The occurrence of corallimorpharians (naked corals) Daphne G. Fautin Department of Ecology and Evolutionary Biology and Natural History Museum University of Kansas Lawrence, Kansas 66045, USA John M. Guinotte Marine Conservation Biology Institute th Ave NE, Suite B-300 Bellevue, Washington 98004, USA

CORALLIMORPHARIA

DIVERSITY 1631 valid species of Scleractinia 55 valid species of Corallimorpharia 1112 valid species of Actiniaria Members of all taxa occur throughout the world’s oceans

PHYLOGENETIC RELATIONSHIPS

to compare the depth distribution of deep-sea corallimorpharians with that of deep-sea scleractinians OBJECTIVE to infer if CaCO 3 concentration may be relevant to the occurrence of these animals that are so similar except for the skeleton

DATA: general surveys rather than those for the target organisms

and US Antarctic Program The Challenger Expedition

Challenger Scleractinia Corallimorpharia Species98 (91 to species) 3 (in 41 genera)(All Corallimorphus) Stations706 (Both occurred at 3 stations) Depth range m m Average depth1439 m3142 m p = t-test 1-tailed, unequal variance

Antarctic Scleractinia Corallimorpharia Species38 (37 to species) 2 (in 19 genera)(Both Corallimorphus) Stations19012 (Both occurred at 8 stations) Depth range m m Average depth676 m1600 m p = t-test 1-tailed, unequal variance

COMPARISONS between Antarctic and Challenger data Antarctic lower diversity in both taxa Twice as many stations in Antarctic Average Antarctic depth about half that of Challenger for both taxa In Antarctica, depth range of Scleractinia slightly shallower, that of Corallimorpharia considerably shallower and deeper Yet average depth of corallimorpharians significantly deeper in both datasets

CaCO 3 concentration: proportion deeper than aragonite saturation horizon (1995) ScleractiniaCorallimorpharia Challenger stations 18/40 (45%)5/5 (100%) species 19/98 (19%)3/3 (100%) (in 10/41 genera) Antarctic stations 29/122 (24%) 5/10 (50%) species 16/38 (42%)2/2 (100%) (in 9/19 genera)

IMPLICATIONS Fine and Tchernov Science. Scleractinian coral species survive and recover from decalcification. These “naked” polyps are indistinguishable from corallimorpharians “Polyp bail-out”: under stress (including in aquaria), scleractinians can crawl out of their skeletons.

IMPLICATIONS

THE FUTURE?? and/or Shallower scleractinians More corallimorpharian species

ACKNOWLEDGMENTS Funding was provided by US National Science Foundation grants DEB and DEB (in the program PEET - Partnerships to Enhance Expertise in Taxonomy), grant OCE , and grant EF (in the program Assembling the Tree of Life). Sukeerthi Bokka for assembling data Matthew Jones for photo of corallimorpharian James C Orr for CaCO 3 concentration data