Remains of intermediate appear in a 40-million-year–long gap in tyrannosaur fossil record
A newly described species of tyrannosaur is small enough to look humans in the eye. Fossils of the new tyrannosaur, Xiongguanlong baimoensis, help fill in details about the evolution of the fearsome meat-eating dinosaurs. Xiongguanlong lived in what is now western China between 110 million and 120 million years ago, says Peter Makovicky, a paleontologist at The Field Museum in Chicago. That era lies well within a 40-million-year–long gap in the tyrannosaur fossil record, he and his colleagues note online April 21 in Proceedings of the Royal Society B.