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Allocebus trichotis
(Ganther, 1875) (Ganther pl15)

IUCN Red List Status (1996):

Critically Endangered/A1c, +2abc

Description

The species was initially classified in the genus Cheirogaleus (Ganther, 1875), but is now considered to be in its own genus (Petter-Rousseaux and Petter, 1967; Tattersall, 1982; Jenkins, 1987). The pelage coloration is rather uniform gray, rosy brownish-gray dorsally and whitish/yellowish gray ventrally (see: [Picture] Skins M. murinus & A. trichotis). The tail is reddish brown and longer than the body. There are narrow dark rings around the eyes. Its ears are short and concealed in fur but long wavy hairs form the ear tufts from which this lemur gets its common name. Its nails are keeled, except on the hallux, but the apex of the nails are rounded, not pointed (Meier and Albignac, 1991).
Measures of specimen of the Museum national d'Histoire naturelle are: length (head and body): 133 mm; tail length: 170 mm; length of hand: 22 mm; length of hind foot: 37 mm (For more measurements see Rakotoarison et al., 1997). The length of the tail of this specimen does not correspond with the tail length of the holotype. The measurements given by Ganther, 1875 are 152 mm for the head and body and 149 mm for the tail, while the author emphasizes that the tail is shorter than the body. In contrary, the specimen measured by Petter has a much longer tail. Five of the seven animals measured by Rakotoarison et al., 1997 have a longer tail than head/body length. One might suppose that the specimen studied by Ganther might have been damaged. The adult female of this species caught by Meier and Albignac, 1991 weighed 80 g; the adult male weighed 75 g. A juvenile of unknown sex weighed 58 g. Body length of the female was 145 mm, tail length was 165 mm; body length of the male was 125 mm; tail length was 195 mm.

Distribution

Until its rediscovery in 1989, the Hairy-eared Dwarf Lemur was known from only five museum specimens. The holotype was collected by Crossley in 1874, but the information on its label, stating that it was collected in S. Madagascar, differs from Ganther's (1875) statement that it came from the area between 'Tamantave' (i.e. Toamasina, on the east coast) and 'Murundava' (i.e. Morondava, on the west coast) (Tattersall, 1982). The provenance of the two specimen collected by Humbolt around 1880 is unknown (Tattersall, 1982). A fourth specimen has recently been discovered in the collections of the Naturhistoriska Riksmuseet in Stockholm by G. H. Albrecht (pers. comm. to P. Jenkins, 1987). No date is given for this specimen. Its locality is either 'Nanaka' or 'Namaka' (Jenkins, 1987). Jenkins suggests that this may be equivalent to Nanakara (24°17'S, 45°53'E), but as this village is not in an area of rain forest, it seems an unlikely site for the Hairy-eared Dwarf Lemur ever to have been located. Peyrieras, in 1965, captured the fifth specimen in Andranomahitsy forest, near the village of Ambavala, 16 km from the town of Mananara, which is on the east coast of Madagascar (Peyrieras pers. comm. to Meier and Albignac, 1991). In august 1975, thanks to the 'Fondation Ligabue' and to Peyrieras, who already collected a living animal, a seach for A. trichotis was undertaken. For 10 days, an attempt was made to find an animal in the remaining forest west of Mananara, particularly at Andranomahitsy, where the first animal was found. A nocturnal, systematic exploration with great care for the forest unfortunately did not result in finding a trace of the species. Only numerous individuals of Microcebus were found at the border of the forest and in bushes. However, it was relocated there by Bernhard Meier and Roland Albignac early in 1989.
Meier and Albignac, 1991 consider that the distribution of this species may be restricted and patchy. They report seeing a number of Allocebus in the area around Mananara. Meier saw one individual close to the village of Ambalava (16°12'S, 49°37'E) and one at 16°26'S, 49°38'E, 1.5 km from the Bedinta mountain, which is 34 km from Mananara. In addition, three individuals were caught near the village of Andranombazaha (16°28'S, 49°38'E).
Tattersall, 1982 suggests that the species once occurred quite widespread in the eastern humid forests, but the paucity of either specimens or sightings makes it difficult to confirm this.
The small amount of information accompanying the type and the specimen of the collection of the national museum at Paris suggests that the animals come from the middle part of the eastern forest.
It is however possible that this animal is more common as one might think. Its rarity might be due to its ecological particularity. It is likely that the animal only lives in the primary, undisturbed forest, because all systematic collecting around villages only yielded Microcebus.
Rakotoarison et al., 1997 published recent sightings confirmed with caught animals in Mananara, Zahamena and Vohidrazana and unconfirmed sightings at Cap Masoala and Anjanaharibe-Sud.

