According to new research published in the Journal of Life and Environmental Sciences, megalodon sharks likely went extinct at least one million years earlier than previously thought and direct competition with great whites might be to blame.
A team of researchers led by vertebrate paleontologist Robert Boessenecker from the College of Charleston-South Carolina, analyzed fossil occurrence of megalodon teeth found in densely sampled rock of California and Baja California (Mexico). Through their examination, they found that genuine fossil occurrences were present only until the end of the early Pliocene epoch, 3.6 million years ago.
“We used the same worldwide dataset as earlier researchers but thoroughly vetted every fossil occurrence, and found that most of the dates had several problems-fossils with dates too young or imprecise, fossils that have been misidentified, or old dates that have since been refined by improvements in geology; and we now know the specimens are much younger,” Sarah Boessenecker, from the University of Leicester-United Kingdom said.
“After making extensive adjustments to this worldwide sample and statistically re-analyzing the data, we found that the extinction of O. megalodon must have happened at least one million years earlier than previously determined.”
Their findings contradict other theories, including that megalodon was part of a mass extinction that occurred during a bombardment of solar radiation nearly 2.6 million years ago and well before the disappearance of numerous species of seals, walruses, sea cows, porpoises, dolphins and whales about 1 to 2.5 million years ago.
“It is possible that there was a period of faunal turnover (many species becoming extinct and many new species appearing) rather than a true immediate and catastrophic extinction caused by an astronomical cataclysm like a supernova,” Boessenecker said.
A more likely scenario is that the emergence of the modern great white shark (Carcharodon carcharias)contributed to the possibly warm-blooded megalodon’s extinction. Great whites, which would have been megalodon’s direct competition for its primary food sources, first show up with serrated teeth about 6 million years ago and only in the Pacific; by 4 million years ago, they are finally found worldwide.
“We propose that this short overlap (3.6-4 million years ago) was sufficient time for great white sharks to spread worldwide and outcompete O. megalodon throughout its range, driving it to extinction-rather than radiation from outer space,” Boessenecker said.
https://www.sharkophile.com/2019/01/01/sharkofiles-megalodon/