Pearly brooch-shell
Neotrigonia margaritacea, common name the pearly brooch-shell, is a species of saltwater clam, a marine bivalve mollusc in the family Trigoniidae. This species is known from sandy substrates in shallow seas in southeastern and southwestern Australia. This species was the first member of the family to be discovered alive; previous to its discovery, trigoniids were only known from fossils.
The shell of Neotrigonia margaritacea is thick and heavy for its size. The typical width of the adult shell is 40 mm (1.6 in). In the living animal, the interior of the valves is nacreous and tinged pink. This colour can eventually be lost in empty shells, though a metallic lustre does persist.
This clam is capable of opening its shell quite widely; the valves are kept properly aligned and articulated by a series of massive and smaller teeth on the hinge line. The animal does not have siphons. It respires using filibranch gills. The foot is basically L-shaped, large and muscular, with an additional heel-like lobe.
Neotrigonia margaritacea is a suspension feeder which lives in sand. It is able to move about and can use its foot to jump.
