A Morphological and Electrophoretic Examination of Hydrobia Buccinoides, a Variable Brackish-Water Gastropod From Temperate Australia (Mollusca, Hydrobiidae)

Abstract

The morphology of the abundant brackish-water hydrobiid snail known as 'Hydrobia buccinoides' is described. A new genus, Ascorhis, is provided for it and the valid species name for the southern (South Australia, Victoria, Tasmania) and eastern (New South Wales, Queensland) populations is shown to be victoriae T. Woods. The species name buccinoides is based on Assiminea tasmanica and is an earlier name for that species. Morphological and allozyme differences indicate that the Western Australian populations should be distinguished as a separate species and a new name (A. occidua) is provided for these. Both species show a considerable intrapopulation variation in shell sculpture. Salinity tolerance experiments on three Sydney populations indicate that Ascorhis victoriae tolerates a wide range of salinities, the middle of the preferred range being about that of normal seawater.