Museums exist to safeguard the physical record of the past, but even that record can go missing. A newly published study in Palaeontologia Electronica describes how a handful of fossil vertebrae from Otodus megalodon — long presumed destroyed — turned up unnoticed on a museum shelf decades after they were lost, and how their rediscovery has helped confirm one of the largest size estimates yet proposed for the extinct shark.
The vertebrae originated at the Geological Museum of Copenhagen, now part of the Natural History Museum of Denmark. According to the study, first reported by ScienceDaily, the specimens were believed to have been destroyed during a 1989 transfer of collections from the Copenhagen museum to the Museum of Southern Jutland. For more than three decades they were treated, in effect, as lost to science — until a couple of the vertebrae turned up, having apparently sat unrecognized on a shelf the entire time.
Why a few vertebrae can rewrite a size estimate
Otodus megalodon is known almost entirely from fossilized teeth and vertebral centra, since shark skeletons are cartilaginous and rarely preserve as complete fossils. That makes every surviving vertebra scientifically valuable: because vertebral centra grow in step with overall body size in sharks, their diameter is one of the primary inputs paleontologists use to estimate the length of an animal for which no complete skeleton exists.
The largest of the rediscovered Copenhagen vertebrae measures roughly 23 centimeters (about 9 inches) in diameter. Working from that and comparable specimens, the new study — led by Kenshu Shimada along with Mette Elstrup, Henrik Lauridsen, Trine Sørensen and Mikael Siversson, and published in Palaeontologia Electronica — reexamines the size and growth trajectory of the species. It confirms earlier estimates that the largest individuals of Otodus megalodon could exceed 24 meters (79 feet) in length, among the upper end of size figures proposed for the species, and estimates that newborns were already around 3.6 meters (12 feet) long at birth — roughly the size of an adult human several times over, before the animal had grown at all.
A specimen’s custody chain matters
The story is as much about museum recordkeeping as it is about shark biology. Otodus megalodon lived roughly between 15 and 3.5 million years ago, and went extinct long before humans existed to study it directly — every conclusion about its size, growth and biology depends entirely on what curated specimens survive, and on institutions being able to locate and correctly attribute them decades or centuries later. A specimen that is misplaced, or whose provenance is lost in an inter-institutional transfer, effectively stops existing for scientific purposes even if the physical object survives; that is exactly what nearly happened here across the 1989 move between the Geological Museum of Copenhagen and the Museum of Southern Jutland.
This is the same custody-and-provenance discipline that underlies research data management and specimen/sample identifier practice more broadly: a physical or digital research object that cannot be reliably traced back to its origin, chain of custody and associated metadata is, functionally, unusable as evidence — regardless of its underlying scientific value. The rediscovery in this case is a rare example of that failure mode being corrected rather than becoming permanent.
What the vertebrae confirm
The reexamined vertebrae do not overturn prior scholarship on Otodus megalodon size so much as reinforce it: the new analysis is consistent with, and adds physical evidence supporting, existing estimates that placed the largest individuals above 24 meters. Because so few vertebral specimens of this shark exist worldwide, each additional confirmed, well-documented example meaningfully strengthens the evidentiary basis for those estimates, rather than resting on tooth measurements and scaling models alone.
Source: ScienceDaily, “Lost megalodon vertebrae rediscovered decades later, confirming giant shark’s huge size,” based on Shimada, K., Elstrup, M., Lauridsen, H., Sørensen, T., and Siversson, M. (2026), published in Palaeontologia Electronica (DOI: 10.26879/1674).
