A team of experts has discovered a new species of tyrannosaur, Khankhuuluu mongoliensis, which is believed to be the immediate ancestor of the family called tyrannosaurs. The 86-million-year-old skeleton was unearthed in Mongolia and found to have characteristics of both typical and atypical tyrannosaurs.
Unlike its previously identified predecessor, Alectrosaurus olseni, Khankhuuluu belonged to a new species with more modest size. It measured about four meters in length and weighed around 750 kilograms, making it significantly smaller than the massive T rex predators that evolved later.
According to Jared Voris, the first author of the research, humans would have been an easy prey for Khankhuuluu if they had coexisted. However, the discovery also sheds light on the evolution and migration patterns of tyrannosaurs. The team found that some small, long-nosed tyrannosaurs called Alioramus are more closely related to giant forms like T rex and Tarbosaurus.
By analyzing computer models incorporating the new family tree and known species, the researchers were able to reconstruct the migration history of tyrannosaurs across land bridges between Asia and North America. They discovered that such movements were less sporadic than previously thought, revealing a complex pattern of evolution and dispersal.
Source: https://www.theguardian.com/science/2025/jun/11/tyrannosaurs-new-species-fossils-mongolia