Baminornis

Baminornis had a fused tail bone called a pygostyle, which is a feature of modern birds and was very rare among Jurassic birds.21

It lived around 150 million years ago, during the Late Jurassic period, in a swampy environment.1

Baminornis was very small, weighing only about 130 to 300 grams, similar to a modern robin or sparrow.1

Its shoulder bones were not fused together, which may have helped it fly better than Archaeopteryx.1

The fossil of Baminornis was found in the Zhenghe Fauna, a site that also contained turtles, fish, and other early birds.1

Some scientists think the pygostyle of Baminornis might actually be part of its hip bone, not a tail bone, so its tail length is still debated.1