O. Archaeopteryx fossil

When the fossil was discovered in Germany in 1861, it caused a lot of confusion. No birds were known from so far back. Some people even thought it wasn’t a bird, but an angel.

Richard Owen, this Museum’s first superintendent, knew there was something extraordinary about it. Even he didn’t realise just how remarkable it was.

Archaeopteryx was not like modern birds. It had feathers like a bird, but teeth, claws and a bony tail like a dinosaur.

Owen was world-famous for identifying animals. He classified Archaeopteryx as a bird, rejecting a suggestion that it might be a link to reptiles.

The curious fossil was discovered just a few years after Charles Darwin published his controversial theory of evolution.

Darwin’s strongest supporter, Thomas Henry Huxley, first suggested Archaeopteryx showed an evolutionary link between dinosaurs and birds in 1868. And so the half-bird half-dinosaur became central to the evolution debate. Until then, no intermediate forms between living animals and their supposed ancestors had been found.

After scrutinising Archaeopteryx, scientists decided it was a bird – the earliest discovered.

We are still learning about bird evolution from this fossil. The shape and arrangement of the wing feathers show similar adaptations for flight to modern birds.

Museum scientist Angela Milner led an international team that found further evidence Archaeopteryx could fly by studying its brain.

Bird brains fit very tightly in the skull so an imprint is left on the inside of the bones.

Of the 10 Archaeopteryx specimens known to science, this is the only one whose brain imprint has been fully preserved. From it, scientists built a 3D reconstruction of the brain, which shows Archaeopteryx had the sight, balance and co-ordination necessary for flight.

Fossils found more recently in China also have feathers, but ones adapted for warmth and display, not flight.

They are definitely dinosaurs and the closest relatives to Archaeopteryx yet discovered, so they throw into question whether Archaeopteryx was a bird after all.

On balance, the evidence still places Archaeopteryx with the birds, but only new discoveries will clarify the evolution of the bird family tree.

In 2011 this fossil was elevated as the type, the one all others are compared to. Before this, the official representative was a single fossil feather. Despite being discovered first, we can’t prove it belonged to Archaeopteryx.

This specimen’s complete skeleton and feathers provide a more reliable reference for research on early birds.

See where Archaeopteryx fits in the timeline of life in From the Beginning, in the Red Zone.