Overview
- A geomorphologist working on a habitat survey for the Midpeninsula Regional Open Space District discovered an intact Pacific mastodon molar in a San Mateo County creek and the specimen was transferred to Stanford for study.
- Paleontologist Wayne Thompson described the tooth as the most complete regional mastodon molar he has seen and said its roots are unusually well preserved, which suggests the skull or other bones may still be nearby.
- Published reports give divergent ages for the tooth, with some accounts saying it is at least 10,000 years old while Thompson, citing field context, estimates roughly 50,000–100,000 years; laboratory radiocarbon dating at Stanford is pending.
- Midpen is withholding the precise find location to prevent disturbance, and Stanford plans high-resolution 3D scanning and replica production so the public can view copies while researchers study the original.
- The molar belongs to Mammut pacificus, an elephant-like Pleistocene browser that lived across parts of western North America, and its study could fill gaps about regional megafauna and local prehistoric environments.