Diadema savignyi

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Diadema savignyi
Diadema savignyi1.jpg
Diadema savignyi
Scientific classification
Kingdom:
Animalia
Phylum:
Echinodermata
Class:
Echinoidea
Order:
Diadematoida
Family:
Diadematidae
Genus:
Diadema
Species:
D. savignyi
Binomial name
Diadema savignyi
(Audouin, 1829) [1]
Synonyms
  • Centrechinus savignyi (Audouin, 1829)
  • Centrostephanus savignyi (Audouin, 1829)
  • Cidarites savignyi Audouin, 1829
  • Diadema globulosum Bölsche, 1865

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. [2] The type locality is Mauritius. [1]

Sea urchin Class of echinoderms

Sea urchins, or simply urchins, are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal to 5,000 metres. Their tests are round and spiny, typically from 3 to 10 cm across. Sea urchins move slowly, crawling with their tube feet, and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessile animals. Their predators include sea otters, starfish, wolf eels, and triggerfish.

Diadematidae family of echinoderms

The Diadematidae are a family of sea urchins. Their tests are either rigid or flexible and their spines are long and hollow.

Marie Jules César Lelorgne de Savigny was a French zoologist.

Contents

Description

Diadema savignyi D. savignyi bicolore.jpg
Diadema savignyi

Diadema savignyi has a usually black, spherical, slightly-flattened test up to about 9 cm (3.5 in) in diameter. The brittle, thin, hollow spines grow in tufts and can be as long as 25 cm (10 in). They are usually black but can also be grey, dark brown or purple. They may be banded with lighter and darker shades in juveniles and the occasional individual sea urchin is completely white. [2] Diadema savignyi is similar in appearance to the closely related Diadema setosum with which it is sympatric, that is, the two species share a common range and frequently come into contact with each other. [3] Diadema savignyi can be distinguished by the fact that it has iridescent green or blue lines in the interambulacral areas and around the periproct, a cone-shaped region surrounding the anus. In a small number of individuals there are pale coloured spots at the aboral (upper) ends of the interambulacrals. Another distinguishing feature is that D. savignyi does not have a thin orange ring round the periproct whereas D. setosum does. [4]

Test (biology) hard shell of some spherical marine animals, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae

In biology, a test is the hard shell of some spherical marine animals, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds.

<i>Diadema setosum</i> species of sea urchin

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.

Sympatry existence of two species within the same geographic region

In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation does not imply secondary contact, which is speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed.

Distribution and habitat

The range of Diadema savignyi extends from the eastern coast of Africa and the Red Sea to French Polynesia, Hawaii, New Caledonia and northern Australia. It is typically found on mixed sandy, rocky and coral substrates especially in areas disturbed by storms or by other natural causes. Its depth range is from the surface down to about 70 metres (230 ft). [2]

In biology, a substrate is the surface on which an organism lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be itself a substrate for an animal that lives on top of the algae.

Biology

Diadema savignyi is nocturnal and tends to hide in crevices or under boulders during the day, or several individuals may huddle together in the open. The urchins disperse at dusk to feed on the algal mat that grows over the surface of seabed. In the course of tearing up the mat the urchin also abrades the underlying surface, causing bioerosion. Its activities help control the algae which otherwise might overwhelm the corals. [2] Certain small fish such as cardinal fish, flatworms and shrimps sometimes seek protection from predators among the long spines. The sea urchin is preyed on by pufferfish (Tetraodontidae) and porcupinefish (Diodontidae), and also lobsters and snails. It reacts to a shadow falling on it by angling its spines towards the possible attacker. [2]

Nocturnality animal behavior characterized by activity during the night and sleeping during the day

Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.

Bioerosion Erosion of hard substrates by living organisms

Bioerosion describes the breakdown of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and fish; it can occur on coastlines, on coral reefs, and on ships; its mechanisms include biotic boring, drilling, rasping, and scraping. On dry land, bioerosion is typically performed by pioneer plants or plant-like organisms such as lichen, and mostly chemical or mechanical in nature.

Flatworm Phylum of animals, flatworms

The flatworms, flat worms, Platyhelminthes, Plathelminthes, or platyhelminths are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Unlike other bilaterians, they are acoelomates, and have no specialized circulatory and respiratory organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion and egestion ; as a result, the food cannot be processed continuously.

