Otodus megalodon hunting whale Cethoterium. Credit: Hugo Salais, Metazoa Studio
An advanced work by University of Bristol Researchers have found that the evolution of the teeth of the prehistoric giant shark Megalodon and its relatives is a product of being a giant instead of adapting to new eating habits.
The iconic Megalodon was the largest shark ever to roam the seas. The name translates as ‘big teeth’ and refers to the massive teeth that represent the most common fossils of the species. They are broad and triangular, unlike the crooked, knife-like teeth of Megalodon’s closest relatives.
The differences in tooth shape seen in this group of giant sharks are traditionally thought to reflect a change in diet. While the earliest relatives probably used their teeth to pierce small and fast-moving predators such as fish, Megalodon most likely used them to bite large pieces of meat from marine mammals or to break such prey with strong lateral head blows.
In a new study published in the journal today Scientific Reports, Scientists have used computational tools to understand how these megatooth shark teeth work during feeding.
Finite element models of megatooth shark teeth. Model stress describes a measure of how structures are affected by forces. Warm colors indicate high stress and cold colors indicate low stress. Credit: Antonio Ballell and Humberto Ferrón
Antonio Ballell, a doctoral student at the University of Bristol School of Earth Sciences, said: “We have applied engineering techniques to digitally simulate how different tooth shapes control the biting forces and loads that result from lateral head movements.
“This method, called finite element analysis, has previously been used to understand how resistant different biological structures are under special forces.
“We expected that the teeth of the megalodon could resist forces better than the teeth of their larger and smaller relatives. Surprisingly, we restored the opposite when removing the tooth size from the simulations: Megalodon teeth are weaker than the most delicate teeth of other megatooth sharks. ”
Dr. Humberto Ferrón, a postdoctoral researcher and co-author of the study, said: “Our findings seem to contradict the traditional functional interpretations of the teeth of this giant shark group. We think that other biological processes may be responsible for the evolutionary change in the teeth.
“For example, changes in tooth shape that occur in newer, larger forms, such as Megalodon, from older, smaller species, are very similar to those observed during Megalodon growth.
“That is, juvenile Megalodon individuals have teeth that resemble the teeth of an adult megatooth shark. Thus, instead of specializing in nutrition, we believe that the acquisition of a giant body size is responsible for the evolution of Megalodon’s unique teeth. ”
Reference: “Biomechanical concepts of Megatooth shark teeth (Lamniformes: Otodontidae)” by A. Ballell and HG Ferrón, 13 January 2021, Scientific Reports.