Phylogeny of the Lemuridae: Effects of Character and Taxon Sampling on Resolution of Species Relationships within Eulemur

Abstract

DNA sequences from three mitochondrial genes and one nuclear gene were analyzed to determine the phylogeny of the Malagasy primate family Lemuridae. Whether analyzed separately or in combination, the data consistently indicate that Eulemur species comprise a clade that is sister to a Lemur catta plus Hapalemur clade. The genus Varecia is basal to both. Resolution of cladogenic events within Eulemur was found to be extremely problematic with a total of six alternative arrangements offered by various data sets and weighting regimes. We attempt to determine the best arrangement of Eulemur taxa through a variety of character and taxon sampling strategies. Because our study includes all but one Eulemur species, increased taxon sampling is probably not an option for enhancing phylogenetic accuracy. We find, however, that the combined genetic data set is more robust to changes in taxon sample than are any of the individual data sets, suggesting that increased character sampling stabilizes phylogenetic resolution. Nonetheless, due to the difficult nature of the problem, we may have to accept certain aspects of Eulemur interrelationships as uncertain.