A cryptic and critically endangered species revealed by mitochondrial DNA analyses: the Western Ground Parrot

We examined cytochrome b sequence data to resolve the intraspecific taxonomy of ground parrots Pezoporus wallicus. The species occurs in fragmented coastal heaths in south-eastern and south-western Australia. Net nucleotide divergences among all eastern populations were very low (0.0–0.6%) and genetic diversity unstructured, suggesting relatively recent common ancestry. Gene flow among them was probably maintained via land bridges and the persistence of suitable habitat during the Pleistocene. In contrast, net nucleotide divergence was high (4.4–5.1%) between western and eastern populations, suggesting more ancient divergence about 2 million years ago. The magnitude of divergence between eastern and western lineages is similar to a wide range of avian congeners. Our data support the need to reconsider the intraspecific taxonomy of ground parrots, and we cautiously suggest the recognition of Western Ground Parrots as a species, P. flaviventris, for conservation prioritization, planning and management purposes. Given their recent precipitous decline to approximately 110 individuals, most of which occur at one location, this makes Western Ground Parrots one of the world’s most threatened bird species.