Ophicardelus (Mollusca, Pulmonata) in eastern Australia: how many taxa?

Abstract

The common south-eastern Australian estuarine ellobiid snails belonging to Ophicardelus have been considered to be one variable taxon by some authors, and three largely sympatric species by others. This study was undertaken to determine the number of taxa present. Different types of data collected included shell shape, allozyme electrophoresis, shell and radular morphology, anatomy and geographic range. These data sets were then examined for consistent discontinuities, and the results showed that the nominal species could be distinguished by a combination of shell shape and sculpture. Individuals from each nominal species also grouped together using allozyme data, although one taxon (Ophicardelus quoyi) is sometimes paraphyletic based on these data. There are several differences in the anatomy and radular morphology that separate the three taxa. These included marked differences in the penial complex, vagina, and presence or absence of a pallial gland. The three taxa also have different geographic ranges, albeit with most of their ranges in sympatry. Based on these differences, Ophicardelus ornatus, O. quoyi and O. sulcatus should be regarded as valid species.