Invertebrates Are Heavy Metal: An Overview of Armor, Weapons, and Other Cuticular Adaptations of Diverse Lineages

Studies of invertebrate cuticle are diverse, encompassing many different structures from a range of distantly related lineages. The purpose of this chapter is to provide a general overview of the mechanisms by which metals augment cuticle among the major animal phyla, ranging from biomineralization of calcium-enriched skeletons of sponges (Porifera) to the increased hardness of the snail radula due to the presence of metal-ligand coordinated bonds. Several examples are provided that showcase the range of uses of metal-enriched cuticle. The chapter concludes with statements of potential future directions of the research, including thorough studies to develop a clearer understanding of the mechanism for enriching cuticle with metal-ligand coordinated bonds.