Lemur Phylogeny and Evolution

The Malagasy lemurs comprise more than 35 species, all unique to Madagascar. These primates display an extraordinary array of morphologies, behaviors and lifestyles, thus making them a fascinating group for study in a variety of scientific fields.

In the 1970's, several papers were published that questioned the phylogenetic unity of the Malagasy primate lineage. These papers were primarily concerned with the phylogenetic position of the mouse and dwarf lemur group (family Cheirogaleidae) relative to the Afro-Asian galagos and lorises (infraorder Lorisiformes), concluding that the two groups form a clade that excludes the remaining Malagasy primates.

The phylogenetic position of the aye-aye (Daubentonia madagascariensis) has also been considered problematic. Its bizarre morphology and unusual ecological specializations have made phylogenetic placement within the Strepsirrhini difficult. The phylogenetic confusion has therefore made it difficult to arrive at a realistic biogeographic model to explain the presence of primates on Madagascar.

In an effort to resolve these phylogenetic and biogeographic issues, I have spent much of my career analyzing both the morphology and select regions of the genome for a large sample of strepsirrhine taxa. These studies have yielded a robust phylogenetic hypothesis that, in addition to its agreement with other molecular phylogenetic studies, provides an elegant model of lemur origins.

Analyses have demonstrated that the diverse primate fauna of Madagascar is monophyletic and thus the product of a single colonization of an ancestral primate that arrived from Africa, probably during the early Eocene (Yoder et al. 1996, PNAS).

We are currently developing new genetic markers to further investigate the sequence and timing of major events in lemuriform evolution. We are also interested in clarifying taxonomic diversity within the Lemuriformes, particularly at the species level.