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How do tusk shells capture tiny prey in sandy sediments?
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mollusk
Mollusk shell classification chart, c. 1861.
Tusk shells (class Scaphopoda) capture tiny prey, such as protozoans and young bivalves, using specialized organs called captacula.1
These slender, tentacle-like structures are located at the anterior end of the animal, which is typically buried in sandy sea-bottom sediments. The captacula serve as both sensory and food-catching organs, extending into the surrounding sediment to secure prey.1