How does the armored tiling on shark and ray cartilage maintain a continuous covering as the animals’ skeletons expand during growth?

This is a question that has perplexed Professor Mason Dean, a marine biologist in the Department of Infectious Diseases and Public Health at City University of Hong Kong (CityUHK) since he was in graduate school.

An expert in skeletal development, structure and function in vertebrate animals, but with a particular focus on (and affection for) sharks and rays, Professor Dean says he was curious about how nature keeps complex surfaces covered while organs and animals are growing, and their surfaces are changing.