By David McKay Wilson
Back in the day鈥攕ome 66 million years ago鈥擜ntarctica was a verdant playground for lumbering dinosaurs, rangy reptiles and lush expanses of flowering plants, with its surrounding waters teeming with all sorts of fish.
Today, it鈥檚 mostly ice-covered, though a spit of rocky coastline along the James Ross Island Group by the northern Antarctic Peninsula is revealed during the Southern Hemisphere鈥檚 summer. That provided the landscape for Kerin M. Claeson, PhD, associate professor of anatomy, and her 13-member international team of paleontologists to prospect for fossils this past February and March.
There, the team spent five weeks combing the peninsula for sedimentary rocks that held evidence of what life was like before a huge meteorite slammed into the Yucatan at the end of the Cretaceous Period, sending into extinction 65 percent of the world鈥檚 species.
They hit pay dirt.
Kerin M. Claeson, PhD, associate professor of anatomy, prospected with an international
team of paleontologists.
The team boxed up more than a ton of fossils, including Dr. Claeson鈥檚 hefty haul of ancient marine vertebrate fossils. Her discoveries included rows of fish scales, a slew of shark teeth, articulated vertebrae, parts of fish skulls and dense masses of disarticulated bone. Her colleagues, on the hunt for dinosaur fossils in a land rarely examined by paleontologists, dug up bones of a marine reptile called the giant plesiosaur. They also found fossils of dinosaurs, birds and plants that once thrived there.
In a region known for its inhospitable weather, the Antarctica Peninsula Paleontology Project鈥攃alled AP3鈥攅xperienced a spate of good weather during the late austral summer. Dr. Claeson spent ten days camping in the barren Antarctic wilderness.
鈥淲e were very lucky,鈥 says Dr. Claeson. 鈥淭here were many days without snow or rain, so lots of rocks were exposed. We really covered a lot of ground.鈥
The trip to Antarctica was the latest field trip for Philadelphia College of Osteopathic Medicine鈥檚 newly minted associate professor, who holds a bachelor鈥檚 degree in geology from Stony Brook University, a master鈥檚 degree in organismic and evolutionary biology from the University of Massachusetts and a doctoral degree in vertebrate paleontology from the University of Texas at Austin. She was researcher-in-residence at Ohio University鈥檚 Center for Ecology and Evolutionary Studies and an instructor of anatomy at Ohio University Heritage College of Osteopathic Medicine before arriving at PCOM in 2012.
She鈥檚 now about to begin her fifth year of teaching anatomy to first- and second-year medical students while involved in myriad research projects. She鈥檚 on the team that teaches the anatomy lab for 13 weeks to 270 incoming osteopathic medical students.
Dr. Claeson lectures on development in the early stages of life to the first-year students and teaches neuroanatomy to second-year students.
Like paleontologists, Dr. Claeson says medical students need to develop their 鈥渟earch image鈥 when coming to understand the human body. 鈥淭hey are going to learn how to look at things, and feel things,鈥 she says. 鈥淎nd they get better at seeing.鈥
By late June 2016, as she was preparing to teach an anatomy course for physician assistant students, Dr. Claeson awaited the fossil shipment. Of the 14 boxes she packed while in the field, two will come to her lab at PCOM for study. The rest will be stored at the Carnegie Museum of Natural History in Pittsburgh, where she can take the findings out on loan for further examination.
She says there was the possibility that researchers found fossils with evidence of new species from the prehistoric world.
Dr. Claeson was recruited for the Antarctic research sojourn by Matthew C. Lamanna, PhD, assistant curator of vertebrae paleontology, Carnegie Museum of Natural History, who wrote the National Science Foundation grant to fund the expedition, and Patrick O鈥機onnor, PhD, a professor and paleontologist at Ohio University.
Dr. Lamanna says Dr. Claeson took on a leadership role at the AP3 camp on Seymour Island, where she came upon a layer of sedimentary rock that was loaded with fish fossils. He notes it could be one of the few deposits of fossils directly linked to the extinction event. He says Dr. Claeson became enthused at the discovery.
