Groove-toothed Bat (Phoniscus atrox)
HB: 43-46; T:37-38; FA:32-35; E: 13-13.6; HF: 7.4-7.6; W: 5g
A highly recognisable bat, due to its small size combined with exquisitely
coloured fur. The hairs are long, soft and fluffy, and on the back and head,
they are tipped with a shimmering golden colour, giving a gilded appearance. The
base of each hair is light brown to black, and on the underside of the body the
fur is paler. Golden hairs are also found along the forearm, the wing edges, the
legs, tail and feet. The nose of the gilded groove-toothed bat is simple, with
no nose leaf, and the ears are small and brown, but contain a pointed, whitish
tragus (inner ear), which has a characteristic notch at the base. A tiny groove
in each canine tooth of this species contributes to its common name. A membrane
that stretches between the hind legs, known as the interfemoral membrane,
encloses the tail. Fur: The most distinctive feature of Phoniscus atrox is the
beautiful golden brown tips to the dark brown fur. The soft fluffy hairs
actually have four bands of colours: light grey or brown near the base, then a
buffy, light brown colour, followed by a dark brown band and then the golden
tips. Teeth: Although you canít see them, the long canines have a groove running
from top to bottom, and this helps us tell the Kerivoula and Phoniscus apart,
because the canines in the Kerivoula are smooth.
Nose: The nose is simple.
Tail: The tail is very long and the tail membrane large. The bat uses this tail membrane partly to help it brake during flight, but it also acts as a sort of scoop that helps the bat to catch insects. After successfully catching an insect, he will duck his head down and grab it from the tail membrane scoop with his mouth.
Wings: The wings are a dark brown, and broadly rounded, making this bat very manoeuvrable when flying through the forest under story.
Size: Phoniscus atrox is a small bat, with an average forearm of about 34 mm and an average weight of just under 5 g, a little bit less than a nickel.
The forearm, legs, tail and feet are also thinly covered with fine hairs of gold.
Ears: The ears are funnel shaped like the Kerivoula to which Phoniscus is closely related, and there is also a long pointed tragus, that is typically without pigment so it appears a whitish pink, in contrast to the brown ears. At the base of the tragus is a small notch; the Kerivoula donít have this, so it helps us distinguish the Phoniscus from the Kerivoula.
Listening for the returning echo of their shouts, each of which lasts just 3 milliseconds, the bat is able to distinguish an insect from its surroundings, using such detail as the movement of its tiny, beating wings. As it approaches the insect the speed of its echolocation pulses quickens, to give pinpoint precision for the capture of its prey.
This species is known to occur in Peninsular Malaysia,
southern Thailand, Sumatra (Indonesia), and Sabah in Malaysian Borneo. It
is found below 400 m asl. This species may be more widespread and common than is
Indonesia (Kalimantan, Sumatera); Malaysia (Sabah, Sarawak); Thailand
Biology and Ecology
This is a forest dependent species. Lekagul and McNeely (1977) reported that the
type specimens were found roosting in an abandoned bird's nest (broadbill) in
heavy forest on the bank of a river. A recent collection was found in Thailand
in disturbed forest at 150 m asl which was adjacent to a large patch of pristine
evergreen forest (Thong et al. 2006).
With a small body and short, rounded wings, the gilded
groove-toothed bat has a high degree of flight control, enabling it to pass
nimbly amongst the leaves and branches of the forest. It feeds on flying
insects, detecting their presence with ultrasonic shouts and listening for the
returning echo. As it approaches the insect the speed of its echolocation pulses
quickens, to give pinpoint precision for the capture of its prey.
Little is known about the breeding habits of this species, but pregnancy has been recorded in April, August and October, and lactation has been noted in January, May, June and October
Deforestation due to logging, agriculture, plantations
and forest fires represents a major threat to this species.
This species is known from protected areas (Thong et al. 2006). It also appears on a checklist for the Bukit Barisan National Park in South Sumatra (O'Brien and Kinnaird 1996), but this record is questionable.