Hobbies And Interests
Identification
The Astropyga radiata is a large species of sea urchin with long, sharp, mobile spines. Sea urchins live on the sandy and rocky bottoms of bays and lagoons around the Indian and Pacific oceans. They are colorful creatures, with orange, white and red bands around their dark spines and bright blue dots on their bodies. It lives in harmony with small fish and crabs, which find solace from predators among the urchins' spines. In return, crabs often provide the urchins with transportation on their backs. Their spines are venomous, and stings are highly painful and might require medical attention.
Order/Family
The Astropyga radiata belongs to the superorder Diadematacea, which includes several species of sea urchins. Sea urchins in this superorder differ from other sea urchins largely through their long, hollow spines. Within that superorder, its order is Diadematoida and its family is Diadematidae. One of the more common types of sea urchin within this order and family is the widely abundant Diadema urchin, which lives in shallow waters and along reefs. Urchins in this order are vital to the survival of coral reefs, dining on tiny algae that otherwise would overtake the reef.
Class
Like all sea urchins, the Astropyga radiata belongs to the class Echinoidea. Urchins within this class can range from a few millimeters in diameter to more than a foot across. The sand dollar also is in this class. In total, there are about 940 species within this class, and they date back hundreds of millions of years. Most creatures in this class are symmetrical, protected by shells of tightly packed plates and tiny tubed feet to let them move. They have a simple digestive system, consisting of a mouth, intestine and an anus.
Phylum
The Astropyga radiata is in the phylum Echinodermata, which includes about 7,000 species found throughout the ocean. Besides sea urchins and and sand dollars, the phylum also includes starfish, sea cucumbers and sea lilies. All echinoderms live in salt water. They also share the traits of symmetrical bodies and a water vascular system that allows them to move via their tubed feet and capture prey. They've been on the earth more than 500 million years, with the earliest known fossils dating back to the early Cambrian period.