Not Your Average Fossil Hunters

Stony Brook’s paleontologists are using extinct species to expand our knowledge of evolution and climate change

By Liza N. Burby

Alan Turner and Maureen O’Leary in his office with two drawers that hold fossils from Madagascar and New Mexico.

A laboratory workbench displays the tools and debris associated with fossil discoveries. There’s a saw that could be used in the dissection lab to cut open human bones, but here it opens the plaster and burlap jackets — much like the cast on a broken limb — that encase the rock surrounding fossils, which protects them from the elements in the field and for transport back to the lab. There’s also a jackhammer and a small drill that resembles a dental tool that is used to chip away at the rocks encasing the remains of extinct species, and various brushes. A waste bucket holds broken rock saved for the tiny minerals they contain to be used for radiometric dating. 

Paleontologists have been using some of these methods for two centuries. But these tools, housed in a lab in the Department of Anatomical Sciences in the Renaissance School of Medicine at Stony Brook University, are being used by internationally recognized researchers. What they’re looking for are anatomical clues that can explain the biology and relationships of living and extinct species.

That’s because paleontology isn’t just about collecting fossils, according to Alan Turner, a professor and department chair. It’s about trying to address clear biological questions about how the evolutionary process shapes an organism. What makes that possible is the newest tool at their disposal: advances in CT scanning, which allows them greater understanding about the parts of fossils they couldn’t see otherwise, like internal features of the bone.

“You can CT scan a skull of a dinosaur, and that is going to tell you something about its internal anatomy — brain shape, brain volume and how the different internal parts are related to each other,” Turner said. “You do that across enough animals, and now you’re looking at big patterns of shape change, and those patterns may track with behaviors or ecologies.”

Turner said the department’s research and teaching is unified by the evolutionary perspective that the vertebrate body, including our own, is shaped by natural selection, and that understanding how systems function — and fail — begins from this principle.

Success Leads to Success
The department has already had a long-lasting impact on fossil discovery. In the 1990s, David Krause, an emeritus distinguished service professor and world-renowned paleontologist, was the lead discoverer of a suite of remarkable fossils from the Late Cretaceous of Madagascar. These include the “devil frog,” scientifically called Beelzebufo, which at more than 16 inches long and weighing 10 pounds is the largest frog known to ever exist; as well as Majungasaurus crenatissimus, a 20-foot long theropod dinosaur, an on-campus cast of which is affectionately called “Stony Bones;” Simosuchus clarki, a rare, 2.5-foot long crocodile; and the 6-foot fossil of a small predatory theropod dinosaur called Masiakasaurus knopfleri.

Turner working on a plaster jacket of dinosaur bones from Late Triassic rocks near Qhemegha, South Africa.

Turner said this high-profile work from Madagascar has led to other projects within the department. “Stony Brook is known as a center for paleobiology — scientists who study the evolution, biology and extinction of plants and animals through the fossil record — and that helps attract more scientists who are themselves experts or up-and-coming talent in that field,” he said.

For instance, while he’s part of the team that still runs the Madagascar project, Turner — who joined the department in 2008 — also conducts research in New Mexico, where he and his team found some of North America’s earliest carnivorous dinosaurs, 215 million-year-old animals. In 2020 Turner had two studies published in consecutive issues of Nature, one from his work in Madagascar and the other from New Mexico. He said the first study was on a “truly bizarre” fossil bird from the Late Cretaceous of Madagascar.

“This discovery of Falcatakely forsteri helped better understand convergent evolution of complex anatomy and provides new insight into the evolution of face and beak shape in the forerunner of modern birds,” he said.

For the second he was part of an international team of researchers that discovered the evolutionary precursors of pterosaurs, flying reptiles that dominated the skies 200 million years ago who were a group of small dinosaur-like animals called lagerpetids. His work in New Mexico provided key fossils for this study.    

Assistant Professor Andrew Moore is co-author on an article, published in the journal Nature in June 2024 that demonstrates that soaring birds co-opt a part of their lungs to improve the function of the pectoralis muscle. Moore said the discovery highlights the potential for other, unknown secondary functions of the lung, which is an investigation that is an active area of his research.

