A dinosaur new to science, described as a cousin of Tyrannosaurus rex, has a mix of features from two major tyrannosaur subfamilies. The fossil's anatomy does not fit neatly into either group, according to researchers.
Tyrannosaurs are typically divided into two subfamilies, each with distinct body plans. The new specimen shows characteristics of both, suggesting that the evolutionary split between these groups was not as clear-cut as once believed.
The discovery complicates the story of how tyrannosaurs evolved, hinting that traits may have appeared independently or that the two lineages interbred. The researchers say the find upends current assumptions about the group's family tree.