"There are more fossils than I'll ever be able to count in New Mexico," said Spencer Lucas, curator of paleontology at the New Mexico Museum of Natural History and Science.

Lucas was commenting on the recent excavation of a fossil found near the Las Cruces, New Mexico, desert last November.

While exploring the region's Organ Mountains with his parents and two brothers, then 9-year-old Jude Sparks tripped over something protruding from the earth.

In an interview with El Paso ABC affiliate KVIA, Sparks told reporters he immediately revealed the find to his brother, Hunter.

"Hunter said it was just a big fat rotten cow. I didn't know what it was. I just knew it wasn't usual."

The find was in fact not a big fat rotten cow but a stegomastodon, an ancient, primitive mammal that lived an estimated 1.2 million years ago. (Stegomastodons were early tuskers from the animal family Gomphotheres, a distant cousin of ancient mammoths and modern day elephants.)

Later that night, Jude's parents reached out to New Mexico State University Professor Peter Houde, who they discovered from a previous interview he gave on similar subjects. Houde and the Sparks family returned to the discovery site, finding an entire skull.

After securing funding, finding volunteers, and coordinating when the dig would take place, the university team and the Sparks family returned to the site to excavate the remains. A week after careful excavation, the fragile pieces, which Houde described as "egg-shell thin" to National Geographic.

Houde hopes the fossil will eventually be available for exhibit.

The Fossil State

This isn't the first time a stegomastodon has been found in New Mexico. In 2014, a bachelor party stumbled across a nearly intact fossil that was collected by the New Mexico Natural History Museum.

Coming across a stegomastodon fossil is considered a rare find. Lucas explained that fossils like those belonging to mammoths are relatively abundant in western portions of North America but for reasons not quite known, stegomastodons are less frequently found. According to Lucas, only a couple hundred have been found in the world.

One theory for why stegomastodons went extinct correlates to the arrival of mammoths.

Lucas's theory is that the ancient animals couldn't compete with mammoths. Both animals grazed on their surroundings, and could have competed for resources.

Houde theorized that climate change could have caused the animal's demise.

"They existed during a time when it was wetter and cooler," said Houde. "Las Cruces is now a desert."

Researchers don't know how many fossils lie buried in the desert, but if they're to be found anywhere in America, the southwest is a likely location. The region's naturally dry, rocky terrain create conditions needed to preserve bones for millions of years.

In interviews with local news, the Sparks family speculated that the recent rains in the area before the discovery might have helped to expose the fossil. Lucas agreed that this was well within the realm of possibility. He says that as rain erodes more sediment, discoveries are always possible.

"Erosion is a paleontologist's best friend."