Shell medium sized, equivalve, strongly inequilateral. Outline oblong longer than high; length to height ratio depends on the available space; umbo almost terminal; posterior part expanded forming a carina; posterior margin rounded. Ligament external. Weak cancellate sculpture of prominent radial lines crossed by weak concentric growth lines. Diagnostic is the dentition in hinge: rv with two well developed cardinal teeth and three lateral; lv with two cardinal, and two lateral teeth. No pallial sinus. Inner margin smooth.
common size :
to 60 mm in length.
Its clearly radiating sculpture, yet with weak concentric lines, distinguished it from the closely related Coralliophaga coralliophaga (Gmelin, 1791) where the main feature is the thin raised lamellae.
BIOLOGY / ECOLOGY
The Trapeziidae are primarily byssate forms.
nestling in crevices or beneath coral debris and rocks (Oliver, 1992).