Related FAQs:  Bivalves, Bivalves 2, & Bivalve Identification, Bivalve Behavior, Bivalve Compatibility, Bivalve Selection, Bivalve Systems, Bivalve Feeding, Bivalve Disease, Bivalve Reproduction, Tridacnids, Tridacnid Clam Business,  Tridacnid Identification, Tridacnid Selection, Tridacnid Compatibility, Tridacnid Systems, Tridacnid Lighting, Tridacnid Placement, Tridacnid Feeding, Tridacnid Disease, Tridacnid Reproduction, Flame Scallops, Related Articles: Mollusks, Giant Clams/Tridacnids,  /The Conscientious Marine Aquarist Bivalves: Clams, Oysters, Mussels... Class Bivalvia, Pt. 3  To: Pt. 1, Pt. 2,

By Bob Fenner

Family Pinnidae: Penshells

Atrina rigida, the Stiff Penshell. Found singly in sand, rock or sponges. Light to dark brown raised-ridge shells. Tropical west Atlantic. Roatan 2019.

Pinna carnea, the Amber Penshell. Found singly in mud, sand, interspersed between rocks on reefs, fore-reefs. Look like their thin shells were stuck in the sand facing up, slightly agape. Tropical west Atlantic. Bonaire pic of a view from above.

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Pinna rugosa, the  Penshell. Found singly in mud, sand, interspersed between rocks on reefs, fore-reefs. Look like their thin shells were stuck in the sand facing up, slightly agape. E. Pacific, Baja to Peru. Costa Rica (Pacific side) 2011

Family Pectinidae:

Pedum spongyloideum (Gmelin 1791), the Iridescent Scallop. Red Sea, Indo-Pacific. Live embedded in various corals, usually Porites spp. Grow to a couple of inches across. Not boring organisms, but preclude growth where they attach. Gili, Lombok, Indo. and Red Sea pix.

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Thorny Oysters, Family Spondylidae: Have sturdy, ribbed shells, sometimes with continuing projections at their openings. Attached to rocks. When open have colorful mantles and small bluish eyes. Four Hawaiian species. 

Spondylus americanus Herman 1781, the Atlantic Thorny Oyster. Caribbean. Deep red, rounded shell to six inches across. Here off St. Lucia.

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Spondylus calcifer, Spiny Oyster. Mantle is black/white banded with yellow streaking. To half a foot in diameter. Found attached on rocky reefs to 75 feet depths. Sea of Cortez to Ecuador. Cabo 2016

Spondylus linguaefelis Sowerby 1847, Carl's Tongue Thorny Oyster. Long thin spines that reminded the namer of a "cat's tongue" in their roughness. This is a tentative ID... This animal photographed in S. Sulawesi. Range given for this species as Hawai'i and Clipperton Islands.

Spondylus varians Sowerby 1829, the Variable Thorny Oyster. The most common bivalve in its Western Pacific range. Orange mantle, blue eyes, white spines (typically overgrown) on overall shell. This one off the Gilis, Lombok and N. Sulawesi, Indonesia.

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Spondylus violacescens Lamarck 1819, the Cliff Oyster. As the common name suggests, this bivalve is found on the undersides and clefts of rocks. To four inches in diameter. Empty attached shell often with white middle, purple or orangish ring on inside perimeter. Big Island, Hawai'i pix. Here attached under rocks.

Bigger PIX:  Spondylus sp. Red Sea 08 The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

To: Pt. 1, Pt. 2,