Incidental basking shark fragments found in the surrounding rock likely represent Megalodon diet rather than belonging to the basking sharks themselves.

The authors include Kenshu Shimada of DePaul University, Mette Elstrup and Trine Sørensen of the Museum of Southern Jutland, Henrik Lauridsen of Aarhus University, and Mikael Siversson of the Western Australian Museum.

Micro-CT imaging of growth bands estimates the shark was at least 64 years old at death, with a potential maximum longevity around 96 years.

The 1978 discovery in the Gram Clay Pits yielded approximately 20 Megalodon vertebrae, including the 23 cm diameter vertebra, forming the basis for maximum size estimates of Otodus megalodon.

The fossils come from a deep offshore seabed dating to about 10.8 million years ago, a time when the area hosted a rich marine ecosystem including sharks, rays, fishes, marine mammals, seabirds, and sea turtles.

Reanalysis of the 23 cm vertebral diameter supports a maximum body length of about 24.3 meters (80 feet) for Megalodon, aligning with earlier size assessments.

Even without a complete skeleton, combining vertebral size, growth bands, and surrounding microfossils improves understanding of Megalodon’s size, growth, lifespan, and feeding ecology while acknowledging remaining uncertainties.

The box contained two partially preserved vertebrae, numerous small fragments, and casts of vertebrae, leaving the extent of original material only partially certain.

Imaging large, low-contrast vertebrae posed technical challenges, yet the team generated over 100 GB of micro-CT data to support the analysis.

Surrounding sediment revealed tiny scales and gill structures that may belong to a basking shark, suggesting possible prey remains associated with Megalodon and evidence of a broader, opportunistic diet.

A rediscovered Megalodon vertebral specimen from Gram Formation in Denmark confirms a maximum vertebral diameter of 23 cm, reinforcing estimates of a body length around 24.3 meters (80 feet) and solidifying its status as a giant predator.

The study highlights the ongoing value of museum collections for new scientific insights and notes that additional discoveries may still lie hidden in old specimens.