The Echinoblog: Crinoid Close ups!

Crinoids, aka Feather stars are probably the least familiar of echinoderms to many people. They've been around for awhile and you can often see their older Paleozoic ancestors with stalks in fossil beds throughout the world.

But most modern crinoids almost resemble plants (albeit stunning ones). The picture above shows a typical "feather star" or comatulid crinoid. The arms have feathery appendages called pinnules which are used for capturing food.

To give you some reference.. here's a generalized diagram. Food goes into the mouth located on the "inside" of the cup where the arms meet.

Image from lander.edu

I've often tried to make several echinoderms more "visible" to people by sharing some incredible imagery of them-from perspectives that might be unfamiliar. Some of my posts on ophiuroids here and here for example...

Here is a very busy picture of the many structures surrounding the MOUTH (at center covered by more tentacles) (critter from Fiji) (image by Jaw'sDad-Jeff Williams):

Here's a great picture of the UNDERSIDE of a feather star. See those tentacle-like things wrapped around the whip coral? Those are called "cirri". Those are the "feet" that adhere the remainder of the animal to its perch. This image by "sabahsharky"

Blue Crinoid Close up.. from Sulawesi, Indonesia. These are the feeding arms with yellow tipped extensions called pinnules. Image by Richard Merritt, FRPS.