Diadema savignyi and Diadema setosum live in close proximity and often in mixed groups on reefs and in shallow lagoons off the coast of East Africa. The latter breeds throughout the year, but breeding in D. savignyi is concentrated and occurs mainly during the north-east monsoon period, peaking in May. Hybridisation between the two species is largely prevented by the fact that the release of gametes by each is synchronised with the lunar cycle. D. savignyi spawns just after the full moon, on days seventeen to eighteen of the lunar cycle, whereas D. setosum mostly spawns around days eight to ten. [3]

Monsoon seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea

Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is sometimes incorrectly used for locally heavy but short-term rains.

Hybrid (biology) offspring of cross-species reproduction

In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents, but can show hybrid vigour, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are.

Gamete haploid cell that fuses with another haploid cell during fertilization (conception) in organisms that sexually reproduce

A gamete is a haploid cell that fuses with another haploid cell during fertilization in organisms that sexually reproduce. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete—called an ovum— and a male produces the smaller tadpole-like type—called a sperm. In short a gamete is an egg cell or a sperm. This is an example of anisogamy or heterogamy, the condition in which females and males produce gametes of different sizes. In contrast, isogamy is the state of gametes from both sexes being the same size and shape, and given arbitrary designators for mating type. The name gamete was introduced by the Austrian biologist Gregor Mendel. Gametes carry half the genetic information of an individual, one ploidy of each type, and are created through meiosis.

Related Research Articles

<i>Echinothrix diadema</i> species of echinoderm

The diadema urchin or blue-black urchin is a species of tropical sea urchin, member of the Diadematidae family.

<i>Echinothrix</i> genus of echinoderms

Echinothrix is a genus of sea urchins which was first described in 1853 by Wilhelm Peters, a German naturalist and explorer.

<i>Echinothrix calamaris</i> species of echinoderm

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.

<i>Diadema</i> (genus) genus of sea urchin

Diadema is a genus of sea urchins of the Family Diadematidae.

<i>Diadema antillarum</i> species of sea urchin

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.

Meoma ventricosa, known by the common names cake urchin and red heart urchin, is a large species of sea urchin which lives in shallow waters in the Caribbean. It may reach a diameter of twenty centimeters and is covered in reddish-brown spines. It has both pentagonal radial symmetry and bilateral symmetry, giving it a sand-dollar appearance; however, two of its five sections are merged more closely than the others.

<i>Heterocentrotus mamillatus</i> Species of echinoderm

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.

<i>Toxopneustes pileolus</i> species of echinoderm

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.

<i>Echinometra mathaei</i> species of echinoderm

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.

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.

<i>Echinometra lucunter</i> species of echinoderm

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.

Phormosoma placenta is a species of sea urchin in the order Echinothurioida. It is a deepwater species, seldom being found at depths less than 500 m (1,600 ft), and occurs on either side of the Atlantic Ocean on the continental slope.

<i>Dorippe frascone</i> species of crustacean

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.

<i>Diadema paucispinum</i> species of sea urchin

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.

<i>Diadema mexicanum</i> species of sea urchin

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.

<i>Toxopneustes elegans</i> species of echinoderm

Toxopneustes elegans is a species of sea urchin endemic to Japan. Like the closely related flower urchin, they are venomous.

References

  1. 1 2 Kroh, Andreas (2013). Kroh A, Mooi R (eds.). "Diadema savignyi (Audouin, 1829)". World Echinoidea Database. World Register of Marine Species . Retrieved 2013-11-23.
  2. 1 2 3 4 5 Le Bris, Sylvain; Didierlaurent, Sylvie (2013-09-06). "Diadema savignyi (Audouin, 1829)". DORIS (in French). Retrieved 2013-11-23.
  3. 1 2 Muthiga, N. A. (2003). "Coexistence and reproductive isolation of the sympatric echinoids Diadema savignyi Michelin and Diadema setosum (Leske) on Kenyan coral reefs". Marine Biology. 143 (4): 669–677. doi:10.1007/s00227-003-1095-7.
  4. ↑ Coppard, Simon Edward; Campbell, Andrew C. (2006). "Taxonomic significance of test morphology in the echinoid genera Diadema Gray, 1825 and Echinothrix Peters, 1853 (Echinodermata)" (PDF). Zoosystema. 28 (1): 93–112. Archived from the original (PDF) on 2006-11-27. Retrieved 2009-01-12.
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