Historic megalodon sharks might have been no less than 2 metres lengthy at start – they usually may need grown so massive by consuming unhatched eggs within the uterus.
Kenshu Shimada at DePaul College in Chicago and his colleagues examined an Otodusmegalodon fossil that was recovered within the 1860s from 15-million-year-old rock and is now housed on the Royal Belgian Institute of Pure Sciences. Finding out the shark’s vertebrae, allowed them to estimate its physique dimension at numerous levels in its life.
“Megalodon’s dimension at start was about 2 metres in whole, which signifies that it should have given reside start like all present-day lamniform sharks do,” says Shimada.
Just like how a tree trunk has annual progress rings, the shark vertebrae has progress bands. By counting these, Shimada and his group recommend that this megalodon specimen died at 46 years outdated.
Earlier research into O.megalodon have relied on proof from its enamel to estimate physique dimension. It is because enamel are sometimes the one a part of a shark to fossilise, as its skeleton is manufactured from cartilage and never bone. Finding out uncommon vertebral stays is important to studying extra about historical sharks, says Jack Cooper at Swansea College, UK.
The massive start dimension of O. megalodon means that the younger sharks, like many present-day sharks, ate unhatched eggs within the uterus to outlive – a phenomenon known as intrauterine cannibalism.
“The consequence is that only some pups will survive and develop, however every of them can turn out to be massive in physique dimension at start which supplies [them] a bonus as already massive predators,” says Shimada.
Whereas the brand new analysis has supplied info on the expansion sample between start and center age, we nonetheless know little about megalodon progress later in life.
Journal reference: Historic Biology, DOI: 10.1080/08912963.2020.1861608
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