A rare 1.2 million year-old fossil was accidentally discovered by a 10-year boy while he was hiking in the Las Cruces desert in the US.
The fossil is a 1.2 million year-old skull of stegomastodon – a prehistoric ancestor of elephants. According to Jude Sparks, who discovered the fossil, he was running when he tipped on part of the tusk. The boy landed on the ground next to the bottom jaw.
The Sparks family contacted Peter Houde, a professor at the New Mexico State University (NMSU) in the US. After the family contacted Houde, the jaw and two pieces of tusk were taken to the Vertebrate Museum at NMSU. In May, the family joined a team of scientists who worked for about a week to carefully unearth the skull.
Houde estimates the jaw weighs about 120 pounds and the entire skull as little as a tonne. While the skull may appear to be strong, it is quite delicate.
“The upper part of the skull is deceiving. It’s mostly hollow and the surface of the skull is eggshell thin,” Houde said. “An extremely large skull would be very heavy for the animal if it didn’t have air inside it to lighten it up just like our own sinuses.”
During the weeklong extraction process, 10 to 12 people helped at different times with the excavation of the stegomastodon skull.
Researchers painstakingly brushed away the last bits of dirt from the skull and tusk and applied chemical hardeners to ensure the ancient bones remained intact.
Acting like plastics, the chemicals harden and restore the strength that would otherwise be present in the bone as protein.
After the skull was unearthed, the team carefully coated the fossil with plaster and placed wood braces to protect and support it.
The skull was lifted from the dig site by a front-end loader and placed on a flatbed truck for the trip back to the university.
While the process to study and reconstruct the skull, jaw and tusks will take years to complete, Houde said that the stegomastodon fossil will eventually go on display.