Pomona Professor Part of Fossil Discovery

A Pomona College professor is making headlines for his role in uncovering a new fossil deposit from the early days of animal life.

Robert Gaines, Associate Professor of Geology, has co-authored a newly-published article on the findings he and several other scientists made in the Canadian Rockies in August 2008. The article appears in this month’s issue of Geology.

“It helps improve our understanding of how the animals evolved from one another,” Gaines said of the discovery, which uncovered eight new species and more than 1,000 fossils in all phyla of the animal kingdom.

Among the fossilized treasures found on the expedition is a new predator called Stanleycaris hirpex, the first of its genus and species to be discovered.

Gaines and his colleagues named Stanleycaris—“Stan,” for short—after the Stanley Glacier, which stands over their worksite.

The team collected fossils about 25 miles from the famous Burgess Shale site, which is known for its impeccably-preserved fossils from the Cambrian Period, when ocean-dwelling animal life rapidly diverged from single-celled organisms.

“The Burgess Shale is arguably the most important fossil deposit in the world,” Gaines said, adding that fossils from most other sites preserve only hard, skeletal structures. “Here in the Burgess Shale, we get guts and eyes and gills.”

The new fossil site is part of the thin Stephen Formation, a rock formation that stands alongside the more heavily explored thick Stephen Formation. The traditional Burgess Shale site is in the thick Stephen.

Gaines said he believes that the fossils found in the thin Stephen are about half a million years younger than those from the thick Stephen, although no one is sure how to date the fossils accurately.

As the sole geologist on a team of paleontologists focused mostly on biological anatomy, Gaines had a unique set of responsibilities on the expedition.

“One of my jobs was to measure and describe the whole [thin Stephen] Formation,” including spots where no fossils were found, he said.

“While the rest of us were hammering open slabs of shale to find fossils, Bob was logging the rock section bed by bed and taking samples for later analysis in the lab,” wrote Allison Daley of Uppsala University in Sweden—who worked alongside Gaines on the 2008 expedition and co-authored the Geology article—in an e-mail to The Student Life.

“His results placed the Stanely Glacier site into regional context and, ultimately, it was Bob who confirmed that this site was in a different paleoenvironment than other Burgess Shale deposits,” she wrote.

Gaines was invited to join the expedition in 2007 by Jean-Bernard Caron of the Royal Ontario Museum in Toronto. The team received permission from Parks Canada to collect fossils in the Burgess Shale region, which had been closed to paleontologists for the better part of a decade.

The unexpected quality and variety of fossils Gaines and his colleagues found is cause for celebration among paleontologists, who stand to gather much valuable information from newly discovered fossil deposits in the thin Stephen.

“We knew that the abundance of these organisms was something special,” Gaines said. “It’s a remarkable window into early life.”

The new deposit also calls into question previous assumptions about why the Burgess Shale is such an excellent source of fossils, Daley said in her e-mail. Paleontologists had thought that the outstanding preservation of Burgess Shale fossils had to do with an escarpment, or underwater cliff, that created a deep basin and a shallow shelf.

“The site at Stanely Glacier, however, was deposited in the shallower shelf area above the escarpment,” Daley wrote. “This means that Burgess Shale type preservation does not necessarily require close proximity to an escarpment, which means that we need to re-examine the method of preservation for these spectacular fossils.”

This revelation could open up new areas to exploration by paleontologists in search of Burgess Shale-quality fossils.

“Now that we understand that localities that yield fossil with Burgess Shale type preservation do not necessarily need to be located immediately adjacent to an escarpment, we can expand our search radius when looking for new fossil sites with similar preservation,” Daley wrote. “This potentially provides much more opportunity to find exceptionally preserved fossils, in the Canadian Rocky Mountains and in other Cambrian strata.”

Gaines returned to the Canadian Rockies with the team this summer for more research, which he said uncovered at least 12 new species. During the recent expedition, Gaines, who had never tried rock climbing, learned to collect samples from a rope and harness and continued to study the relationship between the thick and thin Stephen Formations.

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