ARCHAEOPTERYX AND THE CREATIONISTS
by Lenny Flank
(c) 1995
<Note: The following image links added by huecotanks.com; not part of Lenny Flank's original manuscript. The links were added because the photos referenced by Lenny had become "404" STC 20050806>
Artist depiction of Archaeopteryx
Lithograph #1 of Archaeopteryx fossil
Lithograph #2 of Archaeopteryx fossil
The example of the evolutionary transition from reptiles to birds, as represented by the fossil Archaeopteryx, is without a doubt the most famous in the world, and nearly every biology textbook that discusses evolution cites Archaeopteryx as an example. Six specimens of Archaeopteryx lithographica have been found, the first just two years after Darwin's "Origin of Species" was published. In appearence, the specimens resemble the skeletons of small therapod dinosaurs--it is only the unmistakable imprints of feathers surrounding the fossil bones which indicate that we are dealing with a bird (in fact, the resemblance is so close that one of the skeletons was misidentified for several decades as a small therapod, and another was misidentified as a pterodactyl--a mistake not corrected until someone noticed the faint impressions of feathers).
One almost could not ask for a better example of a transitional fossil than Archaeopteryx. It exhibits an unmistakeable mixture of reptilian and avian characteristics. A bird, of course, is defined by the presence of feathers. Flight feathers of Archaeopteryx are well-preserved, and are virtually indistinguishable from those of modern birds. They possess the central shaft and side barbules found in any songbird of today. The feathers are also a
symmetrical and are wider on the trailing edge than the front edge--an adaptation shown by flying birds but not by flightless birds such as penguins or ostriches. This indicates that Archaeopteryx was probably capable of flight (although the fossil lacks the large keeled breastbone which all modern birds use to attach their flight muscles, and the attachment points were themselves much smaller than in modern birds--thus it is possible that Archaeopteryx was only a glider and was not capable of powered flight). The large contour feathers are the only kind found on Archaeopteryx skeletons--no smaller downy feathers have been found, although these are possessed by all modern birds.
Apart from the feathers, however, Archaeopteryx exhibits a number of characteristics which are not birdlike at all, but are shared by the therapod dinosaurs--and some of these are found in no other group of animals. Among the dinosaurian characteristics exhibited by Archaeopteryx are: simple concave articulation points on the cervical vertebrae, rather than the elongated saddle-shaped articulation found in birds; vertebrae in the trunk region which are free and mobile, rather than fused together as in birds; the presence of gastralia, or abdominal ribs, which are found in reptiles and therapods but not in birds; a rib cage which lacks uncinate processes and does not articulate with the sternum, rather than the strutlike uncinates and sternum articulations found in all birds; a sacrum consisting of only 6 vertebrae, rather than the 11-23 found in birds; mobile joints in the bones of the elbow, wrist and fingers, rather than the fused joints found in birds; a shoulder socket that faces downward like a therapod's, rather than outward like a bird's; solid bones which lack pneumatic sacs, rather than the hollow air-permeated bones found in birds; and a long bony tail with free vertebrae, rather than the short fused pygostile found in birds;
The Archaeopteryx skull is also typically reptilian in structure, exhibiting: a number of openings or "fenestrae" in the skull, arranged as in therapod dinosaurs and not birds; a heavy but short quadratic bone which is inclined forward as in reptiles; a bend in the jawbones behind the tooth row; a long retro-articular process, which is found in reptiles but not in birds; a thin straight jugal bone as in reptiles; a preorbital bar separating the anteorbital fenestra and the eye socket (a reptilian characteristic); an occipital condyle and foramen magnum that are located above the dorsal end of the quadrate bone as in therapods, rather than below the quadrate as in all other birds; and a brain structure which exhibits elongated and slender cerebral hemispheres which do not overlap the midbrain (in birds, the cerebral hemispheres are heavy and extend over top of the midbrain).
There are also some features present in Archaeopteryx which are present in primitive form in the therapods but in more advanced form in the birds. In the therapods, for instance, the hallux, or big toe, is located on the back of the foot and forms a short claw that doesn't reach the ground. In birds, this toe is greatly elongated and is used for perching. In Archaeopteryx, the hallux is reversed, but is elongated to an extent midway between the therapods and the birds. In therapods, the fingers of the front arms are long; in birds, the fingers are reduced to tiny nubbins. Archaeopteryx is midway between these conditions, In birds, the wings are supported by the furcula, or wishbone, which is composed of the two fused clavicles, and Archaeopteryx also possesses a fused furcula (though not as strong as that in modern birds). A few of the therapods had clavicles, including such birdlike species as Velociraptor. And a therapod species known as Oviraptor is believed to have possessed a fused furcula, as in birds.
It is thus apparent that Archaeopteryx, although it possessed feathers and must therefore be considered to be a bird, nevertheless demonstrated many more characteristics which were unique to therapod reptiles, and must be viewed as an evolutionary transitional from therapod dinosaur to birds. And how do the creationists deal with this fossil which exhibits clear characteristics which are unique to two different "kinds"?
