Squirrels of the World

Hylopetes winstoni 105

and Malaysia. Recent analyses of the pelage and cranioden-
tal characteristics, however, indicate a clear diff erentiation
of the three species. This taxonomic clarifi cation implies
that the Sunda Strait, between Java and southern Sumatra,
was a barrier preventing colonization of Java by H. spadiceus.
This is not unique to this species: among 25 species of sciu-
rids found on Sumatra, only nine also occur on Java. In con-
trast, the Malacca Strait, between Sumatra and the Malay
Peninsula, appears not to have been a barrier either for H.
spadiceus or for 19 other sciurids found on Sumatra. Like-
wise, neither the Isthmus of Kra on the Malay Peninsula,
nor the South China Sea, separating the Malay Peninsula
and the island of Borneo, has served as a dispersal barrier
for H. spadiceus. One unidentifi ed nematode and Capillaria
hepatica are reported from H. spadiceus.

general references: Ahl 1987; Corbet and Hill 1992;
Duckworth and Hedges 2008c; Dunn et al. 1968; Liat et al.
1977; Meijaard 2003a; Rasmussen and Thorington 2008; R. W.
Thorington and Hoff mann 2005.

Hylopetes winstoni (Sody, 1949)

Sumatran Flying Squirrel

description: This is a small fl ying squirrel, with tufts of
stiff hairs—directed upward and backward—in front of and
above the ears and on the cheeks.

size: Male—HB 142.0 mm; T 143.0 mm.
Sex not stated—HB 142.0 mm.

distribution: The Sumatran fl ying squirrel is known only

from the type locality: “Baleq, E. Atjeh [= Aceh], in northern

Sumatra, 1200 m” (Indonesia).

geographic variation: None.

conservation: IUCN status—data defi cient. Population

trend—no information.

habitat: The preferred habitat for this species is reported

to be primary forest, at elevations of 1000 to 1500 m, but

details on its habitat preferences are lacking.

natural history: Information on this critically endan-

gered species, found only on Sumatra, is based on a single

specimen. No information is available on its population bi-

ology or ecology, but this species is considered highly

threatened by habitat loss, due to deforestation. More work

is required to clarify the distinction between H. winstoni and

H. bartelsi.

general references: Ruedas et al. 2008c.

Hylopetes spadiceus. Photo courtesy Nick Baker, http://www.eco
logyasia.com.