Revision of the Lygodactylus tolampyae complex, with descriptions of three additional new dwarf gecko species from Madagascar’s North West

Abstract

The Lygodactylus tolampyae complex currently contains four nominal species of dwarf geckos from the North West and West of Madagascar. These four species are genetically distinct but have been flagged as morphologically cryptic, with only very subtle differences in scale counts between them. Based on new collections and extended molecular datasets, we here investigate the genetic and morphological differentiation of this species complex.

We find seven deeply divergent mitochondrial lineages separated by 9.7–18.0% uncorrected pairwise distance in the 16S rRNA gene which correspond to the four recognized species and three further candidate species. Not a single instance of haplotype sharing between any of these lineages was found in four nuclear-encoded gene fragments, despite several of these lineages occurring in close geographic proximity or even syntopy.

A Principal Component Analysis of morphometric measurements and meristic characters confirmed a wide overlap of most species in morphospace, but the new data also confirm statistically significant differences between numerous lineages in scale counts and morphometric ratios. We conclude that the three candidate species previously known only from very limited material and named Lygodactylus sp. 25, L. sp. 28 and L. sp. 29 correspond to distinct species which we formally name as L. andavambato sp. nov., L. anjajavy sp. nov., and L. arnei sp. nov.

One of the new species, L. andavambato sp. nov. from the limestone karst of the Tsingy de Namoroka, has a peculiar phenotype with slender body and legs, and regular dark crossbands on the tail, differing from all other species in the L. tolampyae complex while superficially reminding L. rarus, a species from the limestone karst massif of Ankarana but belonging to another species group in Lygodactylus. The taxonomic progress, in only a few years, from a single species L. tolampyae to now seven species in this complex calls for further revisionary work, including more fieldwork to survey forest fragments and rocky outcrops across Madagascar which may host yet unknown locally endemic species of dwarf geckos.