Until now, the estimated date of extinction of the gigantic prehistoric shark known as megalodon – “big tooth” – was around 2.6 million years ago. However, a team of researchers led by vertebrate paleontologist Robert Boessenecker, from the College of Charleston (South Carolina, USA), estimates that the correct date is one million years earlier, 3.6 years ago. millions.
Paleontologists are able to narrow the date of extinction of the megalodon based on the fossil remains that have been found of it – mainly teeth and some vertebrae – but the new research, published in the scientific journal PeerJ , indicates that there are many doubts about the data referring to the exact location of the discovery of some of the fossils that have been used to establish the date of extinction of the giant shark.
Boessenecker and his research colleagues have reviewed all the megalodon fossil discoveries recorded in California and Baja California, Mexico, and have concluded that genuine finds are only those that are more than 3.6 million years old. antiquity , that is, those that were present until the beginning of the Middle Pliocene. All subsequent fossils present little information about where they were found and, according to the study authors, are likely to come from other fossil sites or show evidence of erosion from older deposits.
“We used the same global data set as previous researchers, but we thoroughly examined each fossil find and found that most had several problems: too imprecise dates, misidentified fossils …” explains Boessenecker. After making extensive adjustments to this world sample and statistically re-analyzing the data, we discovered that the extinction of the megalodon must have occurred a million years earlier than previously determined. “
The cause of its extinction is unclear
This change in the estimated date of the extinction of the giant shark is relevant, since it places it long before a series of ancient seals, walruses, sea cows, porpoises, dolphins and whales disappeared, about 2.5 million years ago. Therefore, the theory that the extinction of the megalodon was directly related to the disappearance of all that marine biomass is weakened.
Similarly, the hypothesis that some cataclysmic event at the planetary level would cause a mass extinction of creatures is losing force. “It is possible that there was a period of faunal turnover (many species go extinct and many new ones appear) instead of a sudden and catastrophic extinction caused by an astronomical cataclysm, such as a supernova,” suggests Boessenecker.
Researchers speculate that competition for the megalodon from the emergence of the modern great white shark was one of the most likely reasons for its extinction. Great whites first appeared about 6 million years ago, but only in the Pacific. 4 million years ago they were already all over the planet.
“We propose that this brief overlap (from 4 million years ago to 3.6 million years ago) was enough time for the great white sharks to spread around the world and overtake the megalodon, leading to its end,” concludes Boessenecker.
Image: Robert Boessenecker.
