A new dinosaur species named Tyrannosaurus mcraeensis represents a significant milestone in understanding the species’ evolution, and a local educator played a role in its discovery.
Assistant teaching professor of biology at Penn State Lehigh Valley D. Edward Malinzak is a member of the research team that identified the specimen, named it and co-authored a study about the findings that was recently published in the journal Scientific Reports.
Led by Sebastian Dalman, a doctoral candidate at Montana State University, the study concluded that Tyrannosaurus mcraeensis is a separate species of dinosaur that lived millions of years before T. rex and was essentially an ancestor of the “tyrant lizard king.”
The specimen on which the finding is based was discovered by a group of canoeists along the edge of a lake in Elephant Butte, New Mexico, in the early 1980s. It was later donated to the New Mexico Museum of Natural History and Science (NMMNH), whose field crew found more bones from the same prehistoric predator in the late 1990s.
A nearly complete lower jaw, the Tyrannosaurus mcraeensis specimen is believed to be around 74 million years old, based on radioisotopic dating. By comparison, Tyrannosaurus rex lived between 68 to 66 million years ago.
“It was referred to (as) T. rex first; however, recent radioisotopic dating of the stratigraphic unit in the Hall Lake Formation in which Tyrannosaurus mcraeensis was found show an age of 74 million years,” Dalman said. “It’s really an ancestor of the T. rex in North America. It was believed the T. rex came from Asia, but it looks like they went from North America to Asia and not the other way.”
Malinzak, who joined the team in 2019, said researching the specimen was very much a group effort.
“I met up with (Dalman) in South Dakota and started talking, and I asked if anyone was doing paleobiogeographic work,” he said, adding that he later connected with the team from the NMMNH and became part of the project. “People thought it was T. rex all this time, but if you look at everything in the whole picture, it doesn’t really come close. With the time gap, there is a temporal difference between the species. It gives us some extremely important information–it’s the origin story for T. rex.”
Malinzak’s contributions to the work focused on comparing the specimen with closely related tyrannosaurs to better understand the way in which the jaw differed from other tyrannosaur species.
“I also contributed to the discussion of the specimen in terms of paleobiogeography and evolutionary implications,” said Malinzak, who has also conducted work related to Laramidia, an ancient continent which comprised the western half of modern-day North America. “Through several back-and-forth conversations regarding various aspects (of the research process), we were able to synthesize a hypothesis as to the evolutionary implications this specimen/taxon might have in our understanding of…evolutionary history and specifically the evolution of Tyrannosaurus.”
This local news story was reported with generative AI assistance.
