What did dinosaur meat taste like? A trip to Kentucky Fried Dinosaur, or a mouthful of Dinosaur McNuggets can answer that question!" So reads the closing line of a chapter on the origin of birds in a widely used palaeontology textbook.¹ To the authors of this text, as indeed to most contemporary vertebrate palaeontologists, birds didn’t simply descend from dinosaurs - birds are dinosaurs. All the others may have become extinct 65 million years ago, but one dinosaur group survives and it dominates our skies. This view has become so well accepted in scientific circles, and is so often repeated in the popular media, that to deny it almost amounts to heresy.

The idea that birds and reptiles are closely related is not a new one. Ever since Darwin, similarities between modern birds and reptiles (such as the possession of scales and the laying of shelled eggs) prompted speculation that these groups shared a common evolutionary ancestor. Then, in 1861, the first specimen of the famous Archaeopteryx ("ancient wing") was discovered in a limestone quarry in Bavaria. It seemed to be a curious mosaic of bird-like and reptile-like characteristics. For many, this creature was - and is - a powerful confirmation of large-scale evolutionary change.

Subsequently, debate has raged in the evolutionist community about which group of reptiles is most closely related to birds. Several ancestral groups have been suggested, including crocodilians and archosaurs. The "accepted" view today is that the birds are derived from theropod dinosaurs, in particular a group known as dromaeosaurids.² These were lightweight agile meat-eaters equipped with a massive claw on one of the toes on each foot. Recently, a succession of fossil finds from lake sediments of the Yixian Formation in Liaoning Province, northeastern China, has been claimed to support the theropod ancestry of birds. Beneath banner headlines such as "Feathered dinosaurs lift theory of birds’ origin"³ the newspapers have regaled us with the strange names of these newly discovered fossil creatures: Sinosauropteryx, Protarchaeopteryx, Caudipteryx, Beipiaosaurus, Archaeoraptor. Even stranger, though, are the descriptions of these animals. Take Sinornithosaurus, for instance, described in a recent edition of Nature.⁴ It is classified by its discoverers as a dromaeosaurid dinosaur, yet from the neck down it is said to be "remarkably similar to early birds". The shoulder girdle appears to be adapted for powered, flapping flight. It bears "integumentary filaments" on its body, interpreted as primitive feathers. An odd creature indeed! What are creationists to make of these discoveries?

In one sense it is too early to draw firm conclusions. The rate at which these new fossils are being discovered far outpaces the rate at which detailed scientific descriptions and analyses can be published. It will probably be years before a clear picture is built up. In the meantime, informed scepticism about the interpretation of these finds is in order. Experience cautions against a too ready acceptance of everything we read about these "feathered dinosaurs". One of the earlier fossil finds, Sinosauropteryx, was also claimed to have downy "proto-feathers", but these turned out to be simple fibres lacking the branching pattern of modern feathers.⁵ The function of these filaments is currently a mystery. It is possible that they were a support structure for some kind of crest, or a collagen structure in the skin to maintain body shape.⁶ If so, they are not accurately described as "proto-feathers". By contrast, Protarchaeopteryx and Caudipteryx are said to possess feathers identical to those of modern non-flying birds. Maybe that is all these creatures are - extinct flightless birds, unrelated to dinosaurs. Certainly the middle Early Cretaceous age of the Liaoning lake sediments⁷ makes these fossils too young to be direct "pre-bird" ancestors. Despite its name, Protarchaeopteryx is later than Archaeopteryx, the famous fossil from Late Jurassic Germany - and Archaeopteryx, certainly, was a true bird. For this reason, advocates of the theropod hypothesis view this region as a "refugium" - an isolated area in which relict species survived much longer than elsewhere.

The theropod hypothesis of bird origins may be the current consensus, but not all evolutionists are convinced by it. Ornithologist Alan Feduccia of the University of North Carolina believes that the similarities between birds and theropods have been overstated. Take, for instance, the supposed homologies (inherited similarities) between the forelimbs of birds and theropods. Both have a three-fingered "hand". However, embryological studies⁸ indicate that the bird "hand" consists of digits II-III-IV. Theropods possessed digits I-II-III. This is clearly contrary to the view that birds were derived from theropods. Another study looked at the structure of the lungs.⁹ An examination of Sinosauropteryx revealed that in theropods, as in modern-day crocodiles, the thoracic cavity is completely separated from the abdominal cavity by the diaphragm. Birds, by contrast, have no such separation. This is significant because it is difficult to imagine a transition from the theropod-like arrangement to the bird-like arrangement that would not be debilitating to the creature and thus selected against. Perhaps the most crucial problem for the theropod hypothesis is that theropods are saurischian ("lizard-hipped") dinosaurs. If the theory of evolution is true birds ought to have evolved from the ornithischian ("bird-hipped") dinosaurs. This anatomical difference is so fundamental that it forms the basis for all dinosaur phylogenies (family trees), yet it is so often ignored in discussions of the evolutionary ancestry of birds. Much else could be said on this subject of theropod and bird relationships (or lack of them) and we are planning a full article in Origins to discuss the issues further.

Scripture teaches us that birds had a separate origin from other animals.¹⁰ We are on firmer ground if we build our scientific hypotheses on biblical revelation rather than "shoe-horning" the data to fit evolution.

Paul Garner (December 1999)

References

1. Fastovsky D.E. and Weishampel D.B. The evolution and extinction of the dinosaurs, Cambridge University Press, 1996, 321.
2. Padian K. and Chiappe L.M. The origin of birds and their flight. Scientific American, February 1998, 28-37.
3. Hawkes N. Feathered dinosaurs lift theory of birds’ origin. The Times, Wednesday 24 June 1998, 1.
4. X. Xu., Xiao-Lin W, Xiao-Chun W. A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China. Nature, 16 September 1999, Volume 401, 262-266.
5. Feathered fallacy. New Scientist, 12 April 1997, 13.
6. Poling J. Sinosauropteryx feathers. Available on the internet at http://www.dinosauria.com/jdp/archie/sinonews.htm. Accessed on 13 February 1998.
7. Swisher C.C., Yuan-Qing W., Xiao-Lin W., X Xu. and Yuan W. Cretaceous age for the feathered dinosaurs of Liaoning, China. Nature, 1 July 1999, Volume 400, 58-61.
8. Burke A.C. and Feduccia A. Developmental patterns and the identification of homologies in the avian hand. Science, 24 October 1997, Volume 278, 666-668.
9. Ruben J.A., Jones T.D., Geist N.R. and Hillenius W.J. Lung structure and ventilation in theropod dinosaurs and early birds. Science, 14 November 1997, Volume 278, 1267-1270.
10. Genesis 1:20-21.

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