Palaeocursornis

Palaeocursornis was originally thought to be a bird, but later scientists determined it was a pterosaur, a flying reptile.21

Its name means 'ancient running bird', even though it was not a bird and not a runner. It flew instead.2

The only known fossil of Palaeocursornis is a partial thigh bone (femur). That makes it very hard to know exactly what it looked like.21

Some scientists think Palaeocursornis might not be a valid species at all. They call it a nomen dubium, which means a 'doubtful name'.21

The fossil was found in a bauxite mine in Romania, inside a lens of rock that was once part of an ancient cave system.1

The rock that held Palaeocursornis is between 143.1 and 137.05 million years old, from the Berriasian stage of the Early Cretaceous.2