Population

Numbers are not known, but Tattersall, 1982, considered this the rarest of the surviving lemurs and one which probably never existed at high densities. Meier and Albignac, 1991 state that the population density may be very low. Its numbers are almost certainly declining as the eastern rain forests are reduced in size (Richard and Sussman, 1975; Richard and Sussman, 1987). Meier and Albignac, 1991 also consider that its numbers are probably declining.

Habitat and ecology

Comparatively, little is known about this species but it appears to occur only in lowland rain forest. One of the individuals seen by Meier occurred in degraded primary lowland forest, while the other was seen in virgin primary forest (Meier and Albignac, 1991). The three captured individuals all were taken in primary lowland forest (Meier and Albignac, 1991). It is a nocturnal species, becoming active at dusk and remaining so until the very first light of dawn (Meier and Albignac, 1991). It jumps a lot, in a manner similar to Microcebus rather than Cheirogaleus (Meier and Albignac, 1991). There is no information on the diet of the Hairy-eared Dwarf Lemur in the wild. Meier and Albignac, 1991 suggest that this species may feed on nectar. It has a very long tongue, like Phaner and, in captivity, eats honey. Caged animals ate locusts, which were jumped on and caught with both hands; fruit was also eaten (Meier and Albignac, 1991). In May, Allocebus has a considerable fat deposit, which is not stored in the tail, as in Cheirogaleus, but is distributed all over the body (Meier and Albignac, 1991). Local people reported that they did not see any active Hairy-eared Dwarf Lemurs between May and September and it could be that they are in some type of hibernation during that time of year (Meier and Albignac, 1991). In captivity, activity is drastically reduced from June to September (Meier and Albignac, 1991). The animals are usually found sleeping in tree holes. One individual was caught in a hole in a small dead tree that was broken off 4 m above the ground (Meier and Albignac, 1991). This was a juvenile male and there were two other individuals in the same hole.

Local people reported that usually two or three individuals are found in a tree hole but that up to six animals could be together (Meier and Albignac, 1991). It is possible that infants are born in January or February as some Malagasy tree loggers saw half grown individuals in March (Meier and Albignac, 1991).

The behavior of this rare animal is in the first place observed in captivity at Tananarive by R. Albignac et al., 1991, who analyzed its postures and movements, its rhythm, its diet, its reproduction and its communication.
Original description:

Chirogaleus trichotis Ganther, 1875, Proc. Zool. Soc. London: 78.

Common names:

Hairy-eared Dwarf Lemur [English]
Allocèbe [French]
Chirogale aux oreilles poilues [French]
Baschelohrmaki [German]
Pluimoorkatmaki [Dutch]
Tsidy ala [Malagasy] (meaning mouse lemur of the big forest)
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Mammalia
Subclass Theria
Infraclass Eutheria
Order Primates
Suborder Strepsirhini
Infraorder Lemuriformes
Superfamily Lemuroidea
Family Cheirogaleidae
Subfamily Cheirogaleinae
Genus Allocebus
Species trichotis
Threats

The main threat to this species must be destruction of the rain forest for agriculture and fuel and by timber companies. It has recently been estimated that 111,000 ha of eastern rain forest have been cleared each year between 1950 and 1985, most of which being the lowland forest (Green and Sussman, 1990). If the cutting continues, forests on only the steepest slopes will survive the next thirty-five years (Green and Sussman, 1990) and this will probably mean the extinction of Allocebus (if it does, indeed, is restricted to the lowland rain forest).

Conservation measures

There are no measures suggested specifically for conserving the Hairy-eared Dwarf Lemur and, until more is known about its ecology and range, none can be made. Its chances of survival will be increased by preservation of the eastern rain forest. An area around Mananara, the only known location of Allocebus, has been proposed as a Biosphere Reserve (Nicoll and Langrand, 1989). It is suggested that the protected area should have the status of a National Park and that a buffer zone be set up surrounding it (Nicoll and Langrand, 1989). Extensive surveys are needed to try to locate any remaining populations of the Hairy-eared Dwarf Lemur. See also Rakotoarison et al., 1997.
Captive breeding

Up til present, five animals had been kept in captivity except the one collected by Peyrieras, which he had for only a few days (Petter et al., 1977). There were two individuals at the Parc Botonique et Zoologique de Tsimbazaza (Rakotoarison et al., 1997) and according to ISIS, 1999 there is still one in Parc Zoologique in Paris.

ISIS, 1999: Paris, 1.