A fossil of an intact molar belonging to a Pacific mastodon, a tusked mammal that went extinct almost 12,000 years ago, was recently discovered in a dry creek bed in San Mateo County.
A geomorphologist found the fossil by accident while conducting field research for a different project at a nature preserve in the Midpeninsula Regional Open Space District.
The Pacific mastodon — scientific name Mammut pacificus — was a large herbivore with a trunk and tusks that went extinct around 11,700 years ago, according to a news release issued by the Midpeninsula Regional Open Space District.
Researchers believe that the species was active in what is now California, Oregon, the Rocky Mountains of the Western United States, and parts of Mexico.
Unlike mammoths, which were similar in appearance and fed on grasses, mastodons used their trunk to strip leaves, fruits, and soft shoots of woody trees.
“The tooth itself is in immaculate condition. It’s the most complete mastodon molar from our area, and the most spectacular mastodon molar that I’ve ever seen,” said paleontologist Wayne Thompson in the news release.
Thompson is also the owner of Pacific Paleontology, a consulting firm that provides compliance guidance for the management of fossils found on construction sites.
“It’s another puzzle in the Ice Age saga that we can put into place,” Thompson added.
The Midpeninsula Regional Open Space District has donated the fossilized molar to Stanford University’s Doerr School of Sustainability, where researchers will use carbon dating to find its exact age.