A fossil from China that’s 150 million years old may be the world’s earliest known bird. The discovery shows that the short tails characteristic of modern birds evolved much earlier than previously thought.

Birds evolved from theropods, a group of dinosaurs that included tyrannosaurs and velociraptors, during the Jurassic period. Archaeopteryx, discovered in 1961, has long been considered one of the earliest birds in the fossil record. But its position on the evolutionary tree is debated because, despite having feathered wings, Archaeopteryx is more similar to non-avian theropods in having a long, reptilian tail.

The new fossil was found in Zhenghe County in Fujian province in November 2023 and has been given the species name Baminornis zhenghensis. Only the trunk, forelimb, pelvis and part of the hindlimb are preserved.

Baminornis lived at the same time as Archaeopteryx but it has a short tail like those of modern birds, pushing back the date of this evolutionary innovation by 20 million years.