Atrina rigida (John Lightfoot, 1786) Stiff Penshell And Symbiont

     This Stiff Penshell was collected from muddy sand during a minus tide at Vilano Beach, St. Johns County, Florida on 4/16/2007. Upon further investigation a single Pinnotheres maculatus Say, 1818 [Mussel Crab], apparently a symbiont, was found to be in residence. The penshell measures 156 mm. and the crab measures about 12 mm. Click on the crab inset ( top right) of the image below for a higher resolution/and additional image of the crab.

Atrina rigida (John Lightfoot, 1786) Stiff Penshell And Symbiont