Jude Sparks became one of the world’s youngest amateur paleontologists when he tripped over the fossilized tusk of a prehistoric elephant. The 9-year-old was on a walk with his family in Las Cruces, New Mexico, when he encountered what he thought was fossilized wood.

“It was just an odd shape,” Jude, now 10, told The New York Times. “I just knew it was not something that you usually find.”

The Sparks family took turns guessing what animal the fossil came from. Jude’s younger brother Hunter thought the jaw resembled a cow, while Jude’s parents, Kyle and Michelle, assumed that it was some sort of elephant.

They took a photo of the fossil, then went home to do some internet detective work. When the family failed to find an exact match for the skull, they looked up an expert at New Mexico State University.

Biology professor Peter Houde quickly recognized the fossil as a stegomastodon.

The extinct animal closely resembles a modern elephant. No one knows exactly when the stegomastodon went extinct, but the most recent fossilized remains come from around 28,000 years ago.

That means stegomastodon could have coexisted with the first humans who populated North America. In fact, humans may have contributed to the large mammal’s demise.

Once Dr. Houde saw the photo and realized the significance of the find, he hurriedly worked with the Sparks family to locate and cover up the remains. Houde had to wait several months for the necessary permits, and he didn’t want to risk losing the fossils to an amateur fossil hunter.

In May, Houde received the permits. He invited the Sparks family to join his team of professors and students as they worked to carefully unearth the skull.

The team excavated the jaw and two pieces of a tusk.

Though the fossils are heavy (the jaw alone weighs 120 pounds), they are also extremely delicate. The team had to apply chemical hardeners as the fossils were unearthed, or the fossils would have disintegrated in the process.

“We’re really, really grateful that they contacted us, because if they had not done that, if they had tried to do it themselves, it could have just destroyed the specimen,” Houde said. “It really has to be done with great care and know-how.”

Houde estimates that the fossils are at least 1.2 million years old.

While some news outlets have referred to Jude’s find as a “dinosaur fossil,” that is incorrect. Most dinosaurs went extinct 66 million years ago when a large asteroid or comet smashed into the Yucatan Peninsula. The catastrophe killed off around 75 percent of all plants and animals on Earth.

This stegomastodon existed at a time when large mammals, like saber-toothed tigers and ground sloths—which could weigh over 3 tons—dominated the planet. Humans didn’t exist yet, but early hominids like Neanderthals and Homo ergaster lived in Europe and Africa.

Houde says that stegomastodons were common at the time, but complete skulls are rarely found. He believes Jude’s discovery to be just the second complete skull found in New Mexico.

It’s not clear where the fossil will end up, but Houde is rooting for it to stay at New Mexico State University. He told the university’s paper, “I have every hope and expectation that this specimen will ultimately end up on exhibit and this little boy will be able to show his friends and even his own children, look what I found right here in Las Cruces.” [sic]