CT scans and visualization tools are now allowing scientists to recreate the weird cartilaginous structures of ancient predators.
An illustration of the ancient shark Edestus heinrichi preying on a fish. Many ancient sharks had different jaws than modern sharks.
A restoration of what the whorl-tooth ratfish Helicoprion looked like by artist Gary Staab.
Taken together, all these “saws, scissors and sharks” would seem to suggest that cartilaginous fish of more than 250 million years ago were far stranger than anything alive today. No living equivalents of Edestus or Ferromirum exist. But familiarity often results in indifference.
Both Edestus and Helicoprion, Tapanila points out, evolved to cut through soft prey with teeth arranged along the midline of the jaw. This kind of biting strategy made sense when the seas were full of fossil squid and cuttlefish relatives—the way the jaws of Helicoprion work might have even effectively shucked the soft parts of ammonites from their coiled shells. But this type of biting didn’t persist. “One thing we see in both Edestus and Helicoprion is that they both appear to be deadends to their respective lineages,” Tapanila says, and the same type of predators never evolved again. These hunters were specialized, and they were very good at what they did. In the same deposits that paleontologists find Edestus jaws, for example, experts sometimes find fish tails that were lopped off the body, possible remnants of Edestus meals.
More:
https://www.smithsonianmag.com/science-nature/new-technologies-reveal-strange-jaws-prehistoric-sharks-180977396/
