Lemurs! The Evil Greg Laden Beat Me To The Lemurs

Greg scooped me on the lemur research but that’s okay because I beat him to the gorilla sex story. So, what is the story about?

A paper recently published in Genome Research looks at the phylogeny of the Lemuriformes. The study includes DNA from 29 species of the Lemuriformes and includes 11 loci from nine chrommosomes (as well as 7 loci previously published loci) covering approximately 9 kb of nuclear sequence data. Additional data was included from previously existing data banks. Based on the data the authors were able to construct a phylogeny of the Lemuriformes and estimate divergence times. The results tended to confirm previous analyses with one twist, which I will get to in a moment. Horvath et al summarize current thinking:

Despite these weaknesses, virtually all phylogenetic studies of lemurs and related primates agree on three points: (1) lemurs are monophyletic; (2) the lemuriform clade is most closely related to the African and Asian lorisiform clade, together forming the tooth-combed primate clade strepsirrhini; and (3) the strepsirrhine clade is sister to all other living primates. Moreover, the majority of these studies have found that the ayeaye, genus Daubentonia (family Daubentoniidae), is sister to a clade composed of all other lemurs, including the recently extinct giant lemurs (Karanth et al. 2005). Beyond this result, however, there has been complete disagreement among studies as to the relationships among the other four major evolutionary lineages, also classified as families. Virtually every conceivable phylogenetic resolution has been presented among the Cheirogaleidae, Indriidae, Lemuridae, and Lepilemuridae (containing the single genus Lepilemur) in studies where taxon sampling has been adequate to investigate their relationships. [bold mine – afarensis]

The bolded part is the twist I mentioned above, because Horvath et al’s data allows them to resolve the issue:

Here the Aye-aye is the sister clade to all the other lemurs. The Cheirogalidae (dwarf and mouse lemurs) and the Lepilemuridae (sportive lemurs) form a sister clade, which in turn is a sister clade to the Indriidae (sifakas). The Eulemurs (brown lemur and related species) form a sister clade with the bamboo lemurs and ring-tails (and related species) and this group is the sister clade to the genus Varecia (the ruffed lemurs). The Eulemur/Hapalemur/Lemur/Varecia group form a sister clade with the Cheirogalidae/Lepilemuridae/Indriidae clade.
Divergence time estimates range from 66.22 (54.91-74.74) MYA for the Daubentonia/Lemur split to 970,000 (420,000-1.6 MYA) for the red ruffed lemur/black and white lemur split. Equally interesting was the section relating divergence times to the biogeographical context, but you will have to read that for yourselves.