Macrostructural anatomy of sea cucumber’s calcareous rings

Despite descending from heavily calcified ancestors, the holothuroid skeleton is fully internal and composed of microscopic ossicles and a ring of plates bound by connective tissue, the calcareous ring. The calcareous ring exhibits a complex and poorly understood morphology; as a result, establishing unambiguous homology statements about its macrostructure has been challenging and phylogenetic studies have had to simplify this important structure. The aim of this project is to investigate the 3D anatomy of the calcareous ring under μCT and the relationship between the calcareous ring and its associated organs.