鈥淪he鈥檚 tough as nails, whip-sharp and super driven,鈥 says Dr. Lamanna. 鈥淪he gets so focused when she is in the field. And she was effectively the driving force behind the Seymour camp.鈥
Dr. Claeson鈥檚 research interests are broad. At PCOM, she鈥檚 planning to study the effect of nutrition and light on the skeletons of zebrafish in her new Evans Hall fish lab, where she鈥檚 in the process of breeding scores of fish for project. 鈥淚n a single night, we can get 100 fish that are bred,鈥 she says. 鈥淲e鈥檙e getting our numbers up so we can begin to run the experiments.鈥
She鈥檚 working with colleagues in London on the fossil of a giant sawfish, which was
unearthed in a Moroccan limestone quarry by workers with an eye for chunks of rock
that may shelter fossils within.
Another one of Dr. Claeson鈥檚 initiatives looks to create a digital catalogue for paleontology and evolutionary research studies that fill eight file cabinets, which she was given from a Kentucky collection that dates back to the 19th century.
She鈥檚 also working with graduate students on an issue at the heart of osteopathic medicine: the effect of manual manipulation on the musculoskeletal structure of patients. She鈥檚 using the analytic tools employed by paleontologists to detect shape changes, this time to provide evidence of the impact osteopathic manipulative medicine has on the human body.
It might seem odd to have a paleontologist who scours the Antarctic shores for fossils teaching medical students about the intricacies of human anatomy. But Dr. Claeson says many of her colleagues have found positions teaching anatomy because the process used to study fossils can be adapted to study the human form. 鈥淲hen we are looking at anything that鈥檚 extinct, we don鈥檛 get to watch behavior, or know anything up front,鈥 she says. 鈥淲e are foundationally anatomists. We see the way an animal was formed, and then extrapolate behavior from what we see.鈥
Dr. Claeson鈥檚 study of OMM鈥檚 impact on the skeletal structure is a case in point. This past year, she conducted research that analyzed patients with chronic back pain. The patients were being treated by DOs and OMM fellows who hypothesized they could reduce pain and use manual manipulation to improve their patients鈥 posture. The study began by taking photographs of patients鈥 backs and analyzing those images by using a system called geometric morphometrics, which created landmarks on the photos.
Another round of photographs was taken after the OMM treatments, with the landmarks then compared to see if the body鈥檚 shape had changed. The study was detailed in one of the myriad research posters that line the corridor outside Dr. Claeson鈥檚 office.
鈥淭he students spent many, many days with the clinicians, photographing the treatments, and marking those digital photos,鈥 she says. 鈥淲e were able to see that there was some morphological change associated with the treatment.鈥
Physicians and paleontologists even share tools of their trades. Among those in regular use are noninvasive digital imaging systems. Dr. Claeson is using a CT scanner on her study of a giant saber-toothed salmon fossil. 鈥淭he CT scan is a very useful tool,鈥 says Dr. Claeson, who clicks through CT scan files on her computer to show a visitor how the scan revealed the structure inside the rock. 鈥淲hen an animal becomes a fossil, the part that was bone is usually more dense than the rock, so the contrast works in your favor. We are able to begin to piece out what鈥檚 rock and what is bone as we digitally dissect the pieces.鈥
Inside her Evans Hall office, you鈥檒l find fossil-finding tools, such as the marsh pickax that hangs from the wall鈥攁 gift from the Society of Vertebrate Paleontology after she helped host a national conference while a doctoral candidate at the University of Texas. There鈥檚 also an aging Apple Power Mac G4 computer that runs a program cataloguing phylogenetic trees of fish species that cannot be read by newer computer software.
She sits at her computer in an upholstered chair that belonged to Tage Nielsen Kvist, PhD, the former chair of PCOM鈥檚 Department of Bio-Medical Sciences, who retired this year. 鈥淚鈥檇 always remarked that I loved that chair,鈥 says Dr. Claeson. 鈥淲hen I got back from the trip, it was here in the room.鈥
The AP3 expedition, which was sponsored by the National Science Foundation鈥檚 Office of Polar Programs, was several years in the works. The research team had been trying to get there for years. In 2013 and 2014, the team was prepared to embark on the US Antarctic Program鈥檚 research vessel, Laurence M. Gould. But heavy sea ice surrounding the James Ross Island Group made the passage impossible.
Undeterred by the Antarctic ice, by 2015, the team had upgraded their research vessel to the 308-foot-long Nathaniel B. Palmer, a National Science Foundation research ship designed for Antarctic ventures, and equipped with a small boat and helicopter to ferry the researchers to their far-flung research destinations if the sea ice proved too thick.
