27 December 2008
The "Jesus Christ dinosaur hypothesis"
The video above is from National Geographic, documenting the remarkable ability of the basilisk to walk on water (that's why it is colloquially known as the "Jesus Christ" lizard).
Understanding how the basilisk accomplishes this raises the question as to whether this was the mode of locomotion of the dinosaur ancestors of modern birds. All of the fossils of the primitive Archaeopteryx have been found in what 150 million years ago was an archipelago of coral islands. There is no tree pollen in the deposits that hold the Archaeopteryx fossils, suggesting that they did not glide from trees. Also, they were very small - the size of the basilisk.
Perhaps Archaeopteryx was a shore bird running across shallow waters, and the feathered upper limbs were developed to enhance this performance; after several millennia they could have evolved into proper wings with aerodynamic lift. Anyone who has ever spent time fishing or at a lakeshore or seashore has certainly seen modern seabirds run across the surface before attaining enough velocity to allow liftoff.
This "ground up" hypothesis for the origin of bird flight was apparently first proposed in 2000; other paleontologists and biologists disagree and favor a "trees down" development from gliding to flapping. The argument won't be settled soon - nor need it be. It's just interesting to ponder...