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SPECIAL COVERAGE: Living With Wildfires: San Diego Firestorm 10 Years Later

Extinct California Porpoise Discovered In San Diego Had A Major Underbite

Look At The Underbite On This Extinct Porpoise

Protruding lower jaws are no longer seen on modern porpoises. Researchers say the disappearance of this fairly advanced feature illustrates how evolution doesn't always progress in a straight line.

Twenty-four years ago, a San Diego man saved a fossil from being run over by a bulldozer. This week, it was finally identified as the skull of an unusual — and now extinct — porpoise.

Twenty-four years ago, a San Diego man saved a fossil from being run over by a bulldozer. This week, it was finally identified as the skull of an unusual — and now extinct — porpoise.

It all started when San Diego Natural History Museum paleontologist Richard Cerutti was out monitoring the site of a new Chula Vista development when he spotted a pointy object poking out of the soil, dangerously close to a massive bulldozer.

"We keep them from backing up," Cerutti said. "They sometimes hit fossils."

If he hadn't been there in 1990, the skull would've been buried for good.

Cerutti knew right away the specimen was special. It looked sort of like a modern dolphin skull. But it had a massive underbite, it's lower jaw jutting out like a probe. That feature is not seen on any porpoises living today.

The skull has been on display periodically in the museum's Fossil Mysteries exhibit for two decades. But part of the mystery has now been cleared up. This week, researchers identified the skull as belonging to an extinct porpoise living in California three million years ago, back when much of San Diego County was underwater.

Photo by Bobby Boessenecker/San Diego Natural History Museum

Semirostrum ceruttii may have used its extended lower jaw to feel along the ocean floor for prey.

Tom Deméré, the San Diego Natural History Museum's curator of paleontology and one of the authors behind the new research, said, "This is something new, something brand new. Not only new, but bizarre. In the sense that this animal we found has a structure in the lower jaw that's not represented in any living dolphin or porpoise."

Researchers named it Semirostrum ceruttii, in honor of the man who found it.

"I was really surprised," Cerutti said, who was informed about the new species' name only hours before the research paper's publication. "When you're in this business, this is kind of the reward after years and years of finding fossils."

The skull currently is on display at the museum.

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