The transition in zinc distribution from Otodus obliquus to Otodus megalodon teeth reveals the dietary evolution of an apex predator.
For much of the Cenozoic, sharks of the genus Otodus were the apex predators of coastal seas. From the Paleocene species Otodus obliquus to the famous Pliocene Otodus megalodon, members of this lineage were gigantic predators. During their evolution, their teeth also changed dramatically. Early species had relatively slender teeth with distinct lateral cusplets and smooth cutting edges, making them better suited for gripping and piercing prey. They were therefore likely to have fed mainly on fishes.
By the Eocene, marine mammals such as cetaceans and sirenians had appeared and began to diversify. Around the same time, Otodus teeth also evolved toward a form better suited for slicing large prey. The crowns became broader, serrations developed along the cutting edges, and the lateral cusplets became reduced or disappeared. These changes ultimately produced the enormous serrated teeth of Otodus megalodon, allowing it to prey on large marine mammals.
Although the evolution of Otodus tooth morphology has been extensively studied, it remains unclear whether their teeth also underwent more subtle adaptations beyond changes in shape. To investigate this question, researchers have begun examining the chemical composition of these teeth.
Want to read more?
Subscribe to thesoundofevolution.com to keep reading this exclusive post.
