Long-spined Sea Urchin

Diadema antillarum

''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.

This sea urchin is characterized by its exceptionally long black spines.

It is the most abundant and important herbivore on the coral reefs of the western Atlantic and Caribbean basin. When the population of these sea urchins is at a healthy level, they are the main grazers which prevent algae overgrowth of the reef.
The Long spine goodnight (sharper than I look) You don't want to step into me as I will protect myself. Did you know fish like the endangered species Banggai Cardinal have discovered I also protect their eggs? The male fish carry their eggs into their mouths for 4 weeks. Then, when they grow bigger, they spit them between my spines. Thus helping my friends to survive. Even without hard labor. Diadema antillarum,Geotagged,Long-spined Sea Urchin,United Kingdom

Appearance

''Diadema antillarum'' has a test, or "shell," similar to most other sea urchins. What distinguishes the ''Diadema'' is the length of its spines. Most sea urchin spines are 1–3 cm, but the spines in this species are usually 10–12 cm in length, and can grow as long as 30 cm in very large individuals.
Sea urchin Diadema antillarum,Long-spined Sea Urchin

Naming

Research on the species ''Diadema antillarum'' is still in its early stages. The urchins can be grown in laboratories and then relocated. Returning the mature individuals into the wild can have a positive effect on the urchin density of the reef. The increase in population can also be aided by the artificial building of reefs: material such as concrete can encourage the growth of coral, and provide more niches for the urchins to hide from predators such as larger fish.

When there are still some areas of high-density urchins, it is possible to relocate urchins to other, low-density reefs. With these methods and the help of volunteer workers, it seems that the shift back to coral-dominated reefs and away from algae-dominated reefs is possible.

When re-locating Diadema it is necessary to remove most mature algae from the re-location area since there are toxins in mature algae that kills the Diadema.
Long-Spined Sea Urchin Sep 14, night dive in Bari Reef, Bonaire. Diadema antillarum is a regular (round) urchin, and displays the pentamerism of echinoderms. Mature individuals of D. antillarum can reach up to 500 mm in diameter. Diadema antillarum has thin spines that range from 300-400 mm in length and can be up to four times the diameter of the test (skeleton formed inside the body). The spines are thin, hollow, and break easily. The test is rigid and there is a reduced amount of soft tissue in the body wall as compared to other species in the family Diadematidae. The test and spines of a mature adult are typically black, but lighter colored spines may be intermixed, and in rare cases the urchin will be almost entirely white. The spines of juveniles are always banded with black and white. When the urchin dies, the spines falls off and the test remains. At the base of the urchin are branched tentacles called tube feet, which help in gathering food, respiration, locomotion, and mucous production. http://animaldiversity.org/accounts/Diadema_antillarum/ Caribbean Netherlands,Diadema antillarum,Geotagged,Long-spined Sea Urchin,Summer

Distribution

Research on the species ''Diadema antillarum'' is still in its early stages. The urchins can be grown in laboratories and then relocated. Returning the mature individuals into the wild can have a positive effect on the urchin density of the reef. The increase in population can also be aided by the artificial building of reefs: material such as concrete can encourage the growth of coral, and provide more niches for the urchins to hide from predators such as larger fish.

When there are still some areas of high-density urchins, it is possible to relocate urchins to other, low-density reefs. With these methods and the help of volunteer workers, it seems that the shift back to coral-dominated reefs and away from algae-dominated reefs is possible.

When re-locating Diadema it is necessary to remove most mature algae from the re-location area since there are toxins in mature algae that kills the Diadema.

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