Pearl Oyster Shells of the Pteriidae Family
Two Pearl Oysters of the Pteriidae Family can be found in this website:
Phylogeny: Pearl Oysters of the Pteriidae Family are bivalve mollusks in the order Ostreida. There are three superfamilies in this order: Ostreoidea, Pinnoidea, and Pterioidea. Until fairly recently the superfamily Pterioidea was divided into three families. That superfamily has now been divided into six families, with the Margaritidae Family having been split from the Pteriidae Family. The most visible distinction between these two families is the width of the hinge plate. The Pteriidae Family is fairly small, with no subfamilies, only two genera, and around thirty species. Shells in this family are also commonly called Winged Oysters, Feather Oysters, Mother of Pearl Shells, or Pteriids.
Description: Pteriidae Pearl Oysters have a rounded outline with a long flat hinge line that extends as “wings” on both sides of the hinge. These shells are moderately inflated and inequivalve (both valves are not equal in size and shape), with the lower valve being more inflated and having an opening for the byssus. These shells are thin and fragile. The exterior surface may be smooth or covered with thin overlapping commarginal plates. The interior is nacreous (having an iridescent luster), with a dark band around the margin. Most species have a thick, dark, periostracum. Pearl Oysters are medium to large-sized, with the largest species in the family being 30 cm (11.7 inches) in length.
Habitat and Distribution: Pteriidae Pearl Oysters are found intertidally, attached to rocks and mangrove roots, as well as in deep water attached to gorgonians and black coral branches. They attach by means on their byssus. They are found as deep as 351 m (1,127 feet), with some sources claiming they exceed 500 m (1,605 feet). Pteriidae Pearl Oysters are found worldwide in subtropical and tropical seas. Three species from this family are found in Mexican waters.
Natural History: Pteriidae Pearl Oysters are suspension feeders, filtering plankton and fine detritus from the surrounding water. In turn they are preyed upon by crabs, predatory mollusks and sea stars. They may be gonochoric or protandric hermaphrodites. They reproduce sexually through broadcast spawning, with external fertilization. These shells have been harvested extensively for their pearls and their nacreous shells, which were historically used for making buttons. They continue to be harvested and cultured for pearl production.