From the Academy to the Arctic
March 13, 2012
By Mary Alice Hartsock
To catch a glimpse of creatures that lived 375 million years ago, you will probably have to travel to a museum or research institution like the Academy of Natural Sciences. If you’re Dr. Ted Daeschler, the Academy’s vice president for systematics and the library, your search will take you all the way to the Arctic.
Almost 20 years ago, Daeschler, a vertebrate paleontologist, began studying Devonian age fossils in the Catskill Formation of northern Pennsylvania. In 1999, he and his research partner, Dr. Neil Shubin of the University of Chicago, began seeking other sites that would broaden their knowledge of the era. That’s when they learned about a group of 380- to 370-million-yearold rocks in the Nunavut Territory of Arctic Canada.
"The rocks attracted us because they came from a time period with evolutionary events that interested us," Daeschler explains. "The rocks also were deposited in environments such as streams, deltas, and lagoons that could preserve the animals that we sought. And the layers of rocks are clearly visible at the surface, which improves our ability to search carefully for fossils in as much rock as possible."
Daeschler, Shubin, and the team have taken seven successful trips to the region, several of which focused on the monumental discovery of Tiktaalik roseae, a 375-million-year-old fossil lobe-finned fish with many features only seen in tetrapods (limbed animals). Tiktaalik roseae is the best example of the evolutionary transition between finned and limbed animals.
In July 2011, the team traveled back to Nunavut for a three-week expedition.
"Ideally, our trip would lead us to more fossils that help us understand additional steps in the transition from finned to limbed animals," Daeschler says. "Our main goal was to study the rocks and fossils in a window of time that we had not yet sampled fully.
"We must use our time in the field efficiently, so we studied geological maps and publications, topographic maps, and aerial photographs. As we entered the field, we did an aerial survey, and then we put down our camp near the most promising areas."
Covering 35 square miles on foot and logging 13 fossil sites, the team collected geological information and fossils, many from armored and lobe-finned fish. Visit ansp.org/nunavut to read Daeschler's blog about his findings and the team's daily routine.
Upon his return to the Academy, Daeschler, along with paleontology staff and volunteers, will unwrap, organize, and label the specimens for future preparation. "We are finding that these fossils are from different kinds of animals than those found during earlier expeditions," Daeschler explains. "This may be because we crossed over onto the ancient shoreline and delta systems.
"Another possibility is that the nature of these rocks preserved a different set of fossils," he suggests. "Also, we are looking at a slightly different slice of time in which certain animals could have become extinct."
Though the fossils eventually will be returned to Canada, researchers will continue to learn from them. Scientists who specialize in other fish groups may discern more new kinds of fossil animals. Others may investigate the way these creatures interacted with their environments, or they might study similarities and differences between fossils from various study sites.
"There will be additional questions and new analyses for decades or even centuries based on what we found," says Daeschler. "It’s a treasure trove of information."