128 Petinomys vordermanni(Indonesia). Populations are reported from some of the east-
ern islands of Sumatra (Indonesia) as well. Although its dis-
tribution is considered highly fragmented, this may result
from it being overlooked in surveys because of its arboreal
and nocturnal behavior.geographic variation: None.conservation: IUCN status—vulnerable. Population
trend—declining.habitat: This species is reported to prefer lowland rainfor-
est, and it is considered exclusively arboreal, restricting all
of its activity to the canopy or subcanopy. It has been re-
ported from rubber plantations, forests bordering swamps,
and primary forests following selective timbering.natural history: Little is known about the behavior and
population ecology of this species. It is considered threat-
ened by deforestation for agriculture and timber. P. vorder-
manni is a defi nitive host for the ancanthocephalan Monili-
formis moniliformis.general references: Deveaux et al. 1988; Francis and
Gumal 2008d; W. P. Harris 1944; Hautier et al. 2009; Mei-
jaard 2003b; Muul and Liat 1971; Muul and Thonglongya
1971; Nakagawa et al. 2007; R. W. Thorington, Pitassy et al.
2002.Pteromys G. Cuvier, 1800
This genus has two species.
Pteromys momonga Temminck, 1844
Japanese Flying Squirrel
description: The Japanese fl ying squirrel is about 15 per-
cent of the size of the Japanese giant fl ying squirrel (Petau-
rista leucogenys) and 25 percent larger than Glaucomys sabri-
nus. Its dorsum is light brown or grayish brown; its belly
and the ventral surface of the patagium (“wing”) are white.
The head is robust and rounded anteriorly.
size: Female—HB 162.8 mm; T 140.5 mm.
Male—HB 154.0 mm; T 136.0 mm.
Sex not stated—HB 170.0 mm; T 120.0 mm; Mass 151.8 g.
distribution: P. momonga is endemic to 3 of the 12 islands
in the Japanese Archipelago: Honshu, Shikoku, and Kyushu.
geographic variation: None.