Marine Biology 10th Edition by Peter Castro,Michael Huber

Exercise 3

A new group of echinoderms, the sea daisies, or concentricycloids, was discovered in 1986. They are deep-water animals living on sunken wood. They are flat and round, looking very much like a small sea star without arms. They also lack a gut. Without ever having seen them, why do you think they were classified as echinoderms, not as members of a new phylum? Do you have any hypotheses as to how they feed or move around?