White Hammer Oyster
The White Hammer Oyster is one of the most unusual types of marine bivalve molluscs and easily recognised by its greatly elongate hinge extensions (recalling a hammer shape) and somewhat corrugated valves. Reaching a shell length of 200 mm, it lives on the surface of sandy-mud substrates in intertidal and shallow subtidal areas (to 5-10 m), often partly encrusted with marine growths. Large specimens are usually loose, but juveniles are anchored by byssal threads to rocks and/or dead shells. Internally the shell valves exhibit a nacreous (pearly) appearance. The closely related species, the Black Hammer Oyster (Malleus malleus) has a much darker shell than the White Hammer Oyster, but sometimes occurs in the same localities.
Indo-West Pacific: Subtropical and tropical Australia.