No Flight in Archaeopteryx

The new study by Dominguez Alonso et al. on the Archaeopteryx brain is a very fine piece of work. The brain is very bird-like, though as you might imagine it is primitive bird-like. But no matter what the authors hint, or the journalists trumpet, this study provides no proof that Archaeopteryx flew (and Witmer says that too in his commentary). The study does show clearly that Archaeopteryx is close to the origin of flight.

I've said before in the various editions of History of Life that Archaeopteryx flew very badly at best, and probably didn't fly at all in the sense we associate with most living birds. Jere Lipps and I originally proposed that more than 20 years ago. Does the new study change my/our view? No. But I need to justify that blunt statement.

Everyone agrees that two things are needed BEFORE flight: the anatomy (hardware), and the instrumentation (brain/software). The new study provides sufficient information for us to accept that Archaeopteryx had the software. I still argue that Archaeopteryx lacked the hardware.

Even humans have the software for flight. Just strap on a hang glider on a reckless human, or place an athlete inside the Gossamer Albatross. The add-ons provide the necessary hardware, and the human very quickly learns to use pre-existing vision/balance/co-ordination and can fly effectively. However, all that sensory capability is useless for flight without the hardware. And I think that's true for Archaeopteryx as well.

I certainly wouldn't be surprised if many feathered theropods turned out to have Archaeopteryx-like brains: it wouldn't mean that they flew.

Here are the arguments that suggest Archaeopteryx lacked the necessary hardware. None is fatal in itself, but together they say (to me) that Archaeopteryx is pre-flight. Please let me know if I am using arguments that have been superseded. The concept of a flying Archaeopteryx is attractive. I expect I speak for most paleontology instructors when I say that it would make the evolutionary story cleaner and simpler than the reality. I'd love to be converted, but there has to be evidence.

1. The glenoid of Archaeopteryx is set at such an angle that the arm could not have been raised high enough for an effective downstroke.
2. The shoulder lacks the triosseus canal, showing that the pulley system of the supracoracoideus that gives the rapid upstroke of the wing in modern bird flight was not available to Archaeopteryx. (In passing, that's why WAIR does not work either!)
3. The furcula is robust (non-flexible), so could not have had the function that it has in advanced flying birds, to space the shoulders in active flapping, and to help respiratory flow at high exercise levels.
4. There are claws on the ends of the fingers where modern birds have long primaries. This must detract from potential lift and acceleration.
5. The tail is long and bony, and the tail feathers have the worst possible arrangement in terms of poor lift and high drag.
6. The pelvis lacks the strength and shape that gives flying birds the ability to land hard.
7. There is no sternum to provide the strong basis for flight muscles that it is in later birds.

Obviously, birds were flying well by early Cretaceous times, as seen from many of the Jehol specimens. What I'm arguing is that Archaeopteryx isn't quite there yet in the late Jurassic.

Is this interpretation published? Yes, several times. See this selection of published pieces

Page composed by RC, August 7, 2004

Updated March 10, 2005

Links checked October 3, 2005