Cidaroida

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Cidaroida[1] 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

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Many different fossil Cidaroid radiola (MNHN).

According to World Register of Marine Species:[1]

References

Citations

  1. ^ a b Kroh, A.; Hansson, H. (2013). "Cidaroida". WoRMS. World Register of Marine Species. Retrieved 2013-12-31.

Sources

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Cidaroida: Brief Summary

provided by wikipedia EN

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.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN