Cidaroida
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Cidaroida, also known as pencil urchins, 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
Their primary spines are much more widely separated than in other sea urchins, and they have no buccal slits. Other primitive features include relatively simple plates in the test, and the ambulacral plates continuing as a series across the membrane that surrounds the mouth.
Families
According to World Register of Marine Species:
- family AnisocidaridaeVadet, 1999 †
- superfamily CidaroideaGray, 1825 family CidaridaeGray, 1825 family CtenocidaridaeMortensen, 1928a family PaurocidaridaeVadet, 1999a †
- family DiplocidaridaeGregory, 1900 †
- family HeterocidaridaeMortensen, 1934 †
- superfamily HistocidaroideaLambert, 1900 family HistocidaridaeLambert, 1900 family PsychocidaridaeIkeda, 1936
- family MiocidaridaeDurham & Melville, 1957 †
- family PolycidaridaeVadet, 1988 †
- family RhabdocidaridaeLambert, 1900 †
- family SerpianotiaridaeHagdorn, 1995 †
- family TriadocidaridaeSmith, 1994c †
- Stylocidaris affinis (Cidaridae)
- Notocidaris sp. (Ctenocidaridae)
- Histocidaris variabilis (Histocidaridae)
- Tylocidaris ohshimai (Psychocidaridae)
- Miocidaris coaeva (Miocidaridae, fossil)
- Paracidaris florigemma (Polycidaridae, fossil)
- Cidaris blakei, abyssal Caribbean species
- Eucidaris tribuloides, shallow Caribbean species
- Phyllacanthus imperialis, shallow Indo-Pacific species
- Plococidaris verticillata, rare shallow Indo-Pacific species
- Prionocidaris baculosa, from Philippines
- Chondrocidaris gigantea, from Hawaii
Citations
Sources
- : ()
- Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 980. ISBN 0-03-056747-5.
- National History Museum. .