Microcebus rufus (Lesson, 1840)

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cheirogaleidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 28-65 : 55

13.

Rufous Mouse Lemur

Microcebus rufus

French: Microceébe roux / German: Brauner Mausmaki / Spanish: Lémur raton castano

Other common names: Brown Mouse Lemur, Eastern Rufous Mouse Lemur

Taxonomy. Gliscebus rufus Lesson, 1840 ,

Madagascar.

Strictly speaking, the name M. rufus is invalid for this species, as it was first given to a specimen of the Gray Mouse Lemur ( M. murinus ) by Wagner in 1839. It was hence unavailable as a name for the Rufous Mouse Lemur when Lesson described the latter just one year later, in 1840. This makes Lesson’s name a junior homonym of Wagner’s name, and as such it should normally have been replaced with a new name. However, we argue that the name rufus has never been in prevailing usage for the Gray Mouse Lemur and is thus a nomen oblitum, hence the junior homonym should be retained as valid. There is no holotype for Lesson’s Gliscebus rufus , but E. Louis and his team collected a lectotype for what they considered to be the Rufous Mouse Lemur near Ranomafana National Park in 2006 and deposited the live specimen at the Parc Botanique et Zoologique de Tsimbazaza in Antananarivo. J.-J. Petter and colleagues in 1977 noted geographic variation in morphology (especially ear size) in the range of this species, until recently considered to extend throughout the island’s eastern forests from Tolagnaro (= Fort-Dauphin) in the south perhaps as far as the Tsaratanana Massif and just south of the Makira region in the north, and C. P. Groves, in his 2001 book Primate Taxonomy, suggested that northern specimens were darker and shorter-tailed than those from the south. Part of the variation can be accounted for by the identification of new species from within what was thought to be the range of M. rufus . It is believed that there are still as yet unrecognized species that await description. Monotypic.

Distribution. SE Madagascar; its precise limits are not known, but it is believed to occur from the Ranomafana National Park to Andringitra National Park, including the corridor between them.

Descriptive notes. Head-body 12 cm, tail 10.9-12.5 cm; weight 44 g. The Rufous Mouse Lemur is probably the smallest of the eastern rainforest mouse lemurs, and it does not show significant differences in body weight between sexes. It is a slightly built species. Head and forelimbs are reddish-brown, blending into a grayish-brown dorsum and tail. The underside is grayish-white. A black midline stripe runs the length of the back. A conspicuous white rostral patch does not extend past the level of the eyes. Ears are naked and short, being half-hidden in the fur of the head. The tail is relatively long.

Habitat. Tropical moist lowland and montane forest from sea level to 2000 m and occasionally in adjacent secondary forest formations, bamboo forest, old plantations, and Eucalyptus (Myrtaceae) groves.

Food and Feeding. The Rufous Mouse Lemur is omnivorous. During the wet and early-dry season, it mainly eats fruits but also flowers, buds, gums, insects (especially beetles), and occasionally young leaves. During the late-dry and early-wet seasons,it prefers to eat insects (Coleoptera, Orthoptera, Hymenoptera, Heteroptera, Diptera, Lepidoptera, Hemiptera, Siphonoptera, and Ephemeroptera ). Fruits from three species of mistletoe ( Bakerella , Loranthaceae ), an epiphytic semi-parasite genus endemic to Madagascar, seem to be a particularly important dietary component. Mistletoe fruits have a high fat and fiber content and are consumed when other fruit availability is relatively low. Other fruits are consumed from Medinilla (Melastomataceae) , Ficus (Moraceae) , Rhipsalis (Cactaceae) , Viscum ( Santalaceae ), and Psychotria (Rubiaceae) . Flowers are eaten from Weinmannia bojeriana ( Cunoniaceae ) and species of Micronychia (Anacardiaceae) . Rufous Mouse Lemurs are usually seen feeding in shrubs and low trees. Fat storage in the tail seems to be less important than in the Gray Mouse Lemur .

Breeding. Mating takes place in September and October, during which time the male’s testes increase significantly in size. Usually one to three young are born per year, in November or December following a two-month gestation. Captive female Rufous Mouse Lemurs may breed twice annually. Offspring have a gray back and a cream-colored belly, contrasting sharply with the reddish-brown of their mother. Play occurs between the mother and herjuveniles, during which the young will chase their mother and occasionallyjump on hertail or hands. Independence is attained by two months of age.

