Ophiurida
| Ophiurida Temporal range: [1] | |
|---|---|
 | |
| Ophiura ophiura | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Ophiuroidea |
| Order: | Ophiurida Müller and Troschel, 1840 |
| Suborders | |
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See text. | |
The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars.
Characteristics
[edit]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.[2] 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.
Systematics and phylogeny
[edit]There is currently no consensus as to the subdivision of the Ophiurida. The order has been divided into the following suborders and infraorders [3]
Another classification scheme divides it into the following suborders:[4]
- Chilophiurina Matsumoto, 1915
- Laemophiurina Matsumoto, 1915
- Ophiothricidae Ljungman, 1867 (= Ophiotrichidae)
- Ophiurina Müller & Troschel, 1840
Another classification scheme divides it as:[5]
Ecology
[edit]Ophiurida have a world-wide distribution range and are found in oceans in different depths. Most of them are herbivores or detritus feeders.
References
[edit]- ↑ E.Clarkson, E.N.K. Clarkson, Invertebrate Palaeontology and Evolution. Wiley-Blackwell; 4.ed. (1998)
- ↑ R.C.Brusca, G.J.Brusca. Invertebrates. Sinauer Associates, 2 ed.(2003)
- ↑ 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.
- ↑ European Register of Marine Species
- ↑ "Mikko's Phylogeny Archive". Archived from the original on 2007-11-02. Retrieved 2008-01-09.
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- ↑ 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.