Crinoids on a rock wall - Vidéo 4K

Two crinoids on a rocky overhang. Crinoids are echinoderms, relatives of starfish. They filter plankton from the currents with their feathery arms. They have remained essentially unchanged for some 460 million years, with fossils from the Ordovician closely resembling modern forms. Filmed on the Great Barrier Reef, Australia.