X-RAY VISUALIZATION AS IDENTIFICATION TECHNIQUE FOR FRAGMENTS OF DEEP-SEA HABITAT-FORMING SCLERACTINIANS

Abstract

Deep-sea colonial Scleractinia (Anthozoa: Hexacorallia) are indicator species of vulnerable marine ecosystems known as deep-sea coral reefs. The number of species of deep-sea community-forming colonial Scleractinia is small and specimens of good preservation, especially those collected in a live state, can be easily identified to the species level. Identification of fragments, especially those of the basal part of colonies, can be difficult. We have shown that X-ray examination can effectively distinguish colony fragments of the widespread deep-sea community-forming scleractinian corals Desmophyllum pertusum and Solenosmilia variabilis (Caryophylliidae). The skeleton of S. variabilis is considerably denser and less X-ray permeable compared to D. pertusum. The calyx cavities of the corallites of S. variabilis are visible only at the periphery of the fragment and practically do not extend to the outside. In D. pertusum, the cavities of the corallites can be deeply traced in the fragment body, they have a conical shape and considerably expand to the periphery. The proposed method of identification is inexpensive, does not require special sample preparation, and allows rapid identification of bulk material.