By Rory Cahill
Thomas Holtz was just a toddler when he received two toy dinosaurs from his mother. One, a long-necked plant-eating Brontosaurus. The other, a carnivorous, two-legged Tyrannosaurus. The two animals looked completely different — yet somehow, both were called dinosaurs.
“Apparently, I looked at her really skeptically,” Holtz said. “Because how could these two things, which are so different looking from each other, be called the same thing?”
His mom didn’t know the answer, but she got him a book about dinosaurs and began reading to him. Soon, Holtz said, he decided he wanted to be a dinosaur when he grew up.
Sadly, Holtz did not achieve his childhood dream of becoming a dinosaur, but he did achieve the next best thing. He’s one of the world’s most accomplished and well-known paleontologists, and he’s taught at the University of Maryland for over 25 years.
Holtz attended Johns Hopkins University as an undergraduate before going to Yale University for graduate school. While at Yale, he studied under the influential paleontologist John Ostrom, who is known for his discovery of the raptor dinosaur Deinonychus. Holtz said he was one of Ostrom’s last students before Ostrom retired.
While finishing his doctorate, Holtz worked at the U.S. Geological Survey in Northern Virginia, where he studied a different kind of paleontology.
“The projects I was working on were micropaleontology, so we’re looking [at] fossil plankton,” said Holtz. The goal, he said, was to research the warmer climate of prehistoric Earth to predict the potential impacts of global warming.
“Instead of being super excited to find a single toe bone out in the field or something like that, you got 300 complete specimens on a slide,” Holtz said. “So it’s a very different world.”
He credited his work with the U.S. Geological Survey with improving his ability to analyze specimens and work with computers.
After four years at the USGS, Holtz returned to studying slightly larger fossils. He said that a coworker at the USGS, who also worked at the University of Maryland, invited him to give a colloquium talk at UMD to discuss his research. However, it soon turned out that this colloquium was what Holtz described as a “backdoor interview.”
At the time, Holtz said, the university administration was threatening budget cuts in the geology department, and the department planned to fend off these cuts by adding more popular classes.
“In the early 90s, early to mid-90s, dinosaur classes were beginning to become a thing,” Holtz said. “I came out and gave my departmental colloquium, and apparently it was good enough, so they hired me. First part-time, and then in the summer of ‘95 full-time.”
He’s been at the university ever since.
One of Holtz’s most important accomplishments as a paleontologist was his role in reshaping our understanding of tyrannosaurs. “Since the 1920s, there have been two major models as to where tyrannosaurs fit,” Holtz said.
Previously, many paleontologists considered tyrannosaurs to be part of the carnosaur family, along with other large theropods like the Jurassic-era Allosaurus. However, when Holtz started in paleontology, advancements in technology allowed for fossils to be examined with greater detail. Previously, he said, grouping animals was based more on “feel,” due to scientific limitations.
When Holtz started inspecting the bones of tyrannosaurs in more detail, it became clear that tyrannosaurs were not closely related to other large predatory dinosaurs. Instead, they were part of a group called the coeleurosaurs, which also included the iconic Velociraptor and all living birds.
“The results that I found were broadly similar, not exactly, but broadly similar to [results] being found by Fernando Novas, who’s an Argentine paleontologist, and Bernardino Perez Moreno, who’s a Spanish paleontologist,” Holtz said. “We’re coming at it from different data, but finding very similar results, that was encouraging.”
John Merck, one of Holtz’s colleagues at UMD, met Holtz while attending paleontology conventions in the ‘90s. “Even back then, he had a reputation for being an outstanding source of information about the state-of-the-art dinosaur paleontology,” Merck said.
While searching for a job, Merck received a phone call from Holtz, inviting him to join a new program that Holtz was setting up at UMD. “Without any discussion of what the salary would be, or anything like that, I just said ‘yes, absolutely,’” Merck remembered. Since then, Merck and Holtz have taught upper-level paleontology courses together.
“Tom is a highly energetic individual,” Merck said. “Back when I was in grad school, when he was just finishing up his Ph.D., he had the nickname – he didn’t know it, but we referred to him as ‘too much coffee man.’ Because he was, at that point, thin as a rail and his metabolism seemed to be running about twice as fast as mine.”
M. Eugenia Gold, a paleontologist at Suffolk University with a Ph.D. in comparative biology, is a former student of Holtz’s. She described his teaching style as “a mix of stand-up comedy, satire news and traditional lecturing, which is really engaging and really just fun to witness.”
Gold said she took all but one of Holtz’s classes while attending UMD, and that his teaching style has been a major influence on hers.
“He modeled the lecture style that I found really engaging as a student, and so I model my lecture style after what I witnessed in him,” Gold said.
Even now, as he enters his 60s, it’s clear that Holtz still loves paleontology. Holtz said he loves “the weird and wonderful nature of the animals,” and enjoys the challenge of studying extinct animals. He also appreciates that the public is interested.
Unlike many scientists who work in more obscure fields, he said, “I can share my love and interest in that subject with a broad variety of people, and they at least understand parts of it, and so that’s fun.”
Featured Image: University of Maryland paleontology professor Thomas Holtz is photographed in Montana in 2013. Photo from the University of Maryland Geology Department.