Fluted giant clam (Tridacna squamosa) in between coral, Mu Ko Lanta Marine National Park, Thailand

Description

Tridacna squamosa is one of a number of large clam species native to the shallow coral reefs of the South Pacific and Indian Oceans. It is distinguished by the large, leaf-like fluted edges on its shell called ‘scutes’ and a byssal opening that is small compared to those of other members of the Tridacnidae family. Normal coloration of the mantle ranges from browns and purples to greens and yellows arranged in elongated linear or spot-like patterns. Tridacna squamosa grows to 40 centimetres across. Sessile in adulthood, the clam’s mantle tissues act as a habitat for the symbiotic single-celled dinoflagellate algae (zooxanthellae) from which it gets a major portion of its nutrition. By day, the clam spreads out its mantle tissue so that the algae receive the sunlight they need to photosynthesize.