Earliest Bird Had Dino-Like Feet

The earliest birds had theropod dinosaur-like feet, according to a new study published in Science describing the tenth and best-preserved specimen of Archaeopteryx, the first known bird.

The new specimen provides important details about the feet and skull of these birds and strengthens the widely but not universally accepted argument that modern birds arose from theropod dinosaurs. The new magpie-sized specimen reveals that the bird could hyperextend its second toe, providing an additional similarity with the theropod dinosaurs proposed to be its closest relatives, the "deinonychosaurs."

Parts of the new specimen's exceptionally well-preserved skull also share notable similarities with those of theropods. Unlike modern birds, the first toe in this early bird was not reversed, Gerald Mayr and colleagues report in the 02 December 2005 issue of the journal Science.

Instead, the first toe pointed inward, similarly to the human thumb, indicating that the bird did not have a "perching foot." This detail shows that Archaeopteryx was less similar to modern birds than previously thought, according to the authors.

This bird, called the "Thermopolis Specimen," is from the Solnhofen limestone deposits of Bavaria, Germany and lived about 150 million years ago, during the Late Jurassic period. The authors note that, in addition to providing further evidence for the theropod ancestry of birds, these observations blur the distinction between archaeopterygids (the family that includes this early bird) and basal deinonychosaurs, a group of theropods with "fearsome claws," which includes Velociraptors.

2 December 2005