There are two common
species locally, free-living T. squamosa, and the rock-boring T.
crocea. These bivalves can grow to large sizes (width up to 90cm)
on coral reefs, usually in clear waters.
The mantle (soft tissue) within the shell is brightly coloured brown,
blue and/or green. This is due to the microscopic algae known as zooxanthellae
living inside the tissues which photosynthesise (manufacture food) from
sunlight and the waste metabolic products of the clam. They are then "harvested"
by the clam as supplementary food. Despite being "farmed" this way, the
algae are assured of a safe "residence" and a continued supply of nutrients.
The clam is beginning to grow in importance as a food organism, and ongoing
attempts are being made to cultivate it.