In this shark tale for Save our Seas Foundation, Erin Dillon explains the characteristics of some of the shark scales found on four well-known shark species. Erin is pioneering a new technique that uses these scales, known as dermal denticles, found in modern reefs and the fossil record to study changes in shark abundance and community composition over time.

Erin carries a bulk bag of a fossil reef sediment from Cañon del Buho in the Dominican Republic on March 17, 2016. The ten-kilogram bag may hold some 25 tiny shark scales known as dermal denticles.