Rafał Grodzki, a member of the Mazury Historical and Collectors Association, made the discovery while diving in a lake in the Mazury region.

Initially, Grodzki was unsure of the significance of the find. “It had a strange shape. I knew it was something, but I didn’t expect it to be millions of years old,” he said.

The fossil was later identified as a vertebra of a plesiosaurs. Adam Rylet, a paleontologist from the Polish Academy of Sciences, said that plesiosaurs were aquatic reptiles with flipper-like limbs and elongated necks that preyed on other marine vertebrates, particularly fish.

Rylet pointed out its detailed preservation, adding that the vertebra's lower part was identifiable due to the presence of two distinctive holes through which blood vessels passed.

It's presence in a Polish lake, however, does not indicate that plesiosaurs lived in the region. According to Rylet, these creatures were predominantly found in what is now England and Germany, and the fossil was likely transported to the area by glacial movements during the Ice Age.

Despite offers to sell the fossil on the black market, Grodzki chose to hand it over to paleontologists for scientific study.