Composition, ultrastructure, and material properties of California spiny lobster (Panulirus interruptus) exoskeleton

We examined five exoskeletal structures in the California spiny lobster, Panulirus interruptus, to better understand both the extent of exoskeleton variation within a single crustacean species and the relationship between morphology and function. The five structures were the carapace, antenna, rostral horn, mandible, and abdominal segment, each of which provides predator defenses to different degrees, potentially leading to differentiation in structure construction. Here, we characterized and compared the mineralization (wt. % and concentration of Ca and Mg), ultrastructure (cuticle layer thickness), and mechanical properties (hardness and stiffness). Layer thickness (µm) and wt. % mineralization were determined using a scanning electron microscope (SEM) equipped with electron-dispersive x-ray spectroscopy (EDX). Concentration of elements (µmol/mg sample) was measured using inductively-coupled x-ray spectrometry (ICP-MS), while material properties (GPa) were measured using a nanoindenter with a Berkovitch diamond tip.