LOCKHART, S. J.; MOOI, R.; PEARSE, J. S.; California Academy of Sciences, San Francisco and University of California, Santa Cruz; California Academy of Sciences, San Francisco; University of California, Santa Cruz: Does the brooding cidaroid, Aporocidaris milleri (Agassiz 1898), really have the greatest geographic range of any regular sea urchin?

When Fell (1976) and David et al. (in press) synonymized Aporocidaris fragilis Agassiz & H.L. Clark 1907, (Alaska) and A. antarctica Mortensen 1909, (Antarctica) with A. milleri (Agassiz 1898) (equatorial eastern Pacific), the latter species arguably became the regular echinoid with the greatest known geographic range, certainly in terms of latitude. This is a remarkable feat for a species that brood-protects its young and apparently lacks a dispersive larval stage. Participation on the ANtarctic benthic DEEP-sea biodiversity (ANDEEP) expedition of the RV �Polarstern� ANT XIX-3 has provided new material that allows elucidation of the key problems leading to the confusion surrounding these species. A much-needed review of the genus Aporocidaris Agassiz & H.L. Clark 1907 is provided here using morphological and, where attainable, molecular data. In order to avoid further misidentifications, each species is described and figured, and a key is provided. Revised biogeographical data, based only on specimens examined and identified by us, yields the first accurate geographic ranges of Aporocidaris species. When correlated with gene flow estimates, these results will lead to a better understanding of the relationship between biogeography and reproductive strategy. A morphology-based phylogeny of the genus is also presented.