The ecology and distribution of Halicarcinus lacustris (Brachyura: Hymeno-somatidae) in Australian inland waters

Abstract

Halicarcinus lacustris is a small crab inhabiting inland waters in south-eastern Australia, New Zealand, and Lord Howe and Norfolk Islands. The Victorian distribution was investigated with reference to salinity. In the field the species occurs over a salinity range of 0.1-9.6‰ (although scarce in fresh waters), despite a tolerance of 0.0-36.3‰ shown by adults in the laboratory. This restricted distribution is attributed to physiological and ecological factors. Ecological notes are included on microhabitat, associated species, food, and the breeding cycle. Consideration is given also to the origins and overall distribution of the species. It is suggested that H. Lacustris rafted across the Tasman Sea, after having evolved in south-eastern Australia.