Researchers have long debated the classification of a dinosaur unearthed in the 1940s: was it a juvenile Tyrannosaurus rex or a separate species? This question has intrigued paleontologists for decades, primarily due to the limited evidence available at the time.
Initially, scientists only had a tyrannosaur skull, which complicated efforts to determine whether it belonged to a young or adult dinosaur. The discovery of another skull and skeleton, colloquially referred to as “Jane,” further fueled the discussion but did not provide definitive answers. However, a recent study suggests a breakthrough in understanding this mystery.
A skeleton fully excavated in 2006 in Montana has been analyzed, leading researchers to believe they have identified the dinosaur as a separate species rather than a juvenile T. rex. “This discovery rewrites decades of research on Earth”s most famous predator,” stated Lindsay Zanno, a co-author of the study affiliated with the North Carolina Museum of Natural Sciences and North Carolina State University.
Growth rings in the bones from the Hell Creek Formation in Montana indicated that the newly classified dinosaur was an adult, approximately half the size of a fully grown T. rex. By comparing growth patterns to those of other reptiles, like crocodiles, the researchers concluded that significant differences in skull structure, nerve patterns, and sinus formations could not be attributed solely to puberty.
This evidence points to a dinosaur that is a distant relative of T. rex, known as Nanotyrannus lancensis, as detailed in a study published in the journal Nature. Holly Woodward, a fossil bone expert from Oklahoma State University, noted that there is now “more support and evidence than ever” for the existence of this relative, though she remains skeptical about classifying other specimens like Jane as new species.
Other experts have echoed this sentiment, suggesting that while the new skeleton is indeed an adult, it could represent a sister species to T. rex rather than a mere offshoot. Vertebrate paleontologist Thomas Carr of Carthage College has highlighted similarities between the skull shapes that complicate the classification process.
The resolution of this classification debate is crucial for understanding the developmental stages of T. rex and its role as a dominant predator during the late Cretaceous period, approximately 67 million years ago. Additionally, it raises questions about whether T. rex was the primary predator of its time or if smaller yet formidable predators coexisted.
The newly discovered skeleton, dubbed “Dueling Dinosaurs” due to its intertwined bones with a Triceratops, is currently displayed at the North Carolina Museum of Natural Sciences.
