| Echinometra viridis | |
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| Echinometra viridis | |
| Scientific classification | |
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| Species: | E. viridis |
| Binomial name | |
| Echinometra viridis A. Agassiz, 1863 [1] | |
| Synonyms [1] | |
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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.
The reef urchin has an elliptical reddish brown test (shell) covered with medium length spines. These are greenish in colour with paler bases and darker, often violet, tips. This urchin grows to a diameter of 5 centimetres (2.0 in) with the longest spines being 3 centimetres (1.2 in). [2] It looks very similar to the rock-boring urchin Echinometra lucunter , but the dark tips and the greater length of the spines are distinctive. [3]
The reef urchin is found on reefs in the Caribbean Sea from southern Florida to Venezuela at depths down to about 15 metres (49 ft). It is not as common as the rock-boring urchin and seems to be absent from the West Indies to the east of the Virgin Islands. [3]
The reef urchin conceals itself in crevices or under boulders. It emerges at night to feed by grazing on algae with its five teeth, part of the Aristotle's lantern organ that surrounds its mouth. [4] It is not believed to bore holes, but its grazing still causes bioerosion in reefs. [5] In Panama, breeding takes place during the period April to December. It does not seem to be correlated with the phases of the moon as in some other sea urchin species. [6] Fertilisation is external and the echinopluteus larvae are planktonic. When these settle, they undergo a rapid metamorphosis into juvenile sea urchins. [4]
Researchers have studied the likely effect on the reef urchin of a rise in the carbon dioxide levels which are likely to increase ocean acidification by the end of the 21st century. It was found that the urchins would be negatively impacted because of decreased calcification, lowering their ability to build their tests, especially during winter and in the more northerly parts of their range. [7]
The reef urchin is an important grazer on fleshy algae in the Caribbean area. Its abundance is reduced by predation by fish, especially the jolthead porgy ( Calamus bajonado ), the queen triggerfish ( Balistes vetula ), the ocean triggerfish ( Canthidermis sufflamen ) and the hogfish ( Lachnolaimus maximus ). Because of this predation, the reef urchin avoids open reef flats and in these locations there is an overgrowth of fleshy algae. It is unable to take over the algal controlling role of the black sea urchin ( Diadema antillarum ) which is subject to great fluctuations in population. [8]
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.
Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of red, but some species can be purple, yellow, blue, white, or gray-green. Coralline algae play an important role in the ecology of coral reefs. Sea urchins, parrot fish, and limpets and chitons feed on coralline algae. In the temperate Mediterranean Sea, coralline algae are the main builders of a typical algal reef, the Coralligène ("coralligenous"). Many are typically encrusting and rock-like, found in marine waters all over the world. Only one species lives in freshwater. Unattached specimens may form relatively smooth compact balls to warty or fruticose thalli.
The diadema urchin or blue-black urchin is a species of tropical sea urchin, member of the Diadematidae family.
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.
Lytechinus variegatus, commonly called the green sea urchin or the variegated sea urchin, is a species of sea urchin that can be found in the warm waters of the western Atlantic Ocean and Caribbean Sea.
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.
Tripneustes ventricosus, commonly called the West Indian sea egg or white sea urchin, is a species of sea urchin. It is common in the Caribbean Sea, the Bahamas and Florida and may be found at depths of less than 10 metres (33 ft).
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.
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.
Aspidodiadema jacobyi is a small sea urchin in the family Aspidodiadematidae. It lives in tropical seas at great depths. Aspidodiadema jacobyi was first scientifically described in 1880 by Alexander Emanuel Agassiz, an American scientist.
Lytechinus williamsi, the jewel urchin, is a sea urchin in the family Toxopneustidae. It occurs on shallow reefs off the coasts of Panama, Belize, the Florida Keys and Jamaica.
Echinometra is a genus of sea urchins in the family Echinometridae.
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.
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.
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.
Diadema mexicanum is a species of long-spined sea urchin belonging to the family Diadematidae. It is native to the Pacific coast of Mexico, Costa Rica, El Salvador, Nicaragua and Panama.
Diadema savignyi is a species of long-spined sea urchin belonging to the family Diadematidae. Common names include long-spined sea urchin, black longspine urchin and the banded diadem. It is native to the east coast of Africa, the Red Sea, the Indian Ocean and western Pacific Ocean. It was first described in 1829 by the French naturalist Jean Victoire Audouin. The specific epithet honours the French zoologist Marie Jules César Savigny who described many new marine species from the Mediterranean Sea and Red Sea. The type locality is Mauritius.
Tetrapygus is a genus of sea urchins in the family Arbaciidae. It is a monotypic genus and the only species is Tetrapygus niger which was first described by the Chilean naturalist Juan Ignacio Molina in 1782. It is found in the southeastern Pacific Ocean on the coasts of South America.
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