ABSTRACT
Using a research submersible, swimming behavior was discovered in 4 bathyal Bahamian-Caribbean ophiuroids: Ophiuroconis miliaria, Ophiothrix sp., Ophiocirce antillarum and Ophiernus adspersus. The skeletal ossicles of swimming ophiuroids are thinner and more porous than non-swimmers’ ossicles, and swimmers’ intervertebral articulations increase arm flexibility and the attachment surface for muscle tissue. The feather-spines of O. adspersus, described for the first time, are homologous to accessory arm spines of the mid-Jurassic Ophiopinna elegans, which is suggested to be a swimming ophioleucid. Accessory spines of Ophioleucidae are suggested to aid in swimming.
