Atrina serrata (G. B. Sowerby I, 1825) Sawtooth Penshell And Symbionts

     This large (over 310 mm. in length) Sawtooth 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 pair of the Palaemonid Shrimp Pontonia domestica  [Atlantic Pen Shrimp] were found living inside the shell - an example of commensalism. Click on the respective shrimp insets of the image below for higher resolution images of the respective shrimp.

Another Atrina serrata symbiont