The genus Cheirogaleus: Unrecognized biodiversity in dwarf lemurs

Two species of dwarf lemurs (Cheirogaleus) of Madagascar are conventionally recognized. To investigate this taxonomy, I studied the samples in the London and other collections. I could distinguish 7 different morphs, differing by size and by features of pelage, ears (hairy or naked), ear size, tail length, skull shape and dentition. As multiple features differentiate each form, they cannot be simply morphs within the two conventional species: they are discrete genetic entities, hence distinct species. The Cheirogaleus medius species group is split into two closely related allopatric species, C. medius from the western dry forests and C. adipicaudatus from the southern spiny forest. The Cheirogaleus major group has two widespread and partially sympatric species: C. major from the lowland rain forests and C. crossleyi from the plateau margins. I describe a species previously known only from the type series, Cheirogaleus sibreei, and two new species, one sympatric with C. major and one, apparently allopatric to all others, from the central plateau. I also discuss problems of nomenclature, dating from the original description itself.