Dissertation Research: A Cladistic Analysis of the Deep Sea Ophiuroid Genera Ophiomusium Lyman and Ophiosphalma H.L. Clark and Their Relations Within Ophiolepididae ......

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9701264 LIPSCOMB Ophiuroids, or brittle stars, are the largest class of echinoderms. They occupy nearly every marine environment from the tropics to polar seas, and the intertidal to abyssal zones. Nonetheless, ophiuroids remain one of the least studied groups with respect to their systematics. Brittle stars in the deep sea may also inform an ongoing debate about the origins of deep-sea animals. Some scientists believe that the deep-sea environment is a refuge for ancient species, others believe that deep-water species appeared more recently, by invasions from shallow-water and Antarctic faunas. In this research, Diana Lipscomb, David Pawson and doctoral candidate Susan Hottenrott will conduct a systematic revision of two ophuroid genera, Ophiomusium and Ophiosphalma (family Ophiolepididae) which are dominant members of the deep-sea fauna in all oceans. The 77 species that comprise these genera are poorly characterized. By studying the gross and fine structural anatomy of specimens archived at various museums, this study will provide the first detailed description and identification keys of these species. It is anticipated that this analysis will result in a better understanding of ophuroids in general and deep-sea species in particular. The study should also give insights into the origin of deep sea faunas, by including biogeographic analyses that will test competing hypotheses for the origins of these brittle stars.