Assistant Professor Kimberley (Kimi) Chapelle, who joined the department in February 2024, was recently part of an international team that discovered and named a new species of dinosaur from the Mid-Zambezi Basin of northern Zimbabwe. She said the new dinosaur, named Musankwa sanyatiensis, underscores the potential of the region for future paleontological discoveries.

Diversity of Life
“These discoveries directly address questions like how do these really big Earth history events help shape the origin and the diversification of animals?” Turner said. “Those are the kinds of impacts that the research among our faculty have. We push the boundaries of understanding for these really important moments in Earth history. We hunt for the right kinds of fossils at the right time to look at the interaction between the Earth and the things that were living on it.”

From left: Drew Moore, Kimi Chapelle and Josef Stiegler in the department laboratory.

All of this takes place in anatomical sciences rather than a paleontology department because of the purpose of the research, he said.

“Many biology departments explore other parts of the diversity of life. Much of their focus is on genetic data and the intersection of molecular mechanisms and how those relate to evolutionary and ecological processes,” he said. “However, the majority of things that have ever lived on the planet are now extinct and the only thing we get of them are their hard parts, no genetic data. The hallmark of understanding the past diversity of life, particularly when you’re talking about vertebrates, is understanding all of the little details about the hard parts.”

Part of that is understanding how the huge diversity of life is related and how soft tissue like the lungs, which Moore studies, interact with bones in ways that leave clues to reconstructing a more complete picture of a fossilized animal. To do so, Turner said, vertebrate paleontologists have to be comparative anatomists.

“Whether that is a dinosaur skeleton and the soft tissue that we know was attached to it, and the nerves that we know moved through the bone and the arteries that moved around them, whether that’s a dinosaur or a human, we’re all evolved from a similar pattern,” he said.

The faculty also bring their anatomy training to teach Stony Brook’s medical students, dental students and other health professionals in clinical anatomy.

Moore, who came to the department in 2018, said, “We’re focused on what they need to know to be successful clinicians. And yet it’s often impossible to ignore in conversations with students, why does this nerve do this unintuitive thing? Why are our guts laid out this way? Often you can’t answer these questions if you don’t go back in developmental and evolutionary time. There’s no getting around the fact that we are the product of our evolutionary history.”

World’s Oldest Puzzles
One way to study that history is through growth patterns, which is one of the foci of Chapelle’s work.

Kimi Chapelle holding an elephant bone near Lake Kariba in Zimbabwe.

“If you cut fossil bones and look at them under a microscope, you can actually estimate how old a dinosaur was when it died, how fast it grew, and what kind of growth patterns it had,” she said. “It’s kind of like a tree. Every year they’ll slow down their growth for a while because the resources aren’t sufficient and during that time, they deposit a line in their bones. Those lines allow you to estimate how much they grew between different seasons.”

She works with sauropodomorph dinosaurs, who appeared around 235 million years ago. She’s specifically looking at their growth and development and is currently studying fossilized eggs and embryos of several dinosaur species, like Massospondylus from South Africa and Mussaurus from Argentina. Her task is to look at them through micro-CT images and powerful synchrotron scanning to reconstruct them without having to physically remove the rock surrounding the fossil.

A recent image on her computer shows an eye socket, flat and thin skull bones, the vertebrae, the arm and leg bones, all curled up in the fetal position.

“I’m moving them around on the computer and trying to figure out what it would have looked like if it was actually in the correct position,” Chapelle said. “It’s one of the world’s oldest puzzles with some of the world’s oldest known dinosaur eggs.”    

She said her research focuses on the Late Triassic and Early Jurassic periods, specifically to explore the mass extinction event that devastated Earth at that time. “What did that do to diversity and the ecosystem? Which animals replaced which? We’re also trying to look at all of these growth dynamics to figure out what kind of strategies were they using to just make it through the extinction successfully?”

