Dosinia Concentrica (Born, 1778) - Southern Dosinia

This species measures up to 7.5 cm long; it is sturdy, inequilateral  (beaks prominent, pointed and anterior to midline), and broadly circular in shape. It has a glossy yellowish-white color and is sculptured with many low, smooth, neat and even, concentric ribs or ridges which become closer together in the umbonal region, and closer together and more prominent in the posterior region. In a specimen about 4.5 cm high there were twelve of these ribs in the first cm, and eleven in the first cm from the ventral margin inwards along the midline. In some old specimens, the ribs had been worn away and the shell was a chalky white or grey color. Growth rings are visible, but there is no axial sculpture and can thus be easily distinguished from the other Veneridas. The inside of the shell is smooth and white. There are three cardinal teeth in each valve, but in the right one the posterior is grooved along its length thus appearing double. The margins are smooth but in the region of the lunule there is a characteristic indentation. The pallial sinus is fairly well developed.