Distinguishing Characteristics |
Bivalve (2 shells); shell ovoid, slightly triangular in shape, anterior end bluntly rounded, posterior end more angular; beaks large, separated (not touching) when view from the side, hinge line (edges between beaks) straight on top, slightly curved below; ligature area beneath beak (externally) triangular shaped; shell color white, brown furry covering (periostracum) when alive; heavily beaded radiating ribs on left valve, right valve has smooth radiating ribs, beaded only on anterior and posterior ends; beads somewhat elongate (wider than tall); smooth radiating ribs on internal surface; edges of shell crenate (scalloped); left valve overlaps right valve; comb-like teeth on interior of hinge line, teeth becoming smaller towards the center; ventral edge of left shell curved slightly outward when viewed from the ventral side. |
Similar Species |
The incongruous ark is most similar to the triangular ark. The triangular ark has beads that are not as oblong (except possibly on sides) and the shell has a straight ventral anterior edge. |
Habitat |
Gulf and bay, sandy bottoms |
Maximum Size |
6.2 cm (2 1/2 in) |
Other Common Names |
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Previous Scientific Names |
Anadara brasiliana |
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