Long-lost Otodus megalodon vertebrae have reopened questions about the giant shark while exposing the vulnerability of museum collections.
For decades, several enormous shark vertebrae sat unnoticed on a museum shelf. Once recognized, the long-missing fossils reopened a rare window into the life of Megalodon (now properly Otodus megalodon), one of the largest predators ever to inhabit the oceans.
Museums preserve much of the world’s scientific and cultural history, yet even important specimens can be misplaced. The rediscovery of these vertebrae shows that fossils believed to be lost can sometimes resurface and provide researchers with evidence that photographs and written descriptions cannot fully replace.
The newly examined remains are helping scientists reassess the size and growth of this giant shark, which lived from about 15 million to 3.5 million years ago. The findings support earlier estimates that some individuals may have exceeded 24 meters in length. By comparison, even the unrealistically oversized sharks portrayed in the Jaws films reached only 10.5 meters.
The analysis focused on several vertebrae from a single shark that lived about 11 million years ago and was found in Denmark. Because most of a shark’s skeleton consists of cartilage, which rarely fossilizes, vertebrae are far less common than teeth and jaws. They can also provide a clearer estimate of an animal’s overall size than a tooth alone. These specimens are the largest vertebrae known from any O megalodon (23cm in diameter).
Rediscovery unlocks new estimates
These important specimens were thought to have been destroyed in a move from the Geological Museum of Copenhagen (now part of the Natural History Museum of Denmark) to the Museum of Southern Jutland in 1989. The scientific records of them were limited to old photos and descriptions. A couple of these vertebrae have now turned up, having apparently sat on a shelf unrecognized for decades.
This allowed for the new study, which also estimated that a newborn O megalodon might be 3.6 meters long and live for nearly a century.
War has erased key fossils
All manner of unlikely and unfortunate actions can lead to the loss of fossils from museums.
Most obviously, this can happen during times of conflict. The Second World War saw the loss of dinosaur fossils on both sides of the conflict. The original specimens of the sail-backed dinosaur Spinosaurus were destroyed in Munich by an Allied bombing raid in 1944. Earlier, a number of specimens, including parts of the early dinosaur Thecodontosaurus, were destroyed in Bristol after an Axis raid in 1940.
These were not even the first losses from enemy action in international wars. In 1916, the Canadian ship SS Mount Temple was sunk by a German ship. Although it was mostly carrying wheat, it also had a cargo of dinosaur fossils from Alberta that were being moved to the UK. The cargo lists are vague, so we don’t even know what dinosaurs were on board.
Indirect action could be problematic too. In 1941, the Chinese attempted to move as many as 40 specimens of “Peking man” (Homo erectus), the first of our relatives to have human-like proportions, to the US to try to save valuable early hominid fossils from the invading Japanese forces. They never arrived, and might have been lost at sea after the ship they were on was sunk. Although it’s possible they never even made it on board the vessel.
Fragile specimens can simply vanish
Things can also be simply lost or fall apart. An apparent giant sauropod dinosaur similar to Diplodocus was named by the US paleontologist Ed Cope in 1877 as Amphicoelias fragillimus. He described it from a single, incomplete, fragile, but giant vertebra.
Cope gave differing measurements of the vertebra at various times, making it unclear quite how large it actually was. When he died, his collection was sold to the American Museum of Natural History, but they were never able to find this specimen. Given how fragile it was, it may simply have disintegrated on the shelf and been overlooked or thrown away.
Museums are not immune to losses either. If you have an enormous number of specimens (the Natural History Museum in London has an estimated 80 million objects in its collection), it is inevitable that one or two may simply get lost.
I’ve been an eyewitness to lost specimens turning up in a museum when a colleague spotted a dinosaur skull and pterosaur skeleton sitting on the wrong shelf like misplaced library books. Then there’s the more nefarious activities – I’ve heard of researchers deliberately moving specimens to make them hard to find so other researchers cannot examine them, and occasionally things are stolen from collections.
Disasters can erase entire collections
On top of this, natural disasters and accidents can wipe out history. The Fukushima earthquake and tsunami of 2011 in Japan caused major damage to the nearby Iwaki museum, with damage to some of the fossils in their collections. And in 2018, one wing of the National Museum of Brazil in Rio de Janeiro burned down, with the loss of many fossil specimens that were on display.
For all the examples raised here, museums are inherently safe places for specimens. There are millions and millions of fossils that have been held in institutions around the world for decades and even centuries. It is inevitable that accidents will happen, and that bad actors will cause occasional losses. Fortunately, at least on occasion, these do reappear and give us some exciting new research opportunities.
Reference: “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” by Kenshu Shimada, Mette Elstrup, Henrik Lauridsen, Trine Sørensen and Mikael Siversson, 14 May 2026, Palaeontologia Electronica.
DOI: 10.26879/1674
Adapted from an article originally published in The Conversation.
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