Morphometrics confirm taxonomic deflation in dwarf lemurs (Primates: Cheirogaleidae), as suggested by genetics

Abstract

Detailed knowledge of the identity and distributions of extant species is essential for unravelling patterns and mechanisms of biodiversity, and it provides indispensable baseline data for conservation efforts. The taxonomy of the primates of Madagascar (Lemuriformes) has experienced drastic revisions in the last decades, with species numbers skyrocketing, especially in the genera Microcebus, Avahi, and Lepilemur. The dwarf lemurs (genus Cheirogaleus) have received less attention in terms of their taxonomy, even though they are closely related and syntopic with these diverse genera. The last revision of the genus was based on morphological data from museum specimens, and accepted seven species: Cheirogaleus medius, Cheirogaleus major, Cheirogaleus crossleyi, Cheirogaleus adipicaudatus, Cheirogaleus sibreei, Cheirogaleus ravus, and Cheirogaleus minusculus, whereas a more recent multilocus molecular study only detected three lineages: C. medius, C. major, and C. crossleyi. The goal of this study was to reassess the currently accepted taxonomy of the genus by examining six external and 32 craniodental characters of 120 museum specimens and 36 new specimens from the field. This study, in conjunction with a complementary molecular study, revealed lower diversity and a lower number of distinct morphs of dwarf lemurs than previously postulated. We conclude that in our sample there are three distinct morphs in the genus Cheirogaleus that correspond to C. medius, C. major, and C. crossleyi. We formally recognize C. adipicaudatus and C. ravus as synonyms of C. medius and C. major, respectively, and consider C. minusculus and C. sibreei to be potential synonyms of C. medius.