Blood ark

Lunarca ovalis

Family Arcidae - arks

Bivalve (2 shells); shell round to circular to ovate, inflated, left shell slightly overlaps right shell; color white, has a has a furry, dark brown outer skin (periostracum); strong radial ribs with weak groove in center of ribs; beaks curve anteriorly; beaks close together; internal margins deeply scalloped; hinge line slightly arched; hinge teeth all on posterior side of shell, ends at beak anteriorly; ligament on posterior side very narrow.
Similar Species
The blood ark can have several shapes. The easiest way to distinguish it from other arks is by the hinge teeth. Teeth end anteriorly under the beaks. Also ribs have weak grooves down center.
Gulf and bay, muddy to sandy bottoms
Maximum Size
6.4 cm (2 1/2 in)
Other Common Names
Previous Scientific Names
Anadara ovalis
Named so because, unlike most mollusks, it has red blood.