Distinct taxonomic position of the Madagascar stonechat (Saxicola torquatus sibilla) revealed by nucleotide sequences of mitochondrial DNA

Stonechats (genus Saxicola) are passerine birds with an extraordinarily large breeding distribution. Recent studies provide strong evidence that the taxon shows far greater geographic differentiation than originally suspected, with African, Siberian and European stonechats forming distinct, monophyletic groups that have been suggested to be species in their own right. Here, we present additional data on the geographic differentiation among African stonechats, Saxicola torquatus. Nucleotide sequences of the mitochondrial NADH dehydrogenase subunit 2 and cytochrome b genes indicate that the stonechats from Eastern Madagascar (Saxicola t. sibilla) form a distinct clade and that they constitute a monophyletic group with stonechats from mainland eastern Africa (Saxicola t. axillaris) and La Réunion (Saxicola tectes). The genetic and morphological data suggest that the Madagascar stonechat is very likely to be a distinct species, Saxicola sibilla (Linnaeus 1766). However, further studies are needed to verify this. A detailed description of the plumage and various external body measurements is given.