Shark tooth fossils in sandstone matrix ... insights for identifying patterns in shark populations, such as which species coexisted, their feeding behaviors, and how these changed over time.

“Colloquially known as the ‘crow shark,’ Squalicorax was a ... making it all the more miraculous the tooth survived intact. The species met its demise during the Cretaceous-Tertiary ...

but with the "can-opener" shaped teeth of tiger sharks. The species met its demise during the Cretaceous-Tertiary extinction event (known as the KT extinction) that also wiped out the dinosaurs ...