Moon clam vies for Mollusc of the Year, thanks to CU researcher.
A bizarre, perpetually-open clam from Australia is running for Mollusc of the Year, offering scientists a chance to study how unusual animal forms evolve. (University of Colorado Boulder)
Most clams have two-part shells that open and close to protect their soft tissues from predators and the environment. Unlike a typical clam, the moon clams' shells remain apart at nearly 180°, forming a moon-like shape. "I wasn't sure how these animals survive in the ocean, which is a very dangerous place with tons of predators," Li said. "It turns out they live in houses built by other animals." Smaller than a fingernail, moon clams live tucked inside burrows and cracks built by shrimp and sea sponges. They hide in these shelters, feeding on plankton that drifts by. Maintaining a thick hard shell takes a lot of energy, Li said. She suspects that by relying on such a symbiotic relationship with shrimp and sponges, moon clams no longer need to invest as much in building their shells. Instead, the clam seems to have redirected that energy to a different task: sensing the world. Their mantle, the soft flesh that typically lines a clam's shell, extends outward and folds over the shell surface. There are small bumps and tentacle-like structures all over the mantle, and Li said these may act as sensory organs, helping the animal detect changes in its environment through touch or chemical signals.
Most clams have two-part shells that open and close to protect their soft tissues from predators and the environment. Unlike a typical clam, the moon clams' shells remain apart at nearly 180°, forming a moon-like shape. "I wasn't sure how these animals survive in the ocean, which is a very dangerous place with tons of predators," Li said. "It turns out they live in houses built by other animals." Smaller than a fingernail, moon clams live tucked inside burrows and cracks built by shrimp and sea sponges. They hide in these shelters, feeding on plankton that drifts by. Maintaining a thick hard shell takes a lot of energy, Li said. She suspects that by relying on such a symbiotic relationship with shrimp and sponges, moon clams no longer need to invest as much in building their shells. Instead, the clam seems to have redirected that energy to a different task: sensing the world. Their mantle, the soft flesh that typically lines a clam's shell, extends outward and folds over the shell surface. There are small bumps and tentacle-like structures all over the mantle, and Li said these may act as sensory organs, helping the animal detect changes in its environment through touch or chemical signals.
