Structural design of the minute clypeasteroid echinoid Echinocyamus pusillus

The clypeasteroid echinoid skeleton is a multi-plated, light-weight shell construction produced by biomineralization processes. In shell constructions, joints between individual elements are considered as weak points, yet, these echinoid skeleton shows an extensive preservation potential in both Recent and fossil environments. The remarkable strength of the test is achieved by skeletal reinforcement structures and their constructional layouts. Micro-computed tomography and scanning electron microscopy are used for micro-structural and volumetric analyses of the echinoid’s skeleton. It is shown, that strengthening mechanisms act on different hierarchical levels from the overall shape of the skeleton to micro-skeletal interlocking. The tight-fitting and interlocking plate joints lead to a shell considered to behave as a monolithic structure. The plate’s architecture features distinct regions interpreted as a significant load transferring system. The internal support system follows the seg...