Seastars

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(5 total)

Ophiuroid
© 2004 Roger Portell, Florida Museum of Natural History

Onychaster flexilis
© 2005 The Virtual Fossil Museum

Henricia venturana
© 2006 The Virtual Fossil Museum

What are Seastars? Two different groups of echinoderms are often lumped together as “sea stars:”

True sea stars (Asteroidea) have tube feet used for locomotion and capturing prey. The asteroids are the oldest members of this group, appearing in the Ordovician.
Brittle stars (Ophiuroidea) move by wriggling their slender, snaky arms. Brittle stars have a distinctive central disk-shaped body.

First known fossil occurrence: Ordovician.

Last known fossil occurrence: Quaternary. This group has living relatives.

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