Shells are ovate, slightly inequilateral, and strongly convex. Sculpture consists of fine concentric ribs. Valves are strongly inequivalve (one valve larger than other).
Size: 5-10 mm.
Ecology: inhabits shallow-offshore marine (10-100 m) waters, burrowing in silt near the sediment surface.
Geological range: Late Miocene-Late Pliocene (11-3 million years ago).
Geographic distribution: Caribbean – Panama and Costa Rica.
