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Turtles All The Way Down

Paleontologist Tyler Lyson follows the fossil record to ‘deep time’

Tyler Lyson uncovered his first mystery of paleontology as a 6-year-old boy in remote southwestern North Dakota. He was hunting rabbits with his brother “because that’s what kids do out there,” he says, when they came across a dinosaur jawbone half-buried in the earth. “My brother gave it a kick or two and took off after the rabbit. I stayed back with a stick and slowly carved out the jawbone. I kept it and still have it.” 

Lyson had caught the fossil-hunting bug. His passion for paleontology would eventually carry him across the country to study with prominent developmental biologist Scott Gilbert at Swarthmore, and, later, to a doctorate at Yale, and a two-year fellowship at the Smithsonian Institution. This month, he joins the Denver Museum of Nature and Science as the curator of paleontology. These days, Lyson’s discoveries are less on the scale of a single fossil and more on the level of solutions to long-standing puzzles of paleontology.

“Tyler is probably the person who discovered the ancestor of turtles,” says Gilbert, who remains Lyson’s mentor and friend. “He’s probably the leading expert in America right now in turtle paleontology—or certainly one of them.” 

Not bad for a kid from Marmarth, N.D., population 137.

Lyson’s success comes as no surprise to family and neighbors who watched him, as young as 7 or 8, arriving at the local hotel with his shoebox full of fossils to offer assistance to the world-renowned dinosaur hunters who visited his fossil-rich corner of the badlands. For $50 a day, he would help them with their digs. “I was a product of my environment,” Lyson says. “Not much was happening in the area, except during the summer, when, scientifically, lots was happening.”

In fifth or sixth grade, Lyson discovered a turtle graveyard that has yielded more than 100 skeletons, including a new species, Palatobaena cohen. Later, in high school, he discovered the now-famous “Dakota,” a 3.5-ton, 67-million-year-old duck-billed dinosaur fossil that has mineralized soft tissues, including muscle and skin. More recently, he made headlines for unearthing the so-called “chicken from Hell,” or Anzu wyliei, a 500-pound feathered-and-helmeted dinosaur with 5-inch claws.

Despite his important contributions to dinosaur paleontology, Lyson’s primary interest has always been turtles. This interest brought him to Gilbert, the Howard H. Schneiderman Professor Emeritus of Biology, who studies, among other topics, the development of turtle shells in embryo. On the afternoon Gilbert first met Lyson, he had been working late with students and had a train to catch. He warned admissions officers that he would have no time to meet with a prospective student. Lyson came to his office anyway. “We talked and talked and talked, and I missed my train,” Gilbert recalls. “He just knew so much about turtle biology.”

“Scott is a great scientist,” Lyson says of Gilbert. “He helped me to start thinking about the question from a developmental perspective. Swarthmore in general is very good at training people to become scientists. A lot of my classmates became Ph.D.s. They have a good way of setting everything up, having you ask the questions, not just memorizing facts but going through the scientific process with you.

“That whole honors thesis process was a really good thing,” he adds. “Outside examiners come in and question you about your research. That’s how it works in the scientific world. When you put out a paper for review, it doesn’t go to your adviser; it goes to your peers.”

His mentor jokes that he was stumped to find outside examiners who didn’t already have a personal relationship with the turtle phenom from North Dakota. “Out of the people who were most famous in the field, [Lyson] already knew about four of them, so it was hard to find someone he didn’t already know.” 

Since his time at Swarthmore, Lyson has published several influential papers, one co-authored by Gilbert, concerning the skeletal changes that had to occur for lizards to become turtles and that examined possible turtle ancestors. Lyson’s experience as a fossil hunter came in handy. “The fossil record is the only direct window into deep time,” he explains. “You can have all the molecular data in the world, and you’re still not going to be able to figure out what organisms looked like 50 or 100 million years ago.”

Thanks to his extensive excavations, in 2013 Lyson identified a probable turtle ancestor by following the fossil record back more than 220 million years into the past. “If you go back 210 or 215 million years ago, you would recognize turtles,” he says. “You wouldn’t recognize crocodiles or birds. Maybe not even mammals. But you’d recognize turtles. That speaks volumes about how successful that body plan is.”

Turtles have successfully survived multiple mass extinctions, Lyson says, but 49 percent of turtle species are now endangered. “They’re very well adapted to natural environmental change, but with humans they’re not doing so well,” he says. “I think it speaks to the severity of our current crisis [a combination of climate change, habitat fragmentation, and the use of turtles as luxury bushmeat].”

Perhaps the best way to protect turtles for the next 220 million years is to educate the public about science and lessons provided by the fossil record. Lyson contributes to this cause through his nonprofit, the Marmarth Foundation, which he founded while still a Swarthmore student. The foundation helps bring wannabe paleontologists and youngsters to the fossil-rich expanses of North Dakota. There, Lyson hopes, these amateurs might catch the same bug that nabbed him at 6, when he laid down his BB gun and picked up his first fossil.

“It’s not for everybody,” Lyson says. “It’s hot; it’s hard work. But for me, it’s key. I still get a thrill every time I find even a piece of fossil that has no scientific value. You’re the first person to lay eyes on this piece of history—even more so if it adds in some way to our understanding of the history of life on Earth. I still get a thrill.”