Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin are distributed on the seabeds of every ocean and inhabit every depth zone from the intertidal seashore down to 5,000 meters. The spherical, hard shells (tests) of sea urchins are round and covered in spines. Most urchin spines range in length from 3 to 10 cm, with outliers such as the black sea urchin possessing spines as long as 30 cm (12 in). Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals, and humans.
Echinothrix calamaris, known commonly as the banded sea urchin or double spined urchin among other vernacular names, is a species of sea urchin in the family Diadematidae.
Diadema antillarum, also known as the lime urchin, black sea urchin, or the long-spined sea urchin, is a species of sea urchin in the family Diadematidae.
The orange-lined triggerfish is a demersal triggerfish. Although Balistapus is a monotypic genus, it is closely related to the genus Balistoides.
Diadema setosum is a species of long-spined sea urchin belonging to the family Diadematidae. It is a typical sea urchin, with extremely long, hollow spines that are mildly venomous. D. setosum differs from other Diadema with five, characteristic white dots that can be found on its body. The species can be found throughout the Indo-Pacific region, from Australia and Africa to Japan and the Red Sea. Despite being capable of causing painful stings when stepped upon, the urchin is only slightly venomous and does not pose a serious threat to humans.
Centrostephanus coronatus, also known as crowned sea urchin, is a species of sea urchin in the family Diadematidae. It was first described to science by Yale zoology Professor Addison Emery Verrill in 1867.
Colobocentrotus atratus, commonly named the helmet urchin or shingle urchin, is a species of sea urchin in the family Echinometridae. In Hawaii, it is called hāʻukeʻuke. It is found on wave-swept intertidal shores in the Indo-West Pacific, particularly on the shores of Hawaii.
Hemicentrotus pulcherrimus is a species of sea urchin, the only one in the monotypic genus Hemicentrotus. It was first described by the American engineer and marine zoologist Alexander Agassiz in 1864 as Psammechinus pulcherrimus. Its range extends along the coasts of Korea and China, and in Japan from Kyūshū to Ishikari Bay. An edible species, it is harvested from Kyūshū to Fukui, in the Sea of Japan.
Heterocentrotus mamillatus, commonly known as the slate pencil urchin, red slate pencil urchin, or red pencil urchin, is a species of tropical sea urchin from the Indo-Pacific region.
Arbacia lixula, the black sea urchin, is a species of sea urchin from Europe.
Tripneustes gratilla, the collector urchin, is a species of sea urchin. Collector urchins are found at depths of 2 to 30 metres in the waters of the Indo-Pacific, Hawaii, the Red Sea, and The Bahamas. They can reach 10 to 15 centimetres in size.
Argiope pulchella is a species of the orb-weaver spider family, Araneidae. It ranges from India to China and can be found on Java. It is a synanthropic species, often living in habitats associated with humans.
Toxopneustes pileolus, commonly known as the flower urchin, is a widespread and commonly encountered species of sea urchin from the Indo-West Pacific. It is considered highly dangerous, as it is capable of delivering extremely painful and medically significant stings when touched. It inhabits coral reefs, seagrass beds, and rocky or sandy environments at depths of up to 90 m (295 ft). It feeds on algae, bryozoans, and organic detritus.
Echinometra mathaei, the burrowing urchin, is a species of sea urchin in the family Echinometridae. It occurs in shallow waters in the Indo-Pacific region. The type locality is Mauritius.
Echinometra lucunter, the rock boring urchin, is a species of sea urchin in the family Echinometridae. It is found in very shallow parts of the western Atlantic Ocean and the Caribbean Sea.
Echinometra viridis, the reef urchin, is a species of sea urchin in the family Echinometridae. It is found on reefs in very shallow parts of the western Atlantic Ocean and the Caribbean Sea.
Diadema paucispinum, the long-spined sea urchin, is a species of sea urchin in the family Diadematidae. It is found in the western Indo-Pacific Ocean and in Hawaii and other east Pacific islands.
Athanas areteformis is a species of small alpheid shrimp from the Indo-West Pacific.
Echinometra oblonga, also called the oblong urchin or 'ina 'ele 'ele in Hawaiian, is a very common rock boring urchin on shallow rocky shores of the tropical Indo-Pacific and Southern Africa.
