Eared ark

Anadara notabilis

Family Arcidae - arks

Bivalve (2 shells), shell oval, very inflated, "wings" on both sides of beak; color white, may have brown outer skin (periostracum); anterior end short, rounded; posterior end extended with concave indentation on lateral margin; thick radial ribs; fine concentric ridges in between and across radial ribs giving the ribs a beaded appearance; furthest anterior ribs may be grooved down center; hinge long, straight; teeth along length of hinge, largest teeth on posterior end, teeth hug upper hinge edge; interior edges of shell scalloped.
Similar Species
Similar in shape to the cut-ribbed ark, A. floridana, but the cut-ribbed ark has grooves down the center of its ribs. The eared ark only has grooves on the anterior most ribs. Also the teeth in the eared ark closely hug the hinge upper margin through its entire length. In the cut-ribbed ark, the anterior teeth slope away from the upper margin. In the transverse ark, A. transversa, the hinge teeth hug the upper margin of the hinge except at the ends, both posteriorly and anteriorly, where they slope away. Neither the cut-ribbed or transverse ark have the indented posterior margin.
Bay, sand or muddy bottoms, seagrass beds
Maximum Size
5.5 cm (2 1/2 in)
Other Common Names
Previous Scientific Names
Arca auriculata, Arca deshayesi