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The skull of Titanotaria orangensis, a 6-7-million-year-old tuskless walrus from Orange County.
- A 13-year-old fossil enthusiast found a walrus skull in a boulder in northern California in 2011.
- Eleven years later, a paleontologist has named the formerly unknown extinct species in his honor.
In 2011, a 13-year-old fossil hunter on a beach near bluffs in Santa Cruz, California detected the complete skull of an unspecified 5-million-year-old walrus species encased in a giant boulder.
His discovery has now led to the identification of that ancient species of walrus, which scientists named after the 13-year-old in his honor in a recent paper published in the peer-reviewed Journal of Vertebrate Paleontology.
Detecting Fossils
An enthusiast since the age of 9, Forrest Sheperd would go hunting twice a week, finding shells, shark teeth, and whale bones.
“I was just absolutely on fire and ecstatic about finding fossils,” he told.
“I had been fossil hunting enough to know what fossilized bone looks like,” he said.
So when he came across the boulder, he identified the shape which was probably indicating a skull, and with the help of his friend, he hauled the 70-pound rock back to his parents’ car.
Fossils
Sheperd, who’s in medical school now, credits the paleontologist at the Santa Cruz Museum of Natural History with identifying many of his fossil finds and connecting him with Robert Boessenecker, an expert in marine mammal fossils.
Eleven years after Sheperd found it, Boessenecker named the newly identified walrus species Valenictus sheperdi after Sheperd’s last name.
“This fossil was found by a 13-year-old kid,” Boessenecker told BI. “I think that’s really remarkable.”
Boessenecker used to comb the same beach looking for fossils. “I have been visiting there since I was 15 but Forrest got luckier than me” he said.
Toothless not tuskless
Between graduate school and earning his doctorate, he took more than 10 years to get out the skull, but as he finally started to remove the hard sandstone surrounding it, he get to know that there were no sockets in its jaw for teeth, just a place for its upper tusks.
As their was no teeth so it was cleared that it doesn’t belong to modern walruses as modern species have teeth, which they do not use to eat but use t communicate by clacking together.
Boessenecker determined the skull belonged to the genus Valenictus — the closest extinct relative to living walruses.
But because the new skull was older and larger than other Valenictus species and had some physiological differences, Boessenecker realized that it was an unknown species.
He promised to name it after Sheperd as his honor.
“That’s obviously such a huge accomplishment for any fossil collector to be able to not just find a cool fossil, but to be able to find a fossil that really contributes to our understanding in a big new way,” Sheperd said.
The walruses in California
Millions of years ago, more than a dozen walrus species roamed the planet. Today, only two of them are left, “which tells us that something unusual has been happened with walruses in the past years” Boessenecker said.
Ancient walruses used to live in California, which probably had a similar climate 5 million years ago to what it has now, Boessenecker said. But That’s wildly different from the frigid Arctic temperatures which today’s walruses prefer.
Between 2 million and 7 million years ago, something unusual happened to the west coast that led to the end of a lot of species.
“There’s all sorts of weirdos that you find in rocks” in California from that time, Boessenecker said. In addition to walruses, there were odd-looking marine mammals, unusual extinct birds, and strange fish.
“We had giant bony-toothed birds flying around up until about 2 million years ago or so,” he said. A lot of Valenictus’ bizarre companions started disappearing around the same time.
“So what happened on the west coast?” Boessenecker posed. “Why did we have this incredible species or faunal turnover?”
He said researchers thought it had to do with a drastic change in the geography of the California coastline that occurred about 3 or 4 million years ago.
Before the change, the Los Angeles Basin and southern San Joaquin Valley were shallow marine bays that made perfect foraging grounds for walruses and other marine mammals.
But changes in geographical conditions and the emergence of the Sierra Mountains both contributed to the loss of those marine bays and the walruses’ food supply, Boessenecker said.
