List of echinoderm orders

A brittle star, Ophionereis reticulata
A sea cucumber from Malaysia
Starfish exhibit a wide range of colours

This List of echinoderm orders concerns the various classes and orders into which taxonomists categorize the roughly 7000 extant species[1] as well as the extinct species of the exclusively marine phylum Echinodermata.

Subphylum Crinozoa

Class Crinoidea

Crinoid


Haeckel Cystoidea

Class Paracrinoidea †

No orders, 13 to 15 genera are known.

Class Cystoidea †

  • order Aristocystitida †
  • order Asteroblastida †
  • order Glyptosphaeritida †
  • order Sphaeronitida †

Class Edrioasteroidea †

Streptaster vorticellatus (Edrioasteroidea)

Subphylum Asterozoa

Class Ophiuroidea (Brittle stars)

    • Order Euryalida
    • Order Ophiurida
    • Order Amphilepidida
    • Order Ophiacanthida
    • Order Ophioleucida
    • Order Ophioscolecida

Class Asteroidea (Starfish)

Subphylum Echinozoa

Class Echinoidea (Sea urchins)

Strongylocentrotus purpuratus, a well-armoured sea urchin

Class Holothuroidea (Sea cucumbers)

Class Ophiocistioidea †

Ophiocystioidea

No orders recognized: class is divided up into four families, Eucladiidae, Sollasiniidae, Volchoviidae, and Rhenosquamidae. The inclusion of Rhenosquamidae within Ophiocistioidea is doubtful, as the organs identified in fossils of Rhenosquamus as the characteristic "scaly podia" otherwise diagnostic of ophiocistioids may not, in fact, be such structures.

Class Helioplacoidea †

No known orders, 2 known species, Helicoplacus curtisi and H. guthi

Subphylum Blastozoa †

Class Blastoidea †

Blastoidea
  • Ordre Coronata †
  • Order Fissiculata †
  • Order Spiraculata †
  • basal Macurdablastus †

Class Eocrinoidea †

Gogia spiralis (Eocrinoidea)
  • Order Ascocystida †
  • Order Gogiida †
  • Order Imbricata †
  • Order Trachelocrinida †

Subphylum Homostelea / Homalozoa †

Corthurnocystis, a Stylophora.

Class Ctenocystoidea †

    • order Ctenocystida †

Class Homoiostelea †

Class Homostelea †

    • order Cincta †

= Class Stylophora †

    • order Cornuta †
    • order Mitrata †

References

  1. ↑ "Animal Diversity Web - Echinodermata". University of Michigan Museum of Zoology. Retrieved 26 August 2012.
  2. ↑ Sweet, Elizabeth (2005-11-22). "Asterozoa: Fossil groups: SciComms 05-06: Earth Sciences". University of Bristol. Retrieved 2008-05-07.
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