The missing part of an arm bone that belonged to a giant, prehistoric turtle was finally reunited with its other half- more than 160 years after the first half was found.
The fossilized bones belonged to Atlantochelys mortoni, a nearly 10-foot long sea turtle that lived when dinosaurs were alive some 75 million years ago, Live Science reported.
"This turtle was a monster, probably the maximum size you can have for a turtle," Ted Daeschler, from the Academy of Natural Sciences of Drexel University in Philadelphia, told the BBC.
The academy, which is over 200 years old, kept the other half all these years.
The upper part of the bone, which was half of the turtle's humerus, was found in the 1840s in New Jersey, the BBC reported. The earliest scientific description of the bone, dating back to 1849, said it was part of an ancient sea turtle.
But no other evidence of the turtle was found until an amateur fossil hunter discovered the bone's lower half near a brook in Monmouth County, New Jersey in 2012. The two halves turned out to be a perfect match.
"When we put the two halves together, we were flabbergasted," Daeschler told the BBC. "We said, 'no- that can't be!' We even turned them around trying to show they didn't match, but they're obviously supposed to be together."
News of the completed turtle bone will be published in an upcoming issue of the journal Proceedings of the Academy of Natural Sciences of Philadelphia.
Gregory Harpel, who discovered the bone's second half, didn't know it was a bone when he first saw it. He picked up what he thought was a brown rock in a secluded area along the brook.
"I started seeing the little holes in the bone that the blood vessels go through," Harpel told Live Science. "I thought maybe it was a dinosaur of some sort."
Paleontologists believe the bone was buried in one piece but broke in half due to erosion, Live Science reported. Researchers now know the fossil formed in the Mount Laurel Formation, an underwater rock formation where extinct marine life swam millions of years ago.
"We can more precisely know its age, and we can be much more confident about finding additional material in that same formation and therefore telling more about A. mortoni," Daeschler told the BBC.
