Research Reveals Surprises in Evolution of Megalodon Teeth

The megalodon’s legendary big teeth — for which it’s named — likely came as a result of its gargantuan size rather than its changing dietary preferences as previously believed.

Model of megalodon shark jaws at the American Museum of Natural History, in New York. (By Spotty11222 at English Wikipedia)

(CN) — Revered among the fiercest predators ever to grace the seven seas, megalodon — the iconic “big tooth” shark — surprisingly possessed weaker teeth than its smaller descendants, according to new research.

Megalodon had broad, triangular teeth which looked and behaved nothing like the curved, blade-like teeth of its closest relatives. Researchers noted a widening of crowns, loss of lateral cusplets and — most frighteningly — the acquisition of serrated cutting edges in the teeth of these fearsome creatures. The changes in its dentition demonstrate an evolution from puncturing-tearing to cutting behavior, allowing megalodon to hunt larger prey as it grew in size.

The changes in megalodon’s bite allowed it to transition from hunting small, elusive prey like fish to tearing hunks of flesh from the backs of large marine mammals like whales, according to a study published Wednesday in the journal Scientific Reports.

Weighing in at more than 50 tons and growing to over 45 feet long, megalodon was the largest shark ever known to exist. Only a single nearly complete megalodon skeleton has ever been recovered, so most of what scientists know comes from fossilized teeth. It could bite into prey and shake its head side-to-side to rip flesh straight from bone.

Thanks to advances in computational tools, researchers were able to employ von Mises stress distribution patterns to simulate the bite force produced by the various tooth shapes discovered over the years.

“We applied engineering techniques to digitally simulate how different tooth shapes handled bite forces and loads resulting from lateral head movements,” said Antonio Ballell, doctoral student at the University of Bristol School of Earth Sciences, in a related statement. “This method, called Finite Element Analysis, has been previously used to understand how resistant different biological structures are under specific forces.

“We expected to find that megalodon teeth could resist forces better than those of its older and smaller relatives. Surprisingly, when we removed tooth size from the simulations, we recovered the opposite pattern: Megalodon teeth are relatively weaker than the most gracile teeth of other megatooth sharks.”

The team found that the region of the shark’s tooth placed under the highest stress during a bite was located near the tip of the main crown, where the puncture force is applied, while the lowest stress levels occurred near the base. Lateral and posterior teeth felt the highest stress because megalodon’s jaws act like levers which increase the surrounding bite force, while these teeth also have less surface area to distribute the load.

According to Humberto Ferrón, post-doctoral researcher at the University of Bristol and co-author of the study, juvenile megalodons have teeth resembling those of older megatooth sharks, which led researchers to believe that their subsequent growth caused the dramatic change in tooth shape and function.

“Our results might seem to be at odds with traditional functional interpretations of the dentitions of these group of giant sharks, Ferrón explained in a related statement. “We think that other biological processes might be responsible for the evolutionary change in their dentitions.

He said changes in tooth shape that occurred between older species and the megalodon appeared as the megalodon grew.

“That is, juvenile megalodon individuals have teeth that resemble those of older megatooth sharks,” Ferrón said. “Thus, instead of feeding specialization, we think that the acquisition of its gigantic body size was responsible for the evolution of the peculiar teeth of megalodon.”

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