Ron's Critter of the Day

TAXONOMY
Phylum: Echinodermata
Class: Crinoidea (Sea Lilies and Feather Stars)
Order: Comatulida
Family: Antedonidae

Genus/species: Florometra serratissima

GENERAL CHARACTERISTICS: Tan to reddish tan. Like an upside-down brittle star. The 5 arms often fork near the base to form a total of 10 or more arm branches which are often around 10 cm (4 inches) long. Jointed appendages called pinnules branch from the side of the arms, giving the featherlike appearance. The upper (oral) surface of the arms has an ambulacral groove, and both the mouth and the anus are on the upper side of the central disk. The aboral side of the central disk has clawlike cirri which function somewhat like bird feet to grasp the substrate. Armspread to 25 cm (10 inches).

DISTRIBUTION/HABITAT: Alaska to Mexico or farther south to off South America in deep water in a current.  Depth 10-1252 m (32-4100 feet) 

DIET IN THE WILD: Suspension feeders of plankton  The food transport system of the crinoids extends out on to the arms, or the “feathers,” of the feather star.  It subdivides and continues out into the lateral small projections off the main arm and consists of a mucous-filled ciliated food groove which connects all the way to from the finest arm branch to the mouth on the upper surface of the body. Out on the fine branches, or pinnules, of each arm, the food groove has a row of tube feet on each side of it.  Crinoid tube feet neither work as independent units nor are they used in locomotion. Rather they are used only for feeding, and they work as groups of six, divided into two groups of three tube feet each, on opposite sides of the food groove. These tube feet extend directly up from the animal’s surface into the water.

PREDATORS: Various fishes.

REPRODUCTION: Comatulids are dioecious, each individual being either male or female. Gametes are produced in pinnules at the base of the arms, with external fertilisation. The larvae are planktonic settling on the seabed anchoring themselves with a stalk.
The stalk breaks and the juveniles can move around after metamorphosis.

REMARKS:  Possess the water-vascular system and tube feet that are characteristic of this phylum; however, unlike most other echinoderms, they do not use the tube feet for locomotion. If they need to move more rapidly, perhaps to escape a predator, they release the grip of the cirri and, using a particularly beautiful undulatory motion of the arms, they propel themselves up into the water, swimming for short distances. 

Crinoids, like all other echinoderms, lack even a rudimentary brain, and the nervous system is difficult to see. Nonetheless, they have good sensory capabilities, with millions of small sensory cells located throughout there skin.

LOCATION; California Rocky Reef

References

Encyclopedia of life eol.org/pages/597860/details

Walla Walla University http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Echinodermata/Class_Crinoidea/Florometra_serratissima.html

Ron’s flickr  http://www.flickr.com/photos/cas_docents/sets/72157608501343477/

Ron’s WordPress shortlink  http://wp.me/p1DZ4b-g7