UC Riverside

Due to increasing predatory pressure over hundreds of millions of years, gastropods have evolved hard calcified shells with novel microstructures to increase the toughness of their shells and to protect their soft body. Initially, prismatic forms of these shells were dominant, which evolved to layered nacre-like structures. However, during the Mesozoic marine revolution (~250MYa) this arms race between gastropods and durophagus predators, yielded the evolutionary newest shell structure, the crossed lamellar microstructure. This structure arose as the dominant shell architecture found in the majority of the 60,000 extant specimens of gastropods. The primary advantage of this structure was that it enabled toughening, four orders of magnitude greater than the mineral from which it is constructed, calcium carbonate. The crossed lamellar structure also allowed for the diversification of shell morphologies, resulting in a range of adaptations to further the success of gastropods in many different ecological niches. A very recent anti-predation adaption (<50MYa) that has occurred in the gastropod Hinea brasiliana is the ability to bioluminesce and diffuse the produced light over the surface of their shell. We investigated the ultrastructure and optical properties of the shell of H.brasiliana and to uncover the structural origins of the optical diffusion and found H.brasiliana shell to be typical for caenogastropoda. The diffusion of light in the shells of numerous other non-luminescent gastropods were studied, in which pigmentation is In addition we investigated the anisotropy in the indentation fracture properties of the crossed lamellar structure using nanoindentation. We used these design cues obtained to develop multifunctional fiber-reinforced composites with tunable mechanical and optical properties.