Spiny Cattle Stars

Ophiothrix spiculata (a.k.a. spiny brittle stars) are the most diverse organisms in phylum Echinodermata that can be found in the ocean all over the world. They are spotted in many different colors such as orange, yellow, red, blue, black, or even tanned with reddish and white bands on their arms. Most spiny brittle stars have either round or star-shape body that are usually not larger than three centimeters. The body is called the central disk which consists of the dorsal shield (aboral side) and oral shield (oral side.) Unlike sea stars in class Asteroidea, spiny brittle stars have unbranched arms that are setting off from the central disk. Each arm is covered with large, well-developed ossicles called spines—spines are made up of calcium …show more content…
However, unlike sea stars, their madreporite locate at the oral side where the mouth is. They exchange gases such as oxygen (O2) and carbon dioxide (CO2) in special pockets known as membranous sacs called bursae. The bursae are lined up in a circle around the central disk at the base of each arm; the bursae consist of exhalant bursal slit and inhalant bursal slit. Cilia are attached around the bursae that are not only move water in and out but also release waste product such as ammonia out of the bursae …show more content…
Nevertheless, breeding has been noted to happen during summer time around May to July at the Pacific Grove in California. Spawning takes place once per breeding season (Ophiothrix SIMoN.) Spiny brittle stars hold no gestation because sperms and eggs are respectively released into water, where the fertilized eggs go through early development and develop into larvae (Hunt.) As stated, even though the eggs and sperms are sometimes retained in the bursae, the fertilized eggs are released into the plankton and invest no parental care. When the eggs hatch, ophioplutei feed themselves for several weeks on plankton and go through metamorphosis to fully develop into adult brittle stars (Brittle