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Ophiuroidea Modern Forms

Modern brittle star
Ophiuroids have changed very little over a 500 million period. The same body shapes and forms are still seen today,although there is greater diversification at a lower taxonomic level (at genus and species level). There are over 250 genera of ophiuroids described with more than 2000 species. Ophiuroidea are very abundant in modern oceans in a range of environments. They span the seas from the poles to the tropics at various depths. They are found in huge numbers at bathyal (continental shelf) and abyssal (deepest seas up to 2000m) depths, but are also found in inter-tidal areas.  They are generally confined to normal saline conditions but a group of very adventurous brittle stars are now quite content living in brackish estuarine waters, this is unique among the echinoderms .

They have various feeding strategies which has allowed divergence of the species:

Basket star image showing the many branching arms

Ophiuroids have developed many defences against predation:

Red brittle star

Author: Lorna O'Brien
Last updated: 19/11/2006
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All images have be reproduced with the permission of the Southeastern Regional Taxonomic Center/South Carolina Department of Natural Resources

Websites produced by students on the MSc Palaeobiology programme in the Department of Earth Sciences at the University of Bristol for academic year 2006-7