Batillaria australis (Quoy and Gaimard, 1833)

Distribution: 

Abundant in coastal estuary and mangrove regions of the Solitary Islands Marine Park. Endemic to Australia, on the east coast from the Whitsunday Islands in Queensland through to Victoria and Tasmania.

Ecological Notes: 

Found in mangrove and estuary habitat, favouring the tidal flats above mid water. Forages in the mud for detritus, often leaving telltale trail.

Additional Notes: 

Exterior colour brown, sometimes with a white spiral band, columella fawn, interior of outer lip purplish brown with black lirae, operculum circular, corneous. Shell sculptured with nodular ridges around the whorls and raised folds running obliquely across them. Studies indicate breeding of this mollusc species takes place in the summer with most snails breeding at the end of their second year. Life span was found to be around four years in total. Similar in shape to Pyrazus ebeninus which lives in similar habitat but is somewhat larger. This species is one of the hosts for the flatworm parasite Austrobilharzia, the larvae of which are discharged into surrounding waters. They then burrow into the legs of wading birds, and may burrow into the skin of humans causing "bathers itch". The larvae completes its life cycle in birds and cannot survive in a human host. Grows to 49 mm but usually smaller at 30 mm.

References: 

Graham J. Edgar. Australian Marine Life, 2nd Edition, 2008. Reed New Holland Publishers. p.289.

The Seashells of New South Wales, Des Beechey, Senior Fellow, Australian Museum, Release 25. Website at https://seashellsofnsw.org.au/Batillariidae/Pages/Batillaria_australis.htm. Accessed 16/10/2018.