Molecular phylogeny of blindsnakes (Ramphotyphlops) from western Australia and resurrection of Ramphotyphlops bicolor (Peters, 1857)

Abstract

Blindsnakes (Typhlopidae) represent one of the least known elements of the Australian herpetofauna. Mitochondrial DNA sequence data and morphology are used here to show that a widespread species of Australian blindsnake, Ramphotyphlops australis, comprises two distinct species. Ramphotyphlops bicolor (new combination) is resurrected from synonymy with R. australis and redescriptions are provided for both species. Mitochondrial DNA sequence variation within R. australis indicates that the central and south-coast populations are more closely related to each other than either is to the morphologically distinctive populations at the northern edge of the species' range. Observed levels of differentiation suggest historical isolation of populations from the Kalbarri/Shark Bay region of the western Australian coastline. However, lack of concordance between mitochondrial haplotype phylogeny and morphology for several individuals might reflect limited gene flow between the northern and south–central populations. We note that many taxa show restricted distributions or range disjunctions along the central Western Australian coastal margin, and we discuss possible models to explain population fragmentation in this region. Pliocene–Pleistocene sea-level fluctuations along the western Australian coast could have isolated sand plain communities in the Kalbarri/Shark Bay region from similar communities further south near Geraldton, possibly underlying the phylogeographic pattern in R. australis. Data from additional taxa will be needed to fully evaluate this hypothesis.