Biologists from Madagascar and Germany led by Dr Andreas Hapke of the Johannes Gutenberg University’s Institute of Anthropology have described a new, extremely rare species of dwarf lemur that inhabits three isolated forests in the extreme south of Madagascar.

“Together with Malagasy scientists, we have been studying the diversity of lemurs for several years now,” Dr Hapke said.

“It is only now that we were able to determine that some of the animals examined represent a previously unknown species.”

The new species is named Cheirogaleus lavasoensis after the Lavasoa Mountains, which harbor the entire known range of the species. Dr Hapke with co-authors Dr Dana Thiele, also from the Johannes Gutenberg University, and Dr Emilienne Razafimahatratra from the University of Antananarivo, gave it the common name Lavasoa Dwarf Lemur.

The scientists have captured five adult males, five females, and six immature individuals of the Lavasoa Dwarf Lemur during the period from October 2001 to December 2006. They trapped specimens with banana-baited traps. After having anesthetized them, the scientists took small tissue samples from the ear and stored them in tissue buffer at ambient temperature. They also measured the animals and released them at the respective sites of capture at dusk during the same day.

The animals were initially confused with an already described species – the Crossley’s dwarf lemur, also known as the furry-eared dwarf lemur (Cheirogaleus crossleyi). But the new genetic analysis reported in the journal Molecular Phylogenetics and Evolution shows that the specimens are a distinct species.

The Lavasoa Dwarf Lemur measures up to 20 – 22 inches (50 – 55 cm) and weighs up to 0.3 kg. It differs from the Crossley’s dwarf lemur by its shorter head and wider ears.

“The eyes of Cheirogaleus lavasoensis are surrounded by sharply delineated, 3-4 mm wide black eye rings with black hair and darkly pigmented skin, which is broadly continuous with the darkly pigmented, pointed nose. The black hair of the eye ring extends sparsely onto the side of the nose. Crown and forehead are intensely reddish-brown. This coloration extends into a narrow stripe of fur between the eyes, which turns to light grey-brown towards the naked, darkly pigmented rhinarium. Some individuals display small, vaguely defined, light grey-brown patches above the eyes. The ears are darkly pigmented and covered with black hair on the inner and outer side,” Dr Hapke and colleagues described the animal.

“The dorsal neck is reddish-brown. The dorsal and lateral fur on the trunk changes gradually from reddish-brown in the cranial portion to grey-brown in the caudal portion. The lateral coloration of arms and legs is continuous with the adjacent lateral trunk. The dorsal fur on hands and feet is grey-brown in most and reddish-brown in some individuals. The tail is completely grey-brown.”

The Lavasoa Dwarf Lemur is extremely endangered.

“Census data of Cheirogaleus lavasoensis are unavailable,” the scientists wrote.

“Our preliminary estimate is that less than 50 individuals remain.”

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Bibliographic information: Dana Thiele et al. Discrepant partitioning of genetic diversity in mouse lemurs and dwarf lemurs – biological reality or taxonomic bias? Molecular Phylogenetics and Evolution, published online July 27, 2013; doi: 10.1016/j.ympev.2013.07.019