fragments removed from skin (anterior of mandibular rami, preserving incisors; anteriormost cranium preserving incisors, premaxillae and nasals), from ‘ Sikkim?’, received from W. T. Blanford from the ‘Mandelli collection’ (thus apparently collected by L. Mandelli); and ZSI 19103, skin, from ‘North Sikkim, alt. 3000 m’ ( Agrawal & Chakraborty, 1970), elevation also reported as ‘9000 feet’ ( Zahler & Woods, 1997).

Type locality: Labels associated with the holotype indicate only that it was collected in ‘Tibet’. The paratype specimen at BMNH was obtained from the bazaar at Gyantse (as ‘ Gyantsi Bazaar’). Here , we accordingly fix the type locality as ‘vicinity of Gyantse Town’ , Tibet (= Xizang) . Gyantse is situated at an elevation of 4000 m a.s.l. in the Nyang Chu Valley (年 楚河â), Shigatse (H喀Nj), southern Tibet .

Diagnosis: Eupetaurus tibetensis differs from E. cinereus in having more saturated brown pelage, tinged with reddish tones (typically more clear grey in E. cinereus ) and from E. nivamons in having a black tail tip that is much shorter (approximately half the length of the tail in E. nivamons ). The rostrum is similar to E. cinereus and narrower than E. nivamons . The temporal ridges are convergent posteriorly, as in E. cinereus , rather than parallel, as in E. nivamons . The cusps and ridges of cheek teeth are more robust than in E. nivamons but less robust than in E. cinereus . Upper cheek teeth are heart shaped, as in E. cinereus , and differ from the rounded shape in E. nivamons . Lower molars are subrectangular, as in E. nivamons , and differ from the subsquare ones in E. cinereus , with only one long anterior fosettid per lower molar (two short anterior fosettids in E. nivamons ; one short anterior fosettid in E. cinereus ). Overall, the dentition of E. tibetensis resembles that of E. cinereus more than E. nivamons , but the external appearance of E. tibetensis is similar to E. nivamons .

Descriptive notes: In the available specimens of E. tibetensis , overall body size is similar to E. cinereus , with a head–body length of 468 mm in the holotype (with the imperfect, broken tail measuring 350 mm). The dorsal pelage is brownish grey, with less extensive frosting of the fur tips than seen in E. cinereus , and with reddish tones sometimes evident along the midline of the dorsum, on the rump and on the proximal portion of the tail. The underparts are greyish, washed with yellow. The dorsal surfaces of the forefeet and hindfeet are brown. The tail is bushy and cylindrical, with coloration similar to the body, except for a short black tip. The skull and dentition are as described above for the genus Eupetaurus and diagnosis of the species.

Etymology: The species name is derived from its occurrence in Tibet, where the holotype and paratype originated.

Distribution: Records of occurrence that we attribute to E. tibetensis originate from elevations of 2700–4000 m a.s.l. in Tibet (= Xizang) in China, Sikkim in India and (more tentatively) from Bhutan. This species is known for certain from two specimens from Tibet and two specimens from Sikkim, discussed above. Eupetaurus has also been reported from Bhutan ( Wangchuk et al., 2004), and given the proximity of Bhutan to vouchered records from south-central Tibet and north Sikkim, we suggest that these Bhutanese observations are likely to represent E. tibetensis . We are not aware of vouchered specimens or specific published records from Bhutan, only general statements about its occurrence: Wangchuk et al. (2004) noted that it was found in coniferous, rhododendron and subalpine forests> 2700 m a.s.l.; Srinivasulu & Srinivasulu (2012) specified that it was known from western Bhutan; and Rinchen (2009) suggested that it might occur in Jigme Dorji National Park in north-western Bhutan. No records of Eupetaurus have yet been noted from Nepal ( Mitchell, 1979; Thapa et al., 2016).

In summary, we suspect that the distribution of E. tibetensis comprises the far southern portion of the central Tibetan Plateau and the northern slopes of the Himalayas in Sikkim and Bhutan ( Fig. 10 ).

Natural history: Currently, there is little known about the ecology of E. tibetensis . Commencing research on this species to understand its distribution, ecology and conservation status is an urgent need.

Conservation: The conservation status of E. tibetensis remains unknown. We recommend an IUCN Red List categorization of Data Deficient for the species. Surveys are needed to determine the extent of its distribution, including whether it occurs in protected areas, such as Jigme Dorji National Park in Bhutan, and if it is facing particular threats, such as deforestation or hunting.

Figures

Figure 10. Known localities of the three species of Eupetaurus.