3D-Xray-tomography of American lobster shell-structure. An overview

A total inventory of density defined objects of American lobster cuticle was obtained by using high resolution 3D Xray tomography, micro-computed-tomography. Through this relatively unbiased sampling approach several new objects were discovered in intermolt cuticle of the lobster carapace. Using free and open-source software the outlines of density-defined objects were obtained and their locations in 3D space calculated allowing population parameters about these objects to be determined. Nearest neighbor distances between objects allowed interpretations of structural relationships of and between objects. Several organule types are recognized by their structural outlines and density signatures. A hierarchy of organule types and distribution suggests they develop during sequential molts. New objects (stalactites, Bouligand spirals, and basal granules) are described as mineral structures with well defined morphological character, allowing them to be recognized by their descriptive names and distributions. The three new cuticular objects appear to represent forms of calcium carbonate deposition in the sequential layers of exocuticle, endocuticle and membranous layer and may provide signatures of underlying epidermal cells.