In the 2018 film The Meg, a 75-foot shark terrorizes the ocean. The actual science behind that number, the research that established how large Megalodon could really grow, rested on a single set of vertebrae dug out of a clay pit in Gram, Denmark, in the late 1970s, but when researchers moved the specimen out of its original research lab after publication, it was misplaced, leaving behind only photographs.
The turnaround came in the late 2010s, when a museum employee at the Geological Museum of Copenhagen noticed some boxes of fossils that had been sitting overlooked in storage. They turned out to be the missing vertebrae.
A new study published in Palaeontologia Electronica reports what researchers found when they finally examined them again. The vertebrae confirmed the maximum size estimates that had been built on photographs. CT scanning showed the shark was at least 64 years old when it died. And the rocks surrounding the bones contained what appears to be the remains of a basking shark, the first evidence in the fossil record of what Megalodon actually ate.
“The rediscovery of the vertebrae was a true delight because they empirically confirm the maximum vertebral diameter of 23 cm reported in the literature,” said lead author Kenshu Shimada in a press release. “The specimen not only represents the largest shark vertebrae known to date but also the largest fish vertebrae ever recorded to our knowledge.”
Read More: 18-Million-Year-Old Megalodon Teeth Reveal the Predator's Surprising Diet
Megalodon Size Estimate Confirmed by Lost Vertebrae
No complete Megalodon skeleton has ever been found, so size estimates rely on comparisons between vertebral diameters. The most recent maximum estimate is roughly 80 feet (24.3 meters), with a possible weight of around 94 tons. That figure comes from comparing the Danish vertebral diameter of about 9 inches (23 centimeters) with a more complete string of vertebrae from Belgium, thought to belong to a roughly 54-foot individual.
The larger Danish diameter allowed researchers to extrapolate a much bigger animal, but until now, that calculation rested entirely on photographs rather than the physical specimen. With the original back in hand, those calculations now rest on physical evidence.
“Size matters when it comes to understanding the biology, ecological impact, and geographic distribution pattern of this extinct giant predator,” said Mette Elstrup, the Head of the Natural History section of the museum.
The clay pit in Gram also sits further north than any other verified Megalodon site in the world. Larger Megalodon remains tend to turn up in colder waters, and this specimen fits that picture.
How CT Scans Revealed the Shark’s Age
Megalodon's skeleton was made of cartilage rather than bone, which meant most of it rotted away long ago. Vertebrae are among the few structures that are sufficiently mineralized to survive, making them unique and particularly valuable.
To find out how old this individual was, the team scanned for growth bands, rings that form over time, the same way they do in trees. The scans revealed the shark was at least 64 years old when it died and could theoretically have lived to 96.
Fossils Point to Megalodon’s First Known Meal
The rock surrounding the vertebrae held one more surprise — fragmentary gill structures and tiny scales from a basking shark, a species that can grow to substantial size but is much smaller than Megalodon. The researchers ruled out the possibility that the vertebrae themselves belonged to a basking shark, since basking shark vertebrae have a different shape and have been found separately at the same site. They concluded the basking shark remains were stomach contents.
For a species known almost entirely from teeth, the vertebrae that spent four decades in a storage room have turned out to say more about how Megalodon lived than anything else recovered from the species so far.
Read More: Why Mammoth Cave Preserves Shark Fossils Unlike Anywhere Else
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in Palaeontologia Electronica: Rediscovery of the associated gigantic vertebrae of the extinct megatooth shark, Otodus megalodon, from the Upper Miocene Gram Formation in Denmark, and comments on its paleobiological significance and the maximum possible size of the species
