Tripneustes ventricosus
| Tripneustes ventricosus | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Order: | Camarodonta |
| Family: | Toxopneustidae |
| Genus: | Tripneustes |
| Species: | T. ventricosus |
| Binomial name | |
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Tripneustes ventricosus (Lamarck, 1816) |
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| Synonyms | |
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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).
The test of the West Indian sea egg is dark in color, usually black, dark purple or reddish brown, with white spines 1 to 2 centimetres (0.4 to 0.8 inches) long. The test can reach 10 to 15 centimetres (3.9 to 5.9 in) in diameter. It is often covered with pieces of seagrass, fragments of shell and other debris in a manner similar to the closely related Tripneustes gratilla. These decorations are held in place by tube feet among the spines and are believed to provide protection from the intense sunlight that penetrates the shallow water.
The West Indian sea egg is found in shallow parts of the western Atlantic Ocean, the Caribbean Sea and Gulf of Mexico. Its range extends from Bermuda, the Carolinas and Florida to Belize, Venezuela and Brazil and also includes the west coast of Africa and Ascension Island. It seldom occurs in water deeper than 10 metres (33 ft). It is found in seagrass meadows, in rubble areas and on shallow rocky reefs. Young sea urchins conceal themselves in crevices and under rocks during the day but larger individuals stay out in the open.
The West Indian sea egg feeds on algae but tends to avoid the crustose, highly calcified coralline algae.
Ripe gonads were found in urchins at any time of year but breeding probably takes place mostly in the summer. Male and female urchins liberate gametes into the sea where fertilisation takes place. The eggs soon hatch into larvae which are planktonic. These develop through a number of larval stages over the course of about one month before settling on the seabed and undergoing metamorphosis into juveniles. Young urchin recruits in Barbados are thought to have originated off the coast of South America. Various bottom feeding fish feed on the young sea urchins. In Jamaica, the queen triggerfish, (Balistes vetula), is the main predator. During their first year, young urchins increased their diameter by about 7 millimetres (0.28 in) a month. Growth rates slowed down thereafter and growth halted completely after maturity was reached while the gonads were ripening. After liberation of the gametes, growth restarted.
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Wikipedia