Otodus megalodon, a megatooth shark that lived between 23 and 3.6 million years ago, was not a fast swimmer, but it had a mega-appetite explaining its gigantism, according to an analysis of the sharkâs placoid scales from the Late Miocene of Japan.
Otodus megalodon is commonly portrayed as a gigantic, monstrous shark in novels and films.
Although the species was indeed quite gigantic, the maximum possible length is thought to be about 15 m.
The animalâs biology was previously based largely on its gigantic teeth and vertebrae.
Inferred to be partially warm-blooded or regionally endothermic, the shark was traditionally assumed to be an active fast swimming shark.
However, the new study reveals that Otodus megalodonâs placoid scales are not equipped with narrowly-spaced ridges or âkeelsâ characteristic of fast-swimming sharks.
âOur big scientific findings come from âtiny evidenceâ as small as grains of sand,â said DePaul Universityâs Professor Kenshu Shimada.
In their study, Professor Shimada and colleagues examined placoid scales found in the rock matrix surrounding a previously described associated tooth set of Otodus megalodon from the Late Miocene of Japan.
âThis led my research team to consider Otodus megalodon to be an âaverage swimmerâ with occasional bursts of faster swimming for prey capture,â Professor Shimada said.
The new study also leads to a new paradox: although strong support for the presence of regional endothermy in Otodus megalodon exists based on a recent study, the question was how the fossil shark expended the high level of metabolic heat resulting from its warm-bloodedness without being an active swimmer.
Upon reviewing the literature, the authors noticed another possible function of endothermic body physiology that had been neglected in the biological context of Otodus megalodon â i.e., facilitating digestion as well as absorbing and processing nutrients.
âIt suddenly made perfect sense,â Professor…
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