Shark tooth analysis reveals 20-million-year lineage of apex predators

A comprehensive study of fossil shark teeth from the Miocene of Maryland has traced a 20-million-year lineage of macro-predatory sharks. By analyzing tooth shape, serration patterns, and isotopic signatures, researchers identified a previously unrecognized transitional form between the extinct Otodus and modern great white sharks. The study also used zinc isotopes to reconstruct dietary patterns, confirming that these sharks were apex predators that hunted marine mammals. The findings help resolve long-standing debates about the evolutionary origins of the modern white shark lineage.