An updated survey of molecular diversity in Madagascar's velvet geckos, genus Blaesodactylus, with description of a new species from the island’s arid West

Abstract

Madagascar velvet geckos, genus Blaesodactylus, are classified in six species distributed over low-elevation sites across most of Madagascar. Based on DNA sequences of one mitochondrial and two nuclear-encoded gene fragments obtained from numerous newly collected tissue samples, we provide an updated review of their molecular variation. Our genetic screening confirms an extended distribution of B. ambonihazo, so far only known from its type locality Ankarafantsika, now reaching northwards to the Sahamalaza Peninsula.

Compared to previously available molecular data, we also verify minor range extensions of B. boivini (southeastwards to Bezavona), B. antongilensis (northwards to the Marojejy Massif), and the B. sakalava complex. Samples assigned to B. sakalava according to current taxonomy fell into two mitochondrial sister lineages differing by about 8.5% pairwise distances in the 16S rRNA gene, lack of haplotype sharing in the nuclear-encoded CMOS gene, and various subtle but consistent differences in body proportions and scalation.

We conclude that the lineage occurring in the South of Madagascar, encompassing known locations south of Morombe, corresponds to B. sakalava sensu stricto based on its type locality and morphological characters of its name-bearing type; and describe the lineage occurring in the West of Madagascar north of Morombe as a new species, B. ganzhorni sp. nov.