Then one of the warmest Antarctic summers on record melted the ice around the research region, which is located at about 64 degrees south latitude.
Getting to Antarctica takes time. The AP3 team flew two days to reach southern Chile, where they undertook five days of training in the intricacies of camping in the polar reaches. The ship then motored for four days through the Straits of Magellan, the Drake Passage and the Weddell Sea before arriving at their desolate destination.
On day trips, teams would be dispatched to their research sites on Vega or Seymour Island. While on the ship, they鈥檇 meet at 7:30 a.m. to learn about that day鈥檚 plan, await the weather report and decide whether to be transported by boat or helicopter. Then they鈥檇 be dropped off, and picked up hours later. If the snow started falling, they鈥檇 radio in for an earlier pick-up.
鈥淥ne day the snow piled up, but then the next day, we had a windstorm that blew it clean away,鈥 Dr. Claeson says.
Temperatures ranged from 20 to 50 degrees during daytime hours. While camping, Dr. Claeson slumbered in a sleeping bag that completely covered her head. She would awake to observe hoarfrost crystals on the tent. Once, she dried a pair of pants outdoors that had become wet while prospecting. It turned out that the water in the fabric froze instead of evaporating. 鈥淢y pants melted while I was wearing them,鈥 she recalls.
What made it so cold was the incessant wind, which would howl out of the south. The researchers would layer up with fleece, down parkas and windbreakers. Dr. Claeson had a pair of ski goggles in her pack, just in case the wind was really blowing, and put toe warmers in her boots on frigid days. If it got too cold, Dr. Claeson would simply drop and knock off a round of push-ups to warm herself up.
One glorious day on the Antarctic Peninsula started out so warm and sunny that Dr. Claeson had taken off her parka and rolled up her leg warmers when she set out with a colleague to prospect for fossils. But when they reached the peak of False Island Point off Vega Island, they were blasted by an icy wind, and scrambled to don their cold-weather gear.
On days that were simply too windy, the AP3 team would remain on board the research vessel, or hunker down in the makeshift labs at their camping site. The team鈥檚 microscopes then came in handy. Such days gave Dr. Claeson the time to prepare, identify and catalogue specimens that she鈥檇 found.
At night, the team would gather to eat dinner, talk about their research or watch a movie. If the night sky was clear, they鈥檇 venture outside to stargaze. One night the Southern Lights flickered green across the vast Antarctic sky.
While the team was primarily prospecting for evidence of prehistoric dinosaurs, Dr. Claeson focused on finding fossils of fish as she walked through the rock fields with a backpack filled with her research tools: a rock hammer, a chisel, a pickax, a whisk broom, a GPS device and a radio. 鈥淲henever paleontologists are looking for mammals or other vertebrates, you are always going to find fish,鈥 says Dr. Claeson. 鈥淲ater helps with the burying and hardening process. Major floods and disasters can create fossilizing potential, and where you have water, you will have fish.鈥
The team headed to rock fields where previous expeditions had made finds. When in the field, paleontologists have what Dr. Claeson calls a 鈥渟earch image.鈥 She鈥檒l be looking for a sedimentary rock, usually rounded, which may hold an answer to nature鈥檚 evolutionary history if a fossil is revealed once it is cracked open.
Dr. Claeson has an idea of the texture she鈥檚 looking for on a rock鈥檚 surface. In Antarctica, it was rocks that were shiny and black at the surface. 鈥淲hen the rock gets exposed to bad weather, the fossilized bone gets very dark and black,鈥 she explains. 鈥淥n the first day I found something like that, and then I kept looking around and kept finding them.鈥
On one day, she found shark teeth in rocks with a whitish tinge. On another day, she found rocks with fossils with a bluish tinge.
At other times, the team would come across actual bones on the ground as they walked, and looked, very closely. Near the end of the trip, on a hillside on Vega Island, the team found what turned out to be the bone of a dinosaur.
鈥淚t was a huge deal,鈥 she says. 鈥淲e needed to spend more time there. So we returned to the spot, lined up and crawled on our hands and knees. It reminded me of back in elementary school when a girl had lost an earring on the playground. Then we found another piece. If we鈥檇 had more time, we would have found more.鈥
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