A new study claims birds started flying far earlier than was previously thought, writes Dick Ahlstrom
It might have had feathers but could it fly? Scientists at London's Natural History Museum now believe that yes the most ancient bird known, 145 million-year-old Archaeopteryx, could fly and had a brain designed for flight.
The animal had a brain similar to a modern sparrow, eagle or parrot, according to a team led by Dr Angela Milner, a palaeontologist at the Natural History Museum.
The group used advanced X-ray computed tomography (CT) scans, a technology more regularly used for medical diagnosis, to study the inner structures of the Archaeopteryx brain case and inner ear.
Details of their findings are reported this morning in the journal, Nature. They believe the evidence is sufficient to prove that birds started flying far earlier than scientists previously thought. The museum used its own Archaeopteryx fossil, sending the 20mm-long braincase of this chicken-sized animal to the University of Texas at Austin for CT scanning. This data was then brought back to the Museum where Milner and her group created computerised 3-D reconstructions to investigate the anatomy of the brain in detail.
The first Archaeopteryx lithographica fossil was dug out of the earth in Germany in 1861. The small meat-eating bird had feathers but also dinosaur-like features including sharp teeth and clawed hands. Its arrival on the scene immediately sparked a debate on the link between dinosaurs and birds, something that remains a controversial subject to this day.
Using the CT data and advanced computers, the team was able to determine the brain's shape, size and volume and create a reconstruction of the animal's inner ear for the first time. The studies showed that the Archaeopteryx brain and inner ear had very bird-like proportions. Measurements taken of the organs of balance inside the ear, known as semi-circular canals, proved to be very close in size to those of today's birds.
Milner and her group noted the dominance of parts of the brain associated with vision, arguing that the fossil brain suggested a well-developed sense of vision and a highly developed spatial sense. Both are requisites for modern bird flight.
This new evidence suggests that Archaeopteryx was already well equipped for flight, but also drums up the debate of when ancient birds first took flight. If Archaeopteryx was fully capable of flight and not just a land-based meat eater with feathers then considerable evolution and adaptation must have preceded its appearance in the fossil record, Milner argues.
"If flight was this advanced by the time Archaeopteryx was around, then were birds actually flying millions of years earlier than we'd previously thought?
"As yet we have no earlier fossils to help us piece together this fascinating evolutionary story and this study has shown how much there is still to discover about when and how bird flight began," says Milner.
The Museum's Archaeopteryx fossil is one of only seven in the world, and it is the most valuable single fossil in its collection. Due to its fragility, value and constant demand by visiting scientists from around the world, Archaeopteryx is usually kept in environmentally controlled conditions where it is accessible for research study.