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(Picture credit score: Artwork by Clarence (Shoe) Schumaker, picture courtesy of the Calvert Marine Museum)
About 15 million years in the past in a heat coastal sea overlaying what’s now southern Maryland, the ocean floor immediately erupted in a violent upheaval as a shark the dimensions of a five-story constructing — the mighty and big megalodon (Otodus megalodon) — launched itself at a whale close to the floor, clamping its 250 serrated tooth across the whale’s midsection. Because the struggling pair broke the floor in a bloody breach, the drive of the assault bent the whale’s again and triggered a violent compression fracture.
That is the situation proposed by scientists who lately examined two of the whale’s fractured vertebrae and one megalodon tooth, which had been discovered shut collectively in Maryland’s Calvert Cliffs, a website relationship to the Miocene epoch (23 million to five.3 million years in the past). The researchers described the whale’s accidents — and what might need triggered them — in a brand new examine, revealed on-line Aug. 25 within the journal Palaeontologia Electronica.
“We solely have circumstantial proof, but it surely’s damning circumstantial proof,” mentioned Stephen J. Godfrey, a curator of paleontology on the Calvert Marine Museum in Maryland and lead writer of the examine. “That is how we see the story unfolding,” Godfrey advised Reside Science. “Though there are limitations to what we will declare, and we wish the proof to talk for itself.”
The scant stays of what was probably a 13-foot (4 meters) whale, relationship to about 15 million years in the past, had been initially found by Mike Ellwood, a Calvert Marine Museum volunteer and fossil collector. It was not potential to find out if the specimen was a toothed whale, a baleen whale and even a big dolphin, however Godfrey was immediately enthralled nonetheless.
“When it comes to the fossils we have seen on Calvert Cliffs, this sort of damage is exceedingly uncommon,” he mentioned. “The damage was so nasty, so clearly the results of critical trauma, that I needed to know the backstory.”
Associated: What was megalodon’s favorite snack? Sperm whale faces
Godfrey suspected that he may study extra by trying contained in the broken vertebrae with CT scans, and a neighborhood hospital provided to assist assess the fossil with trendy medical imaging strategies. The scans confirmed a textbook compression fracture — a sort of break by which vertebrae crumble and collapse — that was so distinctive in its sample as to be immediately recognizable.
“Any radiologist would have a look at this and acknowledge the pathology,” Godfrey mentioned.
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The scientists additionally found that the membrane surrounding the bone, often known as the periosteum, had produced new bone after the damage. No matter whether or not the periosteal bone fashioned to restore the wound, because it usually does in people, or as the results of an an infection or arthritis, the expansion of recent bone post-injury means that the whale lived for a number of weeks after experiencing the fracture.
However as compelling because the megalodon hypothesis could also be, different components may have fractured the whale’s vertebrae hundreds of thousands of years in the past. Extinct marine megafauna aside from a megalodon — resembling its shut relative Otodus chubutensis, the false mako shark (Parotodus benedenii), the Miocene white shark (Carcharodon hastalis) or perhaps a macroraptorial sperm whale (Physeteroidea) — may have delivered equally punishing blows. It is even potential that the whale ingested poisonous algae and vigorously convulsed till the animal basically broke its personal again, the examine authors instructed.
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However Godfrey thinks a megalodon assault is probably the most believable rationalization. For one factor, there’s the sheer magnitude of the trauma — one vertebra really telescoped inward from the drive of the opposite vertebra smashing into it. “It is simply so excessive when it comes to the violence,” Godfrey mentioned, including that it is onerous to think about any seizure or convulsion packing such a punch.
After which there’s the megalodon tooth, discovered alongside the vertebrae. Nearer examination of the tooth revealed that its tip broke off throughout the Miocene, probably after putting one thing like bone. And whereas it’s potential {that a} Miocene megalodon could have merely shed its previous tooth whereas swimming over a long-dead whale carcass, or misplaced it whereas looking an injured whale and feeding on its stays, it’s tempting to reconstruct a scene by which the apex predator of the day blunted and in the end misplaced its tooth whereas dealing the compression fracture itself.
“We do not know the complete repertoire of predatory strategies that megalodon may have employed, but it surely’s potential that, like residing sharks, they ambushed their prey from beneath,” Godfrey mentioned. Throughout a high-energy breach with prey between its jaws, he defined, the megalodon may have simply flexed the whale’s spine in opposition to gravity with sufficient drive to create the noticed accidents.
However Godfrey is not ruling out various explanations. “Our paper covers the breadth and scope of the situations that might have triggered this sort of harm, and hopefully that may spur additional analysis,” he mentioned. “These are wonderful tales. We get to inform the preliminary story, however whether or not that seems to be the very best rationalization actually stays to be seen.”
Initially revealed on Reside Science.
