Smith, Andrew B. Department of Paleontology, Natural History Museum, London, United Kingdom.
Last reviewed:January 2021
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A former primitive order of brittle stars (class Ophiuroidea) reassigned to the order Ophiurida. The order Oegophiurida is an invalid taxon of brittle stars. Formerly comprising a single living genus, Ophiocanops, the members of this former order have been incorporated into the order Ophiurida. In the oegophiurid brittle stars, the gonads, together with outpouches of the digestive system (gastric ceca), extend from the central body cavity into the arms. This is a characteristic shared with asteroids (class Asteroidea). The digestive system is confined to the disk in all other ophiuroids, and the gonads extend into the arms in only a small number of primitive taxa. In addition, although paired and firmly united, the vertebral ossicles that make up the arms are not fused distally, whereas left and right vertebral ossicles are always fused in other extant ophiuroids. The oegophiurid brittle stars also primitively lack radial and oral shields in their disk, as well as lacking ventral arm plates. See also: Asteroidea; Echinodermata; Ophiuroidea
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