The skeletal structure of Desmophyllum cristagalli: the use of deep‐water corals in sclerochronology

Skeletal banding has been found in the deep‐water scleractinian coral Desmophyllum cristagalli, an important animal in studies of climate change. This banding pattern sheds light on skeletogenesis and suggests methods by which the record of climate change contained within the coral skeletons may be interpreted. A central wall built of trabeculae forms the interior of the septa and rings the theca. Lamellae form a sheath over the trabecular frame, showing continuity from thecal edge to septum. Skeletal bands are added by the tissue layer, which overlaps and seals the internal coral and upper portion of the outer theca. Truncated inner bands on the outer theca indicate a pattern of skeletal deposition and dissolution dependent on the presence or absence of the live tissue layer. A long‐term record will be difficult to collect from D. cristagalli since lamellae are less than 10 μm thick and band position is unpredictable. Density banding in shallow‐water coral skeletons has long been recognized as a valuable paleo‐oceanographic tool, and deep‐water corals are now being used to reconstruct deep‐ocean environments. Pattern of skeletal growth must be carefully considered if deep‐water corals are to be used as proxy climate recorders.