Genetic assessment of the variation and distribution of the species of (Panpulmonata: Amphibolidae) in south-eastern Australia.

Amphibolidae is one of the most abundant families of gastropods in estuarine environments of south-eastern Australia. However, the range limits of the species of , one of the family's two genera in the region, remain unclear partly due to uncertainty of identifications based solely on shell morphology. Insufficient data have been collected to address questions regarding the genetic variability of any of the species of . Here, DNA sequences from a segment of the cytochrome oxidase subunit I and 28S ribosomal RNA genes were collected to investigate the distribution and variation of the three species in the region, these being , and . The results demonstrate a large range extension in and suggest that may have limited distribution in Tasmania. In contrast to previously-studied estuarine Mollusca in the south-eastern coasts of the mainland and Tasmania, has regional differentiation. There is evidence of genetic disequilibrium within , suggesting that it may presently comprise contributions from two distinct sets of populations.