Southern Quahog
Mercenaria campechiensis (Gmelin, 1791)
Family Veneridae
The Southern Quahog is a large thick ridged clam up to 7" which is common on the S. Hutchinson Island beaches. Dispite its size it can be quite beautiful.
Several Southern Quahogs (S. Hutcxhinson Island- December 2020)
Harry Lee: "The persistence of the commarginal (concentric) ribs over the outer shell is the most salient shell characteristic n the distinction from the Northern Quahog."
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Shell size to 150 mm; shell thick, more inflated than in Mercenaria mercenaria, ovate-trigonal. Sculpture of irregular lines, more separated than in M. mercenaria. Lines never absent in middle of valve. Lunule as long as wide. Color dull-white to gray. Internally sometimes stained with purple. This species hybridizes with M. mercenaria in the southeastern United States. Juvenile shells (additional photo, size 30 mm) have purple zigzag lines; do not confuse these with Chione elevata or Chionopsis intapurpurea.