Remains of an ancient elephant discovered earlier this year in western Missouri make it among the oldest mammoths found in North America, Lawrence paleontologists have determined.

Craig Sundell, a Lawrence paleontologist, displays the tooth of what is believed to be one of the oldest mammoths found in North America.

The fossil, uncovered in July on a farm near Grain Valley, Mo., gives credibility to a relatively new theory that mammoths immigrated to the continent from Europe and Asia about 500,000 years ago — and not 250,000 years ago, as previously thought.

“This was one of the first critters that lumbered over,” said Craig Sundell, a paleontologist who lives in Lawrence.

Sundell said he and Kansas University scientists working at the site had previously assumed the bones belonged to a mastodon, a mammal that lived in North America from 10,000 to 50,000 years ago. After all, he said, 90 percent of elephantlike bones found in the region are mastodons.

But a tooth that Sundell uncovered during digging indicated the bones were that of a mammoth that probably died when it came to a glacial lake for a drink. The tooth, found around the end of August, has wide ridges, which indicates it is from an early mammoth.

The remains were discovered by a contractor who was digging a lake behind the home of Steve and Debbie Gildehaus in eastern Jackson County. Other ancient animals were found at the site, including a horse, sloth, armadillo and deer.

Sundell said digging was complete at the site. But Wakefield Dort, a retired KU geology professor, plans to conduct paleomagnetic testing to further determine the age of clay in the area.

Sundell said the mammoth would be shipped to the Science City museum in Kansas City, Mo., for temporary display and eventually would be given to the Grain Valley Historical Museum.

KU researchers eager to study prehistoric find (7-7-04)

“This is not something that’s going to make the cover of Nature or Science (magazines), but it’s still important from a regional perspective,” Sundell said.