Most previous authors placed the sportive lemurs of the genus Lepilemur in the separate family Lepilemuridae. Groves (2001) placed Lepilemur together with the extinct giant lemur, genus Megaladapis, in the Megaladapidae but, based on recent genetic analyses (Yoder et al., 1999b; Karanth et al., 2005), other experts have decided that the relationship between these two lineages is not as close as Groves indicated, and have gone back to separating out the Lepilemuridae. We prefer this arrangement, and return to recognizing Lepilemuridae as separate from the Megaladapidae, and containing a single genus, Lepilemur.
Lepilemur I. Geoffroy, 1851 Sportive Lemurs
The genus Lepilemur contains at least 26 named species, most of which have been described in the past ten years. All are medium-sized, largely folivorous, and nocturnal. Sportive lemurs generally weigh less than one kilogram and are approximately half a meter in length, including the tail. They are vertical clingers and leapers, with legs that are elongated compared to their trunks and arms. The face of Lepilemur is covered with short hairs. Its identification in the field would most likely be confused with the genus Avahi, another medium-sized, nocturnal lemur, but sportive lemurs tend to be a bit smaller, have more prominent ears, and lack the highly visible white patches on the back of the thighs that are so typical of Avahi. Avahi also has a strong tendency to huddle tightly with family members in clusters of two to four animals, sometimes even during the night when they are active. Lepilemur will do this in its daytime sleeping sites, but rarely at night, making this behavior a reasonably good field characteristic. At first glance, or in poor viewing conditions, Lepilemur may also be confused with the larger dwarf lemurs, especially Cheirogaleus major and Cheirogaleus crossleyi in Madagascar’s eastern rain forests. However, Lepilemur is a vertical clinger and leaper, whereas Cheirogaleus moves quadrupedally, and Cheirogaleus species usually have a contrasting white belly. Sportive lemurs can also be readily differentiated from most other nocturnal lemur species by their loud screams, except for Phaner which vocalizes even more loudly. However, this field character is useful only at certain times of the year, when these animals are vocally active.
Sportive lemurs are the smallest of the folivorous primates (Ganzhorn, 1993). Leaves constitute the bulk of the diet, with flowers, buds, and sometimes fruit taking on greater importance toward the end of the dry season. Most populations appear to inhabit low- and mid-altitude evergreen and deciduous forests. Most of what is known about Lepilemur ecology and behavior comes from studies of western and southern species. During the day, sportive lemurs routinely take shelter and sleep in tree holes or tangles of branches, vines, or lianas, and sometimes can be seen resting in the fork of a tree if such shelters are not available. Lepilemur ruficaudatus and Lepilemur edwardsi live in pairs (Ganzhorn and Kappeler, 1996; Thalmann, 2001; Zinner et al., 2003). The social behavior of the other Lepilemur remains unclear and may vary between species. Significant differences in vocal behavior are very apparent, with rain forest species being relatively silent (Petter et al., 1977) while those from more open, drier forests are more vociferous.
The taxonomy of Lepilemur has been fairly complicated over the past 50 years, and continues to be interesting. Petter and Petter-Rousseaux (1960) recognized a single species, Lepilemur mustelinus, with five subspecies, but Petter et al. (1977) increased this to seven species, with one (Lepilemur septentrionalis) having four subspecies. Tattersall (1982) provisionally recognized a single species (L. mustelinus) with six subspecies, but later concurred with Jenkins (1987) that the genus was represented by seven distinct species. This arrangement was supported by at least one genetic analysis (Ishak et al., 1992) and was accepted by most authors in the 1990s (e.g., Mittermeier et al., 1994).
Rumpler et al. (2001), investigating the cytogenetics of L. septentrionalis, identified karyotypes attributable to two species—L. septentrionalis and L. andrafiamensis—each with two subspecies and with no evidence of hybridization between populations. Groves (2001), in contrast, regarded this assemblage as two subspecies of L. septentrionalis—L. s. septentrionalis to the north and L. s. ankaranensis from the forests of Ankarana and Andrafiamena to the south and west—and suggested that the name ankaranensis has priority over Rumpler’s andrafiamensis. Subsequently, Ravoarimanana et al. (2004) and Rumpler (2004) presented data regarding the geographic range of these taxa, elevating these two forms to species and suggesting that the range of L. septentrionalis was restricted to the forests of Sahafary, a very tiny area in the far eastern part of the range of northern Lepilemur.
In the previous edition of this field guide (2006) we recognized eight full species. Since that time a number of scientific papers have been published, and the taxonomy of the genus has been extensively revised, resulting in an explosion of new species. In 2006, Louis et al. described an incredible 11 new species in a single paper—Lepilemur fleuretae, Lepilemur seali, Lepilemur betsileo, Lepilemur wrightae, Lepilemur jamesorum, Lepilemur ahmansonorum, Lepilemur hubbardorum, Lepilemur petteri, Lepilemur grewcockorum, Lepilemur tymerlachsonorum, and Lepilemur milanoii. That same year, Andriaholinirina et al., described a further three species (Lepilemur. aeeclis, Lepilemur randrianasoloi and Lepilemur sahamalazensis), and Rabarivola et al. described Lepilemur mittermeieri. In 2007, Craul et al. described two more new species (Lepilemur otto and Lepilemur manasamody), in 2008, Lei et al. described Lepilemur scottorum, and most recently, in 2009, Ramaromilanto et al. described Lepilemur. hollandorum. Lepilemur manasomody has since been synonymized with L. grewcockorum (Zinner et al., 2007). There is also some dispute over the precise taxonomy of the forms from the region of Nosy Be and the nearby mainland, which has not yet been resolved. However, the net result has been a tripling of species in this genus since the publication of the last edition of this field guide in 2006. We now recognize 26 species, and anticipate that more may be described in the years to come.