has an oval-shaped shell of two valves (halves) that are of the same shape and size and up to 2 cm in length and 1.2 cm in height. The valves are asymmetrical with the tip of the valves (beak) positioned behind the dorso-ventral mid-line and pointing inwards towards the valves and to the posterior. The shell is brittle to the touch and the surface bears microscopic concentric lines. The external shell surface is a glossy, pearly white, sometimes translucent and is scattered with minute flecks. The interior surface of the hinge is marked with a spoon-shaped pit (chondrophore) near the beak. An indentation is present towards the posterior of the inner hinge as well as adductor muscle scars that are longer and thinner in the anterior region than in the posterior region. The interior of each valve is glossy and translucent in appearance. The right valve bears 2 small, teeth projecting from the hinge and 2 more teeth that are either side of the hinge whereas the left valve bears 1 tooth from the hinge and 2 weaker teeth, again either side of the hinge. The body is simple, bearing a wedge-shaped foot and two very long siphons.Abra nitida
is similar to both Abra alba
, that is larger and less elongate, and Abra prismatica
, that is not quite as oval. Abra nitida
mainly feeds on detritus.