Archaeopteryx fossil

 

 

 Archaeopteryx lithographica fossil, around 147 million years old.

Archaeopteryx is the earliest known bird and the Natural History Museum cares for the first skeleton specimen ever found. This spectacular fossil helped prove that modern birds evolved from dinosaurs and was the first example providing support for Darwin's theory of evolution. It is the most valuable fossil in the Museum's collection.

Sketch by Joseph Dinkel from Richard Owen’s paper on Archaeopteryx, 1863.

Mysterious discovery

The fossil caused a lot of confusion when it was discovered in Germany in 1861. It had feathers like a bird, but teeth, claws and a bony tail like a dinosaur.
Richard Owen, the Museum’s first superintendent, knew there was something extraordinary about it. World-famous for his skill in identifying animals, he classified Archaeopteryx as a bird. No birds were known from so far back in time.
But Owen failed to realise just how remarkable Archaeopteryx was.

Evidence for evolution

The curious fossil was discovered just a few years after Charles Darwin published his controversial theory of evolution.
In 1868, Darwin’s strongest supporter, Thomas Henry Huxley, suggested Archaeopteryx showed an evolutionary link between dinosaurs and birds. Until then, no intermediate forms between living animals and their supposed ancestors had been found. The half-bird half-dinosaur became central to the evolution debate.

Illustration of how Archaeopteryx might have looked. © DEA Picture Library / De Agostini / Getty Images

Capable of flight

The shape and arrangement of the wing feathers of Archaeopteryx show adaptations for flight similar 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 skull and brain imprint could be studied. The back part of the skull was at the edge of the specimen block, so it could be removed and put in a CT scanner. Scientists used the scan data to build a 3D reconstruction of the brain. It shows Archaeopteryx had the sight, balance and coordination necessary for flight.

Fuzzy raptor, Sinornithosaurus, a flightless feathered dinosaur that lived in China 124-122 million years ago. © John Sibbick / Natural History Museum, London

Dinosaur or bird?

Fossils found more recently in China (such as Sinornithosaurus and Xiaotingia) also have feathers, but ones adapted for warmth and display, not flight.
They are the closest relatives to Archaeopteryx yet discovered but are definitely dinosaurs, so they throw into question whether Archaeopteryx was a bird after all. Perhaps it was one of many early flying experiments rather than the direct ancestor of modern birds.
On balance, the evidence still places Archaeopteryx with the birds, in the group Avialae. New discoveries will clarify the evolution of the bird family tree.

Official representative of the species

Fossil feather that was the original type specimen for Archaeopteryx until 2011. © O Louis Mazzatenta / National Geographic / Getty Images

Originally, a single fossil feather was the official representative of the species Archaeopteryx lithographica. But despite being discovered first, the feather cannot be proved to belong to Archaeopteryx.
The complete skeleton and feathers of the fossil looked after by the Museum provide a more reliable reference. In 2011, it replaced the fossil feather as the type specimen. So it is now the one all others are compared to.