An evaluation of zinc isotopes in historic shark enamel suggests megalodon and nice whites ate the identical meals, doubtlessly contributing to megalodon’s mysterious extinction
31 Could 2022
A prehistoric meals struggle could assist clarify the mysterious disappearance of megalodon, the world’s largest shark. It could have discovered itself in a dropping battle for prey with nice whites, suggests an evaluation of zinc in historic tooth enamel of each forms of shark.
It has been an estimated 3.5 million years because the final megalodon died, however the motive for the large carnivore’s demise stays a thriller. Earlier analysis suggests megalodon could have struggled to search out sufficient meals to fulfill their large urge for food, and Kenshu Shimada at DePaul College, Illinois, and his colleagues had been keen to search out out extra concerning the big fish’s place within the meals chain.
Megalodon’s roughly 15-metre-long physique contained a skeleton product of cartilage – which doesn’t fossilise effectively – so researchers are left with the animals’ palm-sized enamel for clues about the way it lived.
“My collaborators and I needed to see if we might decipher the weight-reduction plan of megalodon and different extinct sharks, together with the prehistoric nice white shark, utilizing zinc isotopes preserved in fossilised enamel,” says Shimada.
That is the primary time scientists have used zinc isotope evaluation on shark enamel, however the method “has been discovered to be a robust instrument to decipher the relative positions within the meals chain amongst various species”, says Shimada.
Utilizing a dental drill to gather tooth enamel, the workforce sampled 20 residing shark species and 13 extinct species together with megalodon. They then in contrast the various ranges of zinc trapped within the 262 particular person enamel. Zinc is crucial for animal life and is generally sourced from weight-reduction plan – with the precise steadiness of zinc isotopes within the weight-reduction plan, and therefore tooth enamel, indicative of the kind of meals an animal has eaten.
The researchers discovered that the zinc isotope ratio in megalodon’s pattern carefully matched that of historic nice white sharks. As a result of each species had low ranges of zinc of their tooth enamel, they in all probability shared the same apex predator place through the early Pliocene, about 5 million years in the past, when the 2 co-existed.
Shimada notes that earlier proof of fossilised chunk marks factors to the truth that nice whites and megalodon in all probability shared a weight-reduction plan of small whales, seals and sea lions. Whereas there could have been a number of causes for megalodon’s extinction, Shimada says he’s “very excited” to see that their examine affords extra proof that competitors for meals with nice whites was an element.
Journal reference: Nature Communications, DOI: 10.1038/s41467-022-30528-9
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