Different coat colour might not correspond to different species for nocturnal lemurs. In a study published today in the open access journal BMC Evolutionary Biology, researchers find that lemurs that appeared to belong to different species because they have strikingly different coat colours, are in fact genetically related and belong to the same species.

Kellie Heckman, from Yale University collaborated with colleagues from other institutions in the USA to sequence a mitochondrial gene called cytochrome b, in 70 mouse lemurs. The lemurs were thought to belong to up to three different species because they live in different forest habitats and have distinctive coat colours.

However, surprisingly, Heckman et al.'s phylogenetic analysis reveals that the 70 lemurs do not differ genetically. According to their cytochrome b sequence, they all belong to the same, previously identified species, Microcebus griseorufus. The authors also show that the three different coat colours observed are found in all three geographical locations in similar proportions. Because they are nocturnal animals, these lemurs tend to depend more on auditory cues or smell to recognise each other, than on visual cues, such as coat colour. This could explain why a certain amount of variation in coat colour does not affect species recognition in mouse lemurs.

The authors of the study recommend caution when identifying new species of lemurs. They conclude that an approach combining morphological, genetic, geographic, and ecological data is the most likely to give an accurate picture of species diversity.