Shell medium sized, solid, equivalve, inequilateral; umbones well in the anterior part of shell. Outline elongate, almost twice longer than high; dorsal margin sloping to a narrowed posterior margin; anterior rounded slightly acute. Hinge without lateral teeth (see detailed photo below). Well defined lunule slightly depressed. Surface shining. Sculpture smooth with growth lines only. Pallial sinus round pointing to the beaks reaching half the shell's height. Internal margin smooth.
Detail of the dentition
photo: S. Xentidis
externally beige, pale yellow with a characteristic zig-zag pattern in brown. Internally white.
common size :
shell to 50 mm.
This species may be confused with P. undulata (Born, 1778); the latter has a characteristic undulated sculpture, oblique to the growth lines; less elevated outline and less inflated valves (Fischer-Piette and Métivier, 1971).
BIOLOGY / ECOLOGY
Filter feeder. Burrows in deep continental shelf waters bottom where it can dominate the molluscan fauna. Its affinities are with warm Indo-Pacific faunas and normal marine salinities (Cooper, 1990).
common on offshore shelf bottoms (Barash and Danin, 1992).