For Moore, who said he’s trained as a systematist — someone who tries to build out the evolutionary tree of dinosaurs and understand their evolution — that means comparing extinct dinosaurs to their closest living relatives. For that reason, he’s become an expert in bird anatomy, because birds are living dinosaurs. He’s particularly interested in skeletal pneumaticity, the presence of air-filled spaces inside bones.

“As mammals, we have air-filled spaces in our skull. But that phenomenon is something we also see in the post-cranial skeletons of birds and their extinct relatives,” he said. “By studying bird anatomy, we can better understand the respiratory soft tissues that invade bird bones and the functional benefits and structural consequences that come with having hollow bones. Then we can bring that information back into the fossil record to make better inferences, to come up with better ideas about why pneumaticity evolved, what it’s good for.”

Living Through an Extinction

Stiegler in New Mexico, 2024

The faculty are also interested in understanding past extinction events and how species adapted and survived. Research instructor Josef Stiegler, who came to the department in 2020, has been working in New Mexico in a quarry about a mile down the road from Turner.

“It’s this incredible place where lots of dinosaur fossils are available from early in the evolutionary history of dinosaurs,” he said. “I want to know what species are living at the time period that I’m digging in, who were they living with and when did they go extinct. That will help us to understand the mysterious, major extinction at the end of the Triassic Period that killed most of the reptile groups that were living at the time. We’re trying to find more animals to name new species and figure out what the level of biodiversity was before the extinction.”

Stiegler is currently working with the bones of a dinosaur that he says is the size of a poodle. “Ornithischians are all over the place in the Jurassic and Cretaceous, but they are almost entirely absent from the earlier Triassic fossil record, and I think this animal might be related to them,” he said, adding that they were mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. His recent discovery currently on his workbench at Stony Brook contains well-preserved hip bones, an arm bone and a leg bone.

Stiegler said the purpose of his work and that of his colleagues is to figure out how their research fits into the context of what we as humans need to understand.

“Today because of climate change, we see lots of animals going extinct, their populations diminishing,” he said. “We’re very much living through an extinction. And this end Triassic extinction, this mysterious one that I’m talking about that we don’t have a good handle on, some of the things that are happening now, like global warming, were happening then too. The event at the end of the Triassic was more severe than the one we’re experiencing now, but there’s a possibility that ours can get that severe. Understanding how animals respond, how ecosystems respond to warming, may give us insights into the future of our planet.”

Overlapping Interests

Artistic rendering of the sauropod dinosaur Mamenchisaurus sinocanadorum

Turner said because his faculty are interested in similar kinds of questions, there’s overlap to their work.

“We’re looking at the anatomy of different things and trying to figure out what the evolutionary story is that unites them,” he said. “We might be working on different organisms but often there is geographic overlap or overlap in the kinds of methods each of us uses. In the end, we are all interested in better understanding how groups are evolving, diversifying and perhaps, going extinct.”

Among their colleagues is Maureen O’Leary, a professor who joined the department in 1997 and has worked in Mali and Senegal. She studies the origin, evolution and systematics of the major groups of mammals and founded the database and web application MorphoBank in 2012. It’s the central repository for peer-reviewed morphological matrices for phylogeny reconstruction (building the tree of life). The software enables teams of scientists to study phylogeny using phenotype, the observable characteristics of an organism. O’Leary is focused on separate monographic descriptions of newly discovered fossils from the Late Cretaceous-Early Paleogene of North America, Africa and Mongolia.

“My current work is to put unknown fossils into the intellectual record, to describe them, to illustrate them, to talk about, to analyze where they fit in the tree of life,” she said.

Regardless of what period they each study, these paleontologists said they appreciate the public’s fascination with dinosaurs. Moore said his research, in which he demonstrated that a Chinese sauropod dinosaur called Mamenchisaurus sinocanadorum had a 15-meter-long neck, the longest of any sauropod or any animal, generated so much interest last year it showed up as a clue in the British game show “Only Connect!”

Moore said, “Extinct animals inherently draw the public’s attention and provide invaluable opportunities for evolutionary biologists and paleontologists to teach a broad audience about how evolution has worked to produce incredible organismal diversity, now and in the past.”

Liza N. Burby is the features editor and an award-winning journalist.

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