Shell, equivalve, equilateral rather inflated and thin. Outline circular. Lunule intermediate in length and much more developed in the rv. Sculpture divaricate of skewed rather narrow ribs. Angle of divarication 100-135°C. Four radial sulci on the anterior part. Ligament marginal. Hinge with two cardinal teeth in lv, one cardinal on rv. Lateral teeth obsolete. Inner margin minutely denticulate.
common size :
shell to 20 mm. Maximum in Red Sea 22 x 21 x 7 mm.
The species is differentiated from other Indo-West-Pacific Divalinga by the smaller size, thin shell obscure denticulated inner margin and relatively narrow ribs. D. arabica is most close to the American species D. quadrisulcata but differs from it in the thinner shell, the sharper angle of divarication and especially in the less developed lateral teeth (Dekker and Goud, 1994).
BIOLOGY / ECOLOGY
Infaunal siphonate, actively mobile, unattached animals found 2-3 cm deep buried in sand during low tide near the low water mark. Chemosymbiotic deposit feeders.
in sand (quartz sand not coral sand) in shallow water; also in seagrass beds at depth 1-2 m.