New Species of Fossil Whale Excavated From San Francisco Bay Area's Purisima Formation

Posted on February 5, 2014

Balaenoptera bertae


Fossils of an ancient whale species that lived 5 to 2.5 million years ago have been excavated from San Francisco Bay Area's Purisima Formation. The whale species, Balaenoptera bertae, was a close relative of minke, fin, and blue whales. The whale is estimated to have been 5 to 6 meters in length. The research was conducted by Robert Boessenecker, a Geology PhD student at New Zealand's University of Otago. He named the whale in honor of San Diego State University Professor Annalisa Berta.

Boessenecker was 18 when he first discovered the fossil site near Half Moon Bay in 2004, after being tipped off by a local surfer. Boessenecker excavated an incomplete skull of Balaenoptera bertae in 2005. He says it was encased in a hard concretion that took five years to remove.

Boessenecker says in a release, "The mix of marine mammals I ended up uncovering was almost completely different to that found in the North Pacific today, and to anywhere else at that time."

Boessenecker's findings were published in the journal Geodiversitas.

Image: Robert Boessenecker