Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone — from the intertidal seashore down to 5,000 metres. The spherical, hard shells (tests) of sea urchins are round and spiny, ranging in diameter from 3 to 10 cm. 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. In the food chain, the predators who eat sea urchins are the sea otter and the starfish, the wolf eel, the triggerfish, and human beings.
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.
Aeoliscus strigatus, also known as the razorfish, jointed razorfish or coral shrimpfish, is a member of the family Centriscidae of the order Syngnathiformes. This unique fish adopts a head-down tail-up position as an adaptation for hiding among sea urchin spines. The razorfish is found in coastal waters in the Indo-West Pacific. Its natural habitat includes beds of sea grass and coral reefs, where sea urchins are found.
The long-spine porcupinefish, also known as the freckled porcupinefish among other vernacular names, is a species of marine fish in the family Diodontidae.
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Strongylocentrotus droebachiensis is commonly known as the green sea urchin because of its characteristic green color. It is commonly found in northern waters all around the world including both the Pacific and Atlantic Oceans to a northerly latitude of 81 degrees and as far south as Maine and England. The average adult size is around 50 mm (2 in), but it has been recorded at a diameter of 87 mm (3.4 in). The green sea urchin prefers to eat seaweeds but will eat other organisms. They are eaten by a variety of predators, including sea stars, crabs, large fish, mammals, birds, and humans. The species name "droebachiensis" is derived from the name of the town Drøbak in Norway.
The golden grouper, also known as the pink grouper or Powell's grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. It is found in the eastern Indian Ocean and Western Pacific Ocean.
Lutjanus sebae, also known as red emperor, emperor red snapper, emperor snapper, government bream, king snapper, queenfish or red kelp, is a species of marine ray-finned fish, a snapper belonging to the family Lutjanidae. It is native to the Indian Ocean and the western Pacific Ocean.
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.
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.
Blennioclinus brachycephalus, the Lace klipfish, is a species of clinid found in subtropical waters of the Atlantic Ocean around South Africa. This species can reach a maximum length of 15 centimetres (5.9 in) TL. This species primarily preys on benthic fauna including isopods, amphipods, and mollusks.
Echinocardium cordatum, also known as the common heart urchin or the sea potato, is a sea urchin in the family Loveniidae. It is found in sub-tidal regions in the NE Atlantic. Other un-named species have been identified as this species from temperate seas around the world. It lives buried in the sandy sea floor.
Abatus cordatus is a species of sea urchin in the family Schizasteridae. It is native to shallow seas surrounding certain island groups in the southern Indian Ocean. The body is protected by a hard test or shell which is covered with spines. The female broods its young in deep pockets on the upper surface, retaining the young in place with specialised spines. American zoologist Addison Emery Verrill first scientifically described A. cordatus in 1876.
Sterechinus neumayeri, the Antarctic sea urchin, is a species of sea urchin in the family Echinidae. It is found living on the seabed in the waters around Antarctica. It has been used as a model organism in the fields of reproductive biology, embryology, ecology, physiology and toxicology.
Dorippe frascone, the urchin crab or carrier crab, is a small species of crab in the family Dorippidae that was first described scientifically by J.F.W. Herbst, in 1785. It is found in the Red Sea and parts of the western and eastern Indian Ocean. It often has a symbiotic relationship with a long-spined sea urchin and carries one around on its carapace.
Eucidaris metularia, the ten-lined urchin, is a species of sea urchins in the family Cidaridae. It is found in shallow parts of the Indo-Pacific Ocean and is characterised by its sparse covering of banded, flat-tipped spines.
Lytechinus pictus, commonly known as the painted urchin, is a sea urchin in the family Toxopneustidae. It occurs on shallow reefs in the tropical and subtropical eastern Pacific Ocean, off the coasts of California, Central America and South America as far south as Ecuador.
Aspasmogaster costata, the eastern clingfish or pink clingfish is a species of clingfish from the family Gobiesocidae. It is endemic to eastern Australia where it occurs from Byron Bay to the Nadgee Nature Reserve in southern New South Wales and also on Lord Howe Island in the Tasman Sea. This is a secretive species which frequently hides under rocks, shelters in crevices or behind sea urchins at depths down to 20 metres (66 ft). The species was described in 1885 by James Douglas Ogilby with a type locality of Shark Reef near Port Jackson in New South Wales.
Helicolenus barathri, the bigeye sea perch, bigeye ocean perch, coral cod, coral perch, red gurnard perch, red perch or red rock perch, is a species of marine ray-finned fish belonging to the subfamily Sebastinae, part of the family Scorpaenidae. It is found in the southwestern Pacific Ocean.
