Old World sucker-footed bats

(Myzopodidae)

Class Mammalia

Order Chiroptera

Suborder Microchiroptera

Family Myzopodidae

Thumbnail description
A small bat, characterized by horseshoe shaped sucker-like pads on the thumb and soles of the feet; the ears are separate and large, each with a mushroom-like tragus, comprising a kidney-shaped fleshy expansion surmounting a short stalk; upper lip extends significantly beyond the lower; the pelage is moderately dense and mid-brown to golden brown, with some russet tinges

Size
Head and body length 2.3 in (57 mm); tail length 1.9 in (48 mm); forearm 1.9–2.0 in (47–50 mm); weight 0.3 oz (8 g)

Number of genera, species
1 genus; 1 species

Habitat
Primary and secondary rainforest of eastern Madagascar, also agricultural land and urban areas

Conservation status
Vulnerable

Distribution
Endemic to Madagascar

Evolution and systematics

Although restricted to Madagascar today, Myzopoda has been found as a fossil in the early Pleistocene deposits of Olduvai 1 in Tanzania on mainland Africa. The Old World sucker-footed bat (Myzopoda aurita) was described in 1878 and was originally included in the family of Old World evening bats, the Vespertilionidae. Subsequently, in 1904, it was transferred into a separate family, the Myzopodidae. It resembles the New World sucker-footed bats, Thryopteridae, of Central and South America, and the humerus and shoulder joint have a similar structure to this latter family and to the New World funnel-eared bats, the Natalidae. It has been included in the superfamily Nataloidea, which in addition to the Myzopodidae, includes the Natalidae, Furipteridae, and Thryopteridae. Recent molecular studies have challenged the monophyletic origin of the Nataloidea, suggesting that the Myzopodidae is not a sister taxon to the other families but evolved at a much earlier date as a distinct lineage that cannot satisfactorily be grouped with any other bat family.

The taxonomy for this species is Myzopoda aurita Milne-Edwards and A. Grandidier, 1878, Madagascar.

Physical characteristics

A small bat, characterized by the presence of conspicuous horseshoe shaped sucker-like pads on the thumb and soles of the feet. The ears are separate and large, some 1.18–1.38 in (30–35 mm) in length. Each ear has a tragus, which is fused along its anterior edge to the pinna; the meatus is partly closed by this conspicuous mushroom-shaped process, which comprises a kidney-shaped fleshy expansion surmounting a short stalk. The upper lip extends significantly beyond the lower. The pelage is moderately dense and mid-brown to golden brown, with some russet tinges. For this reason, the bat is also known as the golden bat. The ears are very large, and the thumb is quite small and has a vestigial claw. The toes of the feet have only two phalanges and are syndactylous (joined together) for much of their length. The tail projects noticeably beyond the free edge of the interfemoral membrane. The skull is short, broad, and rounded. The tympanic bullae and cochleae are rather large but not peculiar in structure. The hamular processes are unusually long. There are 38 teeth, including two pairs of upper and three pairs of lower incisors, one pair of upper and lower canines, three pairs of upper and lower premolars and three pairs of upper and lower molars.

Distribution

It is now restricted to Madagascar, where it is primarily found on the east coast, in the former rainforest region. In addition, there has been one record from the west of the country: Mahajanga. There are fewer than 20 locality records. These stretch the full length of the eastern sea board of Madagascar.

Habitat

Its preferred habitat is thought to be primary and secondary rainforest of eastern Madagascar. It is also known to frequent paddies, marshlands, vanilla plantations, streams, and even urban areas.

Behavior

Very little is known of its behavior. One individual was mist-netted over a small stream, another in a vanilla plantation, and one in a sparsely forested area over a path close to a stream. In August 1992, a single individual was caught in a mist net set at 6:55 p.m., about one hour after sunset. It has also been recorded, based on acoustic identification, flying over urban areas. A single specimen was collected from the unrolled leaf of a traveler's palm, Ravenala madagascariensis (Musaceae). Like the New World disk-winged bats, the Thryopteridae, it probably roosts in a variety of palm species and other similar types of vegetation (for example Araceae). It roosts with its head uppermost and uses its stiff projecting tail as a prop. The suction pads present on the thumbs and feet allow it to cling to smooth vertical surfaces, such as the leaves of Ravenala. The pads contain rows of glands that secrete directly onto the surface of the suction pads. This increases the adhesion and allows the whole body weight to be supported. Its flight is highly maneuverable.

Feeding ecology and diet

The species possesses a complex echolocation system and produces remarkably long calls, which are presumably suited to its feeding habits. It emits complex frequency modulated (FM) echolocation calls, which are composed of two to four distinct elements of increased amplitude and long call durations. Due to different numbers of elements and the presence of up to four harmonics, the call structure is highly variable. The second harmonic is the strongest. It decreases from 42 to 24 kHz with a shallow FM sweep (about 0.6–0.9 kHz/ms) during the first three elements and a steep FM sweep (about 2 kHz/ms) during the fourth element. Analysis of fecal pellets of a single individual showed that its diet included moths (Microlepidoptera). It is not known whether this is a specialization or an abundance of this type of prey at that particular moment. It has been observed to spend relatively long periods of time, probably feeding, over freshly dug and planted paddy fields and also within forest clearings in primary rain-forest. However, no feeding buzzes were recorded.

Reproductive biology

Nothing is known of its breeding biology, although a female collected on 13 August 1992 had well developed nipples.

Conservation status

Vulnerable. It is generally considered to be rare, based on the very few specimens that have been collected. However, recent studies based on ultrasonic evidence have found it to be widespread in the Antongil Bay area of the Masoala Peninsula in northeast Madagascar. Here it inhabits areas not only close to forest but also urban areas. This suggests that further studies elsewhere in Madagascar using bat detectors may find larger populations than previously thought. In general, loss of forest is thought to be a probable threat but the species is still poorly known and it is therefore difficult to determine accurately its conservation requirements. If the species does roost primarily in the traveler's palm, then the bat may be more common than currently thought as this plant is widespread in primary and secondary forest. Bats, including this species, are not protected in Madagascar.

Significance to humans

This species has little significance to humans. Like many bat species it probably helps to reduce agricultural pests by feeding on potentially harmful insects.

Resources

Books

Garbutt, N. Mammals of Madagascar. New Haven, CT: Yale University Press, 1999.

Hutson, A. M., S. P. Mickleburgh, and P. A. Racey. Microchiropteran Bats: Global Status Survey and Conservation Action Plan. IUCN/SSC Chiroptera Specialist Group. Gland, Switzerland and Cambridge, UK: IUCN, 2001.

Periodicals

Gopfert, M. C., and L. T. Wasserthal. "Notes on Echolocation Calls, Food and Roosting Behaviour of the Old World Sucker-footed Bat Myzopoda aurita (Chiroptera, Myzopodidae)." Zeitschrift für Säugetierkunde 60, no. 1 (1994): 1–8.

Schliemann, H., and B. Maas. "Myzopoda aurita." Mammalian Species 116 (1978): 1–2.

Van Den Bussche, R. A., and S. R. Hoofer. "Evaluating Monophyly of Nataloidea (Chiroptera) with Mitochondrial DNA Sequences." Journal of Mammalogy 82, no. 2 (2001): 320–327.

Paul J. J. Bates, PhD