A recent collaborative study by scientists from Oregon State, Purdue (at Fort Wayne), Johns-Hopkins, and the College of Charleston provides evidence that the once highly touted feathered dinosaur, Caudipteryx, was more likely a flightless bird.1
Caudipteryx first appeared in the scientific literature in 1998, when it was recovered from the Chaomidianzi Formation in the Liaoning province of China.2 At the time, the specimen (dated between 145 and 125 million years old) was described as a key transitional intermediate between the bipedal theropod dinosaurs and birds.3 This assertion was based on the fact that Caudipteryx possessed fully formed feathers identical to those found on birds.
This interpretation of the find has not been the only one, however.4 Many reasons have arisen for rejecting it. Some have been presented in previous issues of RTBs newsletter.5 The chief argument stems from what is known by paleontologists as the temporal paradox. Namely, Caudipteryx shows up in the fossil record after the oldest known bird, Archaeopteryx. 6-7
If Caudipteryx is not a transitional intermediate leading to birds, how then do scientists account for the similarities between birds and theropods? In a word, convergence. A widely observed phenomenon in the biological realm, convergence refers to the sharing of common anatomical characteristics by unrelated organisms. Since both birds and theropods are bipeds, it is not surprising that they would possess convergent, (i.e., similar) features. Recent research on the foot structure of birds and theropods supports the case for convergence over the case for shared ancestry.
Both organisms have three elongated digits that point forward, one digit that points backward, and one digit that is greatly diminished in size. Though these parallels initially suggest a bird-dinosaur ancestral relationship, careful analysis reveals fundamental differences. For example, theropods forward pointing digits are I-II-III, whereas birds are II-III-IV.8-9 Analysis of footprints shows significant differences between the two types of creatures with respect to digit I function, foot posture, and hindlimb excursion.10
To these differences in foot structure, scientists can now add the differences identified by Terry Jones and his research team.11-12 This group compared the center of mass and the hindlimb length to body-length ratio for flightless birds and bipedal dinosaurs. The differences were marked. The teams analysis also revealed significant differences in the bipedalism of theropods and flightless birds. When flightless birds walk, they leave their upper leg relatively stationary while swinging the lower leg (below the knee). This description fits Caudipteryx, too. By contrast, bipedal dinosaurs used their entire leg to walk.
Jones's analysis indicates that Caudipteryx is more likely a flightless bird that appeared on earth after Archaeopteryx. Caudipteryx can no longer be considered a dinosaur-bird transitional intermediate, nor does it appear that Caudipteryx is a feathered theropod that happens to possess convergent features with birds. The next step will be to determine if the other feathered theropods, such as Protarchaeopteryx, possessed bipedalism similar to that of flightless birds.
The evolutionary paradigm simply cannot explain the origin of birds. Meanwhile, the biblical account of bird origins found in Genesis 1:20-21 best matches the record of nature.