Molecular systematics and historical biogeography of the rock-thrushes (Muscicapidae: Monticola)

The genus Moilticola consists of 13 putative species with distributions throughout Eurasia and the sub-Saharan region of Africa. As such, this genus provides an excellent model with which to explore historical intercontinental movements and forces driving speciation in southern Africa. To address these questions, we reconstructed a hypothesis of species relationships using the mitochondrial ND2 and cytochrome-b genes. Monticola forms a well-supported, monophyletic clade within the avian family Muscicapidae. Our results support previous studies suggesting that the Malagasy genus Pseudocossyphus be subsumed into Moaticola, and suggest that several of the Malagasy species (notably M. bensoni and M. erythronotus) are not valid. Sequence data, along with morphological and distributional evidence, support the elevation of M. pretoriae to species status. Historical biogeographic analyses suggest an area of origin for Monticola in the arid region of northern Africa plus Saudi Peninsula or the African savanna, or both. Determination of speciation timing suggests that Monticola arose similar to 5.5 mya, with subsequent lineage splits occurring throughout the Pliocene and Pleistocene. We propose that climate-driven ecological vicariance as well as dispersal were important in the biogeographic history of this group and are responsible for present-day species relationships and distributions.