Activity patterns. The Rufous Mouse Lemur is nocturnal and arboreal. Individuals sleep in tree holes and leaf nests during the day, and they have even been observed using old bird nests. During the austral winter from May through September, most females and some males enter torpor and lose 5-35 g in weight in the process. Males become active again in August, but females remain torpid for one or two more months.

Movements, Home range and Social organization. Ecology and behavior of the Rufous Mouse Lemur have been studied in Ranomafana National Park. Male territories are larger than those of females, and often overlap two or more home ranges of females and other males. Males may move between female home ranges. Home range may be influenced by distribution of high-lipid fruits, which are a preferred food source. The Rufous Mouse Lemur is a solitary forager. Many earlier studies of “ M. rufus ” were actually of some of the newly described taxa; for example,J. Ganzhorn actually studied Goodman’s Mouse Lemur ( M. lehilahytsara ) at Analamazaotra Special Reserve. It can be found at high densities, such as 23-5 ind/km? in Ranomafana National Park.

Status and Conservation. CITES Appendix I. Classified as Least Concern on The [UCN Red List. However, at the IUCN/SSC Lemur Red-Listing Workshop held in July 2012, the Rufous Mouse Lemur was assessed as vulnerable based on new information about the severe fragmentation of its remaining habitat. As with most members of the genus Microcebus , the principal threat to the Rufous Mouse Lemuris habitat loss due to slashand-burn agriculture. Discovery of several undescribed Microcebus species has resulted in a significantly reduced distribution for the Rufous Mouse Lemur . Clarification of the distributions of recently described species is sure to reduce its distribution even further. Its status thus needs to be reassessed in the light of the taxonomic splitting in recent years. It is known to occur in Andringitra and Ranomafana national parks and Pic d’Ivohibe Special Reserve.

Bibliography. Atsalis (1998, 1999a, 1999b, 2000, 2008), Duckworth et al. (1995), Feistner & Schmid (1999), Fleagle (1999), Ganzhorn (1987, 1988), Glatston (1979), Goodman, O'Connor & Langrand (1993), Groves (2001), Harste et al. (1997), Kappeler (1991), Langrand & Goodman (1996), Louis, Coles et al. (2006), Louis, Engberg et al. (2008), Martin (1972, 1973), Mittermeier et al. (2010), Nicoll & Langrand (1989), Petter et al. (1977), Pollock (1979b), Rowe (1996), Tattersall (1982), Wagner (1839), Wright & Porter (2004).

Figures

1. Gray Mouse Lemur (Microcebus murinus), 2. Gray-brown Mouse Lemur (Microcebus griseorufus), 3. Madame Berthe’s Mouse Lemur (Microcebus berthae), 4. Peters’s Mouse Lemur (Microcebus myoxinus), 5. Golden-brown Mouse Lemur (Microcebus ravelobensis), 6. Bongolava Mouse Lemur (Microcebus bongolavensis), 7. Ambarijeby Mouse Lemur (Microcebus danfossi), 8. Margot Marsh’s Mouse Lemur (Mucrocebus margotmarshae), 9. Sambirano Mouse Lemur (Microcebus sambiranensis), 10. Nosy Be Mouse Lemur (Microcebus mamaratra), 11. Tavaratra Mouse Lemur (Microcebus tavaratra), 12. Montagne d’Ambre Mouse Lemur (Microcebus arnholdi), 13. Rufous Mouse Lemur (Mucrocebus rufus), 14. Jolly’s Mouse Lemur (Microcebus jollyae), 15. Gerp’s Mouse Lemur (Microcebus gerpi), 16. Goodman’s Mouse Lemur (Microcebus lehilahytsara), 17. Simmons’s Mouse Lemur (Microcebus simmonsi), 18. Anjiahely Mouse Lemur (Mucrocebus macarthuri), 19. Mittermeier’s Mouse Lemur (Microcebus mittermeieri)

Distribution. SE Madagascar; its precise limits are not known, but it is believed to occur from the Ranomafana National Park to Andringitra National Park, including the corridor between them.