A prehistoric toothed bird that lived 67 million years ago is turning the bird tree of life on its head. The bird — named Janavis finalidens — shares crucial features with its modern cousins such as chickens and ducks, which is forcing a rethink about bird evolution1.

A stone-encased fossil was plucked from a Belgian quarry two decades ago2. It was found in a geological layer that dates back to the Late Cretaceous period (100.5 million to 66 million years ago), just before the mass extinction event that wiped out all non-avian dinosaurs. At the time of the fossil’s discovery, it seemed to comprise just a handful of bones from the spine, wings, shoulders and legs.

Daniel Field, a palaeontologist at the University of Cambridge, UK, and his colleagues re-examined the bones using micro-computed tomography to better investigate the creature’s anatomy. From those scans, they were able to describe the specimen as a new species of ancient bird that shared a common ancestor with modern birds. When it lived, Janavis finalidens would have been similar in size to a grey heron. The study is published in Nature today.

The team also discovered that one of the bones, previously thought to be a shoulder bone, was actually from the skull — a bone called the pterygoid. “It is from a very interesting part of the skull, from the bony palate of the bird,” says Field. The bony palate has crucial features that researchers use to group birds, both living and extinct.

A prehistoric toothed bird that lived 67 million years ago is turning the bird tree of life on its head. The bird — named Janavis finalidens — shares crucial features with its modern cousins such as chickens and ducks, which is forcing a rethink about bird evolution1.

A stone-encased fossil was plucked from a Belgian quarry two decades ago2. It was found in a geological layer that dates back to the Late Cretaceous period (100.5 million to 66 million years ago), just before the mass extinction event that wiped out all non-avian dinosaurs. At the time of the fossil’s discovery, it seemed to comprise just a handful of bones from the spine, wings, shoulders and legs.

Daniel Field, a palaeontologist at the University of Cambridge, UK, and his colleagues re-examined the bones using micro-computed tomography to better investigate the creature’s anatomy. From those scans, they were able to describe the specimen as a new species of ancient bird that shared a common ancestor with modern birds. When it lived, Janavis finalidens would have been similar in size to a grey heron. The study is published in Nature today.

The team also discovered that one of the bones, previously thought to be a shoulder bone, was actually from the skull — a bone called the pterygoid. “It is from a very interesting part of the skull, from the bony palate of the bird,” says Field. The bony palate has crucial features that researchers use to group birds, both living and extinct.