With their long stalks and feathery arms, marine animals known as sea lilies look a lot like their garden-variety namesakes. Perhaps because of that resemblance, scientists had always assumed that sea lilies stayed rooted instead of moving around like their stalkless relatives, the feather stars.
But videos taken from a submersible research vessel at a depth of 430 meters (1410 feet) near Grand Bahama Island reveal that some sea lilies can creep along the ocean floor, apparently to escape from sea urchins that prey upon them. The video and related studies help paint a bigger picture of the evolution and ecology of these deep-sea creatures and their predators.
University of Michigan professor of geological sciences Tomasz Baumiller will show the videos and discuss the research Oct.16 at a meeting of the Geological Society of America in Salt Lake City, Utah.
Sea lilies and feather stars, members of a group called crinoids, are closely related to starfish, sea cucumbers and sea urchins. The two main types of crinoids look a lot alike except that sea lilies have stalks, and feather stars do not. In addition, feather stars are known to crawl, and some can even swim, but sea lilies were thought not to have such abilities.
However, Baumiller and collaborator Charles Messing of Nova Southeastern University's Oceanographic Center in Dania Beach, Fla., have long suspected that some sea lilies are able to move around. In previous work, the researchers found that some sea lilies regularly shed and regenerate the ends of their stalks. Interestingly, the stalks don't break off just anywhere, but at particular nodes, just below clusters of flexible, finger-like appendages. Baumiller and Messing speculated that the sea lilies might be shedding the ends of their stalks to release themselves from the pla
Source:University of Michigan