Cidaridae is a family of

sea urchin 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 . The spherical, hard shells (tests) ...

s in the order

Cidaroida Cidaroida is an order of primitive sea urchins, the only living order of the subclass Perischoechinoidea. All other orders of this subclass, which were even more primitive than the living forms, became extinct during the Mesozoic. Description T ...

Description and characteristics

Cidarid sea urchins are characterized by their stout skeleton : the

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ...

is thick and hard, with massive perforated tubercles (never crenulated) surrounded by a crown of secondary tubercles, but no primary tubercles in the interambulacra regions. These tubercles hold massive spines, thick, strong and often very long, and showing sometimes odd shapes (thorny spines, fans, clubs, Christmas trees...). The order

is the basalmost of current sea urchins, and most of the species included in this family are abyssal, even if a handful of species remain quite common in tropical shallow waters, like '' Eucidaris'' or '' Phyllacanthus''.

Genera

According to the

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific speciali ...

(WoRMS), the following genera are included in this family * Subfamily '' Cidarinae'' (Mortensen, 1928a) ** Genus '' Calocidaris'' (H.L. Clark, 1907) ** Genus '' Centrocidaris'' (A. Agassiz, 1904) ** Genus '' Chondrocidaris'' (A. Agassiz, 1863) ** Genus '' Chorocidaris'' (Ikeda, 1941) ** Genus '' Cidaris'' (Leske, 1778) ** Genus '' Compsocidaris'' (Ikeda, 1939) ** Genus '' Eucidaris'' (Pomel, 1883) ** Genus '' Hesperocidaris'' (Mortensen, 1928b) ** Genus '' Kionocidaris'' (Mortensen, 1932) ** Genus '' Lissocidaris'' (Mortensen, 1939) ** Genus '' Tretocidaris'' (Mortensen, 1903b) * Subfamily '' Goniocidarinae'' (Mortensen, 1928a) ** Genus '' Austrocidaris'' (H.L. Clark, 1907) ** Genus '' Goniocidaris'' (Desor, in Agassiz & Desor, 1846) ** Genus '' Ogmocidaris'' (Mortensen, 1921) ** Genus '' Psilocidaris'' (Mortensen, 1927) ** Genus '' Rhopalocidaris'' (Mortensen, 1927) ** Genus '' Schizocidaris'' (Mortensen, 1903b) ** Genus '' Adelcidaris'' (Cotton & Godfrey, 1942) (''nomen dubium'') * Tribe '' Phyllacanthina'' (Smith & Wright, 1989) ** Genus '' Phyllacanthus'' (Brandt, 1835) * Sub-family '' Stereocidarinae'' (Lambert, 1900) ** Genus '' Phalacrocidaris'' (Lambert, 1902) ** Genus ''

Stereocidaris ''Stereocidaris'' is a genus of echinoderm belonging to the family Cidaridae. The genus has almost cosmopolitan distribution. Species: *''Stereocidaris alcocki'' *''Stereocidaris baileyi'' *''Stereocidaris bolli'' *''Stereocidaris canalicu ...

'' (Pomel, 1883) * Subfamily '' Stylocidarinae'' (Mortensen, 1903) ** Genus ''

Acanthocidaris ''Acanthocidaris'' is a genus of echinoderms belonging to the family Cidaridae. The species of this genus are found in Australia, Indian Ocean and Malesia Malesia is a biogeographical region straddling the Equator and the boundaries of the ...

'' (Mortensen, 1903b) ** Genus ''

Plococidaris ''Plococidaris'' is a monotypic genus of echinoderms belonging to the family Cidaridae. The only species is ''Plococidaris verticillata''. The species is found in Malesia and Indian Ocean. References Cidaridae Cidaroida genera Monoty ...

'' (Mortensen, 1909) ** Genus '' Prionocidaris'' (A. Agassiz, 1863) ** Genus ''

Stylocidaris ''Stylocidaris'' is a genus of echinoderms belonging to the family Cidaridae. The genus has almost cosmopolitan distribution. Species Species: *''Stylocidaris affinis'' *''Stylocidaris albidens'' *''Stylocidaris amboinae'' *''Stylocidaris a ...

'' (Mortensen, 1909) A now abandoned genus, ''Cidarites'' was used in the late 18th and early 19th century to describe a number of species of both cidarid and echid sea urchins. Image:Eucidaris tribuloides (Slate-pencil Urchin).jpg, ''

Eucidaris tribuloides ''Eucidaris tribuloides'', the slate pencil urchin, is a species of cidaroid sea urchins that inhabits littoral regions of the Atlantic Ocean. As a member of the basal echinoid order Cidaroida, its morphological, developmental and molecular ge ...

''. Image:Phyllacanthus.jpg, '' Phyllacanthus imperialis'' Image:Plococidaris verticillata.jpg, ''

Plococidaris verticillata ''Plococidaris'' is a monotypic genus of echinoderms belonging to the family Cidaridae. The only species is ''Plococidaris verticillata''. The species is found in Malesia Malesia is a biogeographical region straddling the Equator and the ...

'' Image:Prionocidaris baculosa.jpg, ''

Prionocidaris baculosa ''Prionocidaris'' is a genus of echinoderms belonging to the family Cidaridae. The genus has almost cosmopolitan distribution. Species: *'' Prionocidaris anacachoensis'' *'' Prionocidaris australis'' *''Prionocidaris baculosa'' *'' Prionoc ...

'', from Philippines Image:Reef0228.jpg, ''

Chondrocidaris gigantea ''Chondrocidaris gigantea'' is a species of sea urchin of the family Cidaridae. Their armour is covered with spines. ''Chondrocidaris gigantea'' was first scientifically described in 1863 by Alexander Agassiz.Kroh, A. (2010). ''Chondrocidaris gi ...

'', from Hawaii Image:Stylocidaris affinis.jpg, '' Stylocidaris affinis'' Image:Cidaroid urchin in Galapagos.jpg, ''

Eucidaris galapagensis ''Eucidaris galapagensis,'' commonly referred to as the slate pencil sea urchin, is a species of echinoderms in the family of Cidaroid. This sea urchin lives in coastal areas in the Galapagos, Clipperton, and Cocos. The preferred substrate of ...

'' Image:Cidaris blakei.jpg, '' Cidaris blakei'' Image:Goniocidaris umbraculum (USNM E11208) 002.jpeg, '' Goniocidaris umbraculum''

References

The Echinoid Directory : Taxonomy; Natural History Museum, London

Description of the Cidaridae; Natural History Museum, London
* Hansson, H.G. (2001). Echinodermata, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50: pp. 336–351 {{Taxonbar, from=Q838992 Cisuralian first appearances Extant Permian first appearances Echinoderm families