Molecular evidence for the monophyly of tenrecidae (mammalia) and the timing of the colonization of Madagascar by Malagasy Tenrecs

Tenrecs are a diverse family of insectivores, with an Afro-Malagasian biogeographic distribution. Three subfamilies (Geogalinae, Oryzorictinae, Tenrecinae) are restricted to Madagascar and one subfamily, the otter shrews (Potamogalinae), occurs on the mainland. Morphological studies have generated conflicting hypotheses according to which both tenrecids and Malagassy tenrecs are either monophyletic or paraphyletic. Competing hypotheses have different implications for the biogeographic history of Tenrecidae. At present, there are no molecular studies that address these hypotheses. The present study provides sequences of a nuclear protein-coding gene (vWF) and the mitochondrial 12S rRNA, tRNA valine, and 16S rRNA genes from a potamogaline (Micropotamogale). New sequences of these genes are also reported for the tenrecine, Tenrec ecaudatus. The 12S sequences from these taxa were combined with data already available for this locus from two other tenrecids (Echinops telfairi, subfamily Tenrecinae and Oryzorictes talpoides, subfamily Oryzorictinae). Phylogenetic analyses provided strong bootstrap support for the monophyly of Tenrecidae and Malagasy tenrecs. The majority of statistical tests rejected morphological claims for both a Tenrecinae--Chrysochloridae clade and an Oryzorictinae--Potamogalinae clade. Molecular clock estimates suggest a split of otter shrews and Malagasy tenrecs at approximately 53 MYA. We estimate that the ancestor of Malagasy tenrecs dispersed to Madagascar subsequent to this split but prior to about 37 MYA.