Microstructure and mechanical design in the lantern ossicles of the regular sea‐urchinParacentrotus lividusiA scanning electron microscope study

Abstract

Abstract Echinoids are the echinoderm group which has explored and exploited most efficiently the potential of the endoskeleton in a range of extremely advanced and sophisticated adaptive solutions. The most ingenious of these adaptations are employed in the dental apparatus, whose different elements represent a striking example of the versatility of the skeletal tissue. The dental ossicles (jaws, rotulae, compasses and teeth), though having the same basic organization, show a wide range of structural and functional solutions: inorganic phase and organic stroma are variously combined and integrated in a very plastic and adaptable tissue, which is able to fulfil very specific mechanical requirements. On the whole, all the different arrangements shown by the dental elements can be considered as differentiations of the two limit‐models of skeletal microarchitecture, represented respectively by classical porous stereom and a composite lamellar structure. The first structural model is by far the most common: a...