Mechanical optimalization of echinoid skeleton

PUBLICATION — Gehrmann T, Gorzelak P, Labisch S, Dirks J-H. 2026 Stress-correlated stereom organization in the echinoid tubercle reveals hierarchical mechanical integration. J. R. Soc. Interface 23: 20260592. https://doi.org/10.1098/rsif.2026.0592

Figure: A) Sea urchin Prionocidaris baculosa. B) Main load-bearing directions in the spine, determined using structural optimization. C) Stress distribution and regions important for load bearing, correlated with different microstructural types.

The secret behind the remarkable strength of the sea urchin test lies in its microarchitecture. By combining 3D imaging with computational simulations, we showed that the porous microstructure of the tubercle, i.e., the structure that transfers forces from the spine to the test, is precisely adapted to mechanical loading and closely matches the solutions predicted by structural optimization algorithms. This natural engineering strategy could inspire the design of next-generation lightweight, high-strength materials.