Cartilaginous fish skeletal tissues

We learn in introductory biology classes that cartilaginous fishes (sharks, rays and chimaera) have skeletons of cartilage, not bone. Growing evidence, however, suggests the answer is not so simple, that the skeletal tissues of these fishes are more diverse, active and variable than previously believed. In this chapter, we assemble current knowledge on skeletal tissue types in sharks and rays, describing the two tissue types classically thought to define this group—tessellated cartilage and areolar cartilage—but also the evidence for additional, less-appreciated tissues that likely have important functional properties in the skeleton. The collected picture of shark and ray skeletal biology offers a roadmap for future work, exploring physiological aspects of these tissues and how they respond to meet the animals’ performance and ecological needs. © 2024 Elsevier Inc. All rights reserved.