Immaculate mastodon molar found in California creek bed
A geologist surveying a California creek bed for a frog habitat project discovered a remarkably well-preserved Pacific mastodon molar, dating to at least
An exceptionally well-preserved mastodon molar, initially mistaken for a rock, has been discovered in a San Mateo County nature preserve. The fossil, from an adult Pacific mastodon, dates to at least 10,000 years ago and is now undergoing carbon dating at Stanford University.
Geomorphologist Brigid Lynch found the tooth this summer while her team from Balance Hydrologics was conducting a field survey for a habitat enhancement project. The project aimed to support the threatened California red-legged frog within the Midpeninsula Regional Open Space preserve on the San Francisco Peninsula. Lynch described the find as the most exciting of her geological career.
A Surprising Discovery
Upon first inspection, the object looked like an "oddly shaped rock" to the geologists in the field. It was quickly identified as a fossilized tooth from the last ice age. The Midpeninsula Regional Open Space District, which runs the preserve, sent the specimen to scientists at Stanford University's Doerr School of Sustainability for analysis in July.
Paleontologist Wayne Thompson, CEO of Pacific Paleontology, performed a preliminary examination. "The tooth itself is in immaculate condition," Thompson said in a statement. "It's the most complete mastodon molar from our area, and the most spectacular mastodon molar that I've ever seen."
The Pacific Mastodon
The tooth belongs to a Pacific mastodon (Mammut pacificus), a species first recognized in 2019. This ice-age giant was closely related to the more widely known American mastodon (Mammut americanum). Both elephant-like creatures lived in North America during the Pleistocene epoch, which spanned from 2.6 million to 11,700 years ago.
The Pacific mastodon, however, inhabited regions farther west. Its range included parts of present-day Mexico, California, Oregon, and the northern Rocky Mountains of the western United States. According to the Royal Alberta Museum, fossils reveal slight anatomical differences between the two mastodon species.
Scientific Significance and Future Study
Thompson called the newfound tooth "another puzzle in the Ice Age saga that we can put into place." The precise carbon dating results from Stanford University will provide a more exact age for the fossil. Researchers will also create a detailed 3D copy of the molar.
The Midpeninsula Regional Open Space District plans to use this replica for public outreach and education programs. The discovery highlights how routine environmental work can lead to significant paleontological finds, offering a tangible connection to the region's ancient past.
The fossil remains a property of the public preserve, ensuring it is preserved for scientific study and public benefit. The analysis continues to uncover details about the life and extinction of the Pacific mastodon on the West Coast.
