Class of 2018: Budding 'rockhound' journeys forward by looking back
Alex Bradley says he’s always been a rockhound.
As a kid growing up in Alaska, Bradley loved finding things outside. Some of his earliest memories include picking up pebbles on a local playground.
But his passion for natural treasures didn’t stop at childhood. Instead, Bradley’s hunting eventually led him to Virginia Tech, where he found a home in Derring Hall. There he unpacked and cleaned fossils brought to Blacksburg from various locations around the globe, from Arizona and New Mexico to Tanzania and Zimbabwe.
Bradley, a soon-to-be graduate in geosciences, found this scientific home by taking an introductory geology course, Earth’s Dynamic System, with Sterling Nesbitt, an expert vertebrate paleontologist in geosciences in the university’s College of Science and research affiliate in the Global Change Center. After Nesbitt learned of Bradley's interests, he invited him to his lab, where Bradley quickly became enamored with prying apart packing material and cleaning specimens, because doing so meant learning what was inside.
Bradley’s curiosity and skillset grew so much that he was able to identify two tiny specimens Nesbitt brought to campus from the Cambridge Museum of Zoology in England. The specimens, Bradley found, are small pieces of lower jawbone, each about the length of a quarter, which likely belonged to a lizard-like reptile that lived about 240 million years ago.
In 2013, a reptile from the same group of egg-laying reptiles and birds, called sauropsids, was identified and named based on a skull found in the Ruhuhu Basin of southern Tanzania in 1933. That same year, on the same expedition, the two pieces of jawbone were found in the same geographical location as the skull, though from a different individual.
According to Bradley’s research, these jawbone specimens belong to a reptile of the same species that was likely more than twice the size of the initial individual. They now represent only the second specimen ever found of this reptile, named Ruhuhuaria reiszi (Roo-hoo-hoo-AHR’-ee-uh reye-zeye).
“A mouthful,” Bradley joked. “But it’s a big question to look around and ask, how did we get here? It all starts with finding fossils, which is treasure hunting because you know you’re finding something on the ground that’s scientifically valuable.”
The jawbone specimens Bradley identified also provide evidence of this reptile’s diet, as they contain three fully intact back teeth — evidence not found in the skull. The teeth are shaped more like chisels than like sharp points, indicating these reptiles may have eaten more plants than animals.
The findings, published recently in the Journal of Vertebrate Paleontology, were part of a memoir project led by Nesbitt, who has now spent many years studying Tanzanian fauna. The now-published memoir showcases fossil finds and climatic evolution in Tanzanian and Zambian basins dating to around 200 to 250 million years ago in the Triassic Period.
Just prior to the Triassic, the end of the Permian Period experienced a ‘Great Dying,’ a significant environmental change that wiped out over 90 percent of Earth’s animals, Bradley explained. Scientists aren’t exactly sure what happened, but evidence shows large volcanoes erupted. This, in turn, could have led to excessive fire and gas, including methane, potentially causing a greenhouse-like effect in which the planet warmed beyond habitable for most organisms.
But the reptiles were resilient, though finding evidence from this time in Earth’s history is rare. So far, evidence suggests Bradley’s reptile may have been part of a group that was one of only a few that survived the planet’s conditions during the end Permian extinction, signaling they were able to adapt to the drastic environmental change. At least, explained Bradley, this was until more recently, around 66 million years ago, when these reptiles died out with most of the large dinosaurs at the end of the Cretaceous Period. Theropod dinosaurs, which look like smaller feathered velociraptors in the movie Jurassic Park, survived the asteroid that marked this period’s extinction. Today we know them as birds.
Currently Bradley is working with the oldest known set of chest bones, or sternal plates, from a small dinosaur that lived about 210 million years ago. He’s studying them closely to characterize the tiny ridges and subtle crevices to learn clues about dinosaur anatomy and the origin of these bones in living birds.
“If you’ve ever carved a Thanksgiving turkey and found the sternum, that’s what it looked like back in the Triassic. Their pectoral musculature was not as prominent as in birds, as they didn’t have a single sternum that later helped them evolve into flight," Bradley said.
"Turkeys are fun because you can look at the features that make it a dinosaur. You can be a big old nerd about it,” he added.
Bradley’s interest in anatomy has now become a hobby — a hobby he finds so enthralling that he recently cleaned the bones of a dead opossum found on his parents’ 60-acre farm so he could carry them in his backpack.
“We’re studying ancient life, and nowadays we can take what we know about life and apply it to the past. So if you want to study something that isn’t alive today, then you can study living animals,” said Bradley. “You can do dissections and analytical techniques to understand their physiology and behavior. A lot of people look at paleontology as studying living things and then applying what they learn to dead things.”
In the fall, Bradley will head to the University of Iowa for graduate school to study paleontology, where he will merge his two interests in biology and geology to ultimately shed light on the history of life on Earth and knowledge about evolution and the planet’s surface processes, such as geologic time, climate changes, and ecology. He’s especially excited about how the timing and relationships of past events explain Earth's changes, and how events such as climate and temperature changes could impact ecosystems now and in the future.