Genetic structure of the western pygmy possum, Cercartetus concinnus Gould (Marsupialia: Burramyidae) based on mitochondrial DNA

Cercartetus concinnus Gould (Marsupialia: Burramyidae) has a spatially disjunct distribution, with a broad stretch of saltbush on the Nullarbor Plain forming an apparent barrier between the population: one in southern Western Australia, and another in south-eastern Australia, encompassing South Australia, Victoria, and New South Wales. This disjunct distribution and slight differences in morphology between western and eastern populations have led to conjecture about the taxonomy of this species. This study assessed the taxonomic status of C. concinnus across southern Australia. Analyses using the mitochondrial (mtDNA) ND4 gene showed little phylogeographic structure throughout the wide range of C. concinnus in southern Australia; closely related haplotypes (~0.1% sequence divergence) had a wide distribution from Western Australia to South Australia, suggesting recent genetic connectivity. These data indicate that C. concinnus populations represent a single taxonomic unit (Evolutionarily Significant Unit) throughout the geographic range. Further research is required to assess the impact of recent population fragmentation and whether an erosion of genetic variation in isolated populations has occurred.