The long-running scientific debate may finally be coming to an end. A new study involving Ashley Poust of the University of Nebraska State Museum provides strong evidence that: nano tyrantIt is often described as a smaller version of . tyrannosaurus rexwhich was actually a real different species.
A research team led by Princeton University’s Christopher Griffin focused on the original fossil Nanotyrannus skull, housed at the Cleveland Museum of Natural History. To determine the animal’s age at death, the researchers examined a little-studied bone known as the ceratobranchial or hyoid bone that had been preserved with the skull.
The researchers used bone histology, the study of the microstructure of fossilized bones, to analyze this tiny throat bone and identify growth patterns that indicate the animal had reached or was close to full maturity. This discovery is important because it shows that the specimen is not a young Tyrannosaurus rex that is still growing.
These findings show that science.
“Compared to Tyrannosaurus, the hyoid bone of this small-bodied carnivore showed a growth pattern that suggests it is at or near maturity,” said Poust, Voorhees Endowed Curator of Vertebrate Paleontology. “This gives us confidence that the animal will clearly keep its name Nanotyrannus. tyrannosaurus rex. ”
much smaller predator
What the estimates suggest nano tyrant Reaches a length of about 18 feet, much smaller than an adult’s body tyrannosauruswhich can exceed 40 feet. This size difference supports the idea that it was not simply a young stage of a large species.
Fossils with a complicated history
of nano tyrant The skull was first discovered in 1942 and was initially classified as a Gorgosaurus. In 1988, further research led scientists to change its name. Nanotyrannus lansensis. However, many researchers later claimed that it was actually a juvenile tyrannosaurusfueled decades of debate.
New discoveries challenge long-held assumptions.
“The general consensus at the time was that nano tyrant The holotype skull expressed immaturity tyrannosaurus rex“Our predictions were simply in line with that consensus, but when we sampled the hyoid bone and saw features strongly indicative of maturation, we knew we needed to look at that idea with more skepticism,” said Griffin, an assistant professor of geosciences at Princeton University.
A new way to study dinosaur growth
To strengthen their conclusions, Puust compared hyoid bones of various species, including dinosaur relatives (ostriches, crocodiles, and lizards) and other fossil specimens. This approach has not previously been applied to dinosaur fossils, and could open up new ways to study fragmented fossils.
“Our ability to learn about animals’ past lives is slowly expanding,” Paust says. “It was exciting to show that growth signals are highly conserved throughout the body. Perhaps this will be a small wedge to start investigating it in different ways.”
Paust said he did not expect the hyoid bone to be such a reliable indicator of age. Traditionally, scientists have relied on large bones such as ribs and femurs for this type of analysis, but the results suggest that the hyoid bone may be useful as well.
The debate is likely to be resolved, but new questions have emerged
The question of whether nano tyrant The problems that existed as a separate species now seem to have largely been resolved. This study follows another recent paper. nature We also considered the possibility nano tyrant The fossil was discovered in Montana and is currently housed at the North Carolina Museum of Natural Science.
“We studied the holotype specimen because it is the only fossil, or other specimen, that officially defines the species. Nanotyrannus lansensis “This specimen is referred to by this one specimen that retains the species name,” Griffin said. “As this specimen is mature, this clearly shows that Nanotyrannus is different from other specimens.” tyrannosaurus. ”
Impact of dinosaurs on the ecosystem
One debate may be coming to an end, but the discovery raises new questions about how prehistoric ecosystems were organized. if nano tyrant and tyrannosaurus Their existence at the same time suggests that multiple large predators shared the same environment.
“This leaves at least two carnivores of different sizes in the same environment, which has major implications for ecology and the extinction of dinosaurs,” Paust said. “Learning more about what existed can tell us how large the fossil record is and how species change over time. And it’s important to understand the complexity of ecosystems.”
