Ophiurida

Ophiurida
Temporal range: 469.4–0 Ma Middle Ordovician to Present
Ophiura ophiura
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Echinodermata
Class: Ophiuroidea
Superorder: Euryophiurida
Order: Ophiurida
Müller and Troschel, 1840
sensu O'Hara et al., 2017
Suborders
Synonyms
Ophiurae

Ophiurida is an order of echinoderms within the class Ophiuroidea. Ophiurida have a world-wide distribution range and are found in oceans in different depths. Most of them are herbivores or detritus feeders. The earliest fossil from this order (Protaster†) dates back to the Darriwilian in the Middle Ordovician.

Characteristics

Ophiurida have bursae for respiration and excretion, and dorsal and ventral arm shields are present and usually well developed. Arms are unbranched and incapable of coiling vertically. Most are five-armed, some with 4 or 6 arms as an abnormality, but others properly bear six or seven arms. The madreporite is on the oral surface. The digestive glands are entirely within the central disc. They move their arms side to side by means of ball-and-socket joints. Tropical species tend to contrast color from the environment, but most others prefer to blend in. These biochromes do not include echinochromes.

Taxonomy

The order has been divided into the suborders and infraorders by various taxonomists in the past. The latest accepted classification per O'Hara et al. (2017) is as follows:

There is also a suborder with 12 genera which is yet to be named.

The phylogenetic tree per O'Hara et al. (2017) is as follows.

Notes

  1. ↑ The genus is listed under Oegophiurida but has since been moved to Ophiurida.

References

  1. ↑ Protaster - The Paleobiology Database
  2. ↑ Stöhr S, O'Hara T, eds. (2026). "Protaster Forbes, 1849 †". World Ophiuroidea Database. World Register of Marine Species. Retrieved 12 November 2026.
  3. ↑ R.C.Brusca, G.J.Brusca. Invertebrates. Sinauer Associates, 2 ed.(2003)
  4. ↑ Thuy, Ben; Kutscher, Manfred; Płachno, Bartosz (2014). "A new brittle star from the Early Carboniferous of Poland and its implications on Paleozoic modern-type ophiuroid systematics". Acta Palaeontologica Polonica. doi:10.4202/app.00093.2014.
  5. ↑ Smith, A. B.; Paterson, G. L. J.; Lafay, B. (1995). "Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives". Zoological Journal of the Linnean Society. 114 (2): 213–243. doi:10.1006/zjls.1995.0024.
  6. ↑ European Register of Marine Species
  7. ↑ "Mikko's Phylogeny Archive". Archived from the original on 2007-11-02. Retrieved 2008-01-09.
  8. ↑ Stöhr S, O'Hara T, eds. (2026). "Ophiurida". World Ophiuroidea Database. World Register of Marine Species. Retrieved 3 November 2026.
  9. ↑ Stöhr S, O'Hara T, eds. (2026). "Ophiomusina". World Ophiuroidea Database. World Register of Marine Species. Retrieved 3 November 2026.
  10. ↑ Stöhr S, O'Hara T, eds. (2026). "Ophiurina". World Ophiuroidea Database. World Register of Marine Species. Retrieved 3 November 2026.
  11. ↑ Stöhr S, O'Hara T, eds. (2026). "Ophiurida incertae sedis". World Ophiuroidea Database. World Register of Marine Species. Retrieved 3 November 2026.
  12. ↑ O'Hara, Timothy D.; Stöhr, Sabine; Hugall, Andrew F.; Thuy, Ben; Martynov, Alexander (2018). "Morphological diagnoses of higher taxa in Ophiuroidea (Echinodermata) in support of a new classification". European Journal of Taxonomy (416). doi:10.5852/ejt.2018.416.