Fossils found in 1970s are most recent ancestor of tyrannosaurs, scientists say

Researchers identify new species named Khankhuuluu mongoliensis from skeletons unearthed in Mongolia

Tyrannosaurs might evoke images of serrated teeth, massive bodies and powerful tails, but their most recent ancestor yet discovered was a slender, fleet-footed beast of rather more modest size.

Experts say the new species – identified from two partial skeletons – helps fill a gap in the fossil record between the small, early ancestors of tyrannosaurs and the huge predators that evolved later.

“They’re almost the immediate ancestor of the family called that we call tyrannosaurs,” said Dr Darla Zelenitsky, co-author of the study at the University of Calgary.

Writing in the journal Nature, Zelenitsky and colleagues report how they re-examined fossils unearthed in Mongolia in the early 1970s, and now held at the Institute of Paleontology of the Mongolian Academy of Sciences.