"The so-called intermediate is no real intermediate at all because, as paleontologists acknowledge, Archaeopteryx was a true bird--it had wings, it was completely feathered, it FLEW. . . . It was not a half-way bird, it WAS a bird." (Gish, 1978, p. 84)
"Archaeopteryx had an impressive array of features which immediately identify it as a bird, whatever else may be said about it. It had perching feet. Several of its fossils bear the imprints of feathers. These feathers were identical to those of modern birds in every respect. The primary feathers of non-flying birds are distinctly different from those of flying birds. Archaeopteryx had the feathers of flying birds, had the basic patterns and proportions of the avian wing, and an especially robust furcula (wishbone). Furthermore, there was nothing in the anatomy of Archaeopteryx that would have prevented it being a powered flyer. No doubt Archaeopteryx was a feathered creature that flew. It was a bird!" (Gish, "As a Transitional Form, Archaeopteryx Won't Fly", ICR Impact, September 1989)
Gish is here playing a word game. By arguing that Archaeopteryx is "a true bird", with nothing reptilian about it, since paleontologists classify it as a member of the bird class, Gish is ignoring the taxonomical naming requirements as they apply to the classification of transitional fossils. Birds are defined as any organism that has feathers, and Archaeopteryx undoubtedly has feathers. But classifying Archaeopteryx along with the birds does not in the least detract from its reptilian characteristics--there simply is no classification method which allows us to place Archie as a "half-reptile, half-bird". Our classification schema forces us to put it in one category or the other, and since feathers define a bird, the class Aves is where Archaeopteryx is placed.
The characteristics which Gish says establish Archaeopteryx as a bird are largely wrong. Archaeopteryx did NOT have perching feet (neither do many modern birds), and its hallux was not as well-developed as those of modern birds. The flight feathers are virtually identical to modern birds, but no downy under-feathers have ever been found on an Archaeopteryx skeleton. And, while Archaeopteryx did possess the furcula and flight feathers of modern flying birds, it did not have the large breastbone keel or the fused arm joints that are such a necessary part of flight, and it is questionable whether Archaeopteryx was capable of powered flight.
If the creationists are to argue that Archaeopteryx is really just a bird, and not a transitional between therapods and birds, they must explain all of the obviously reptilian characteristics which appear in the skeleton. Some of the reptilian characteristics found in Archaeopteryx are also found in primitive extinct birds such as Hesperornis and Icthyornis; other reptilian characteristics of the Archaeopteryx skeleton are not found in any other species of bird, living or extinct. Archaeopteryx had, for example, a full set of socketed teeth, which were typical of those found in therapod dinosaurs. While the primitive Hesperornis also possessed socketed teeth, they are no longer present in any modern bird, and according to paleontologists, these reptilian teeth were lost by the ancient birds as the avian bill began to develop. The creationists, however, are at a loss to explain why, if birds did not descend from reptiles, these primitive birds had typical reptilian teeth which later disappeared. Henry Morris, unable to give any convincing scientific explanation for this, instead invokes the Deity:
"Most birds don't have teeth, but there is no reason why a Creator could not have created some birds with teeth . . . For some reason, those that were created with teeth have since become extinct." (Morris, Scientific Creationism, 1974, p. 85)
Gish, on the other hand, attempts to explain the reptilian characteristics of Archaeopteryx by simply denying that any exist:
"Research on various anatomical features of Archaeopteryx in the last ten years or so, however, has shown, in every case, that the characteristic in question is bird-like, not reptile-like . . . When the cranium of the London specimen was removed and studied, it was shown to be birdlike, not reptilelike." (Gish, "As a Transitional Form, Archaeopteryx Won't Fly", ICR Impact, September 1989)
As we have already seen, this is simply not true--the skeletons are so reptilian in character that two of them were actually mis-identified as reptiles for several decades, and study of the cranial structure has shown it to be much more reptilian than avian.
Unable to explain how Archaeopteryx came to possess characteristics of both reptile and bird, some creationists have turned to yet another explanation--the fossils are themselves deliberate fakes, fraudulently manufactured to convince the world that evolutionary theory is true. The theory that the Archaeopteryx fossils are actually forgeries was first put forth in 1985, by two astronomers, Sir Fred Hoyle and Chandra Wickramasinghe. (Hoyle and Wickramasinghe are widely known for their extravagent and controversial claims--they are probably best-known for their theory that life began on another planet in outer space and was carried here either on comets or on extraterrestrial spaceships, as well as their theory that insects are actually more intelligent than human beings, but engage in a widespread conspiracy to prevent the humans from finding this out). They argued that the fossils had been faked by treating an ordinary Compsognathus skeleton (a small therapod dinosaur) with a paste made of limestone dust, and pressing the imprints of modern feathers into this mixture before it dried.
The British Museum conducted an extensive study on their specimen of Archaeopteryx and refuted all of Hoyle and Wickramasinghe's claims. The team found that micro-cracks in the limestone fossil extended into and beyond the feathered areas in an unbroken line, indicating that no material had been added later to the original rock. The team also found feather imprints underneath the fossil bones, which would have been impossible for a hoaxer to accomplish. Ultraviolet photography of the feathered and non-feathered areas of the fossil showed them to be identical.
Despite the fact that no evidence of a forgery has ever been found, creationists tend to take a two-pronged approach when discussing Archaeopteryx during a debate or discussion. On the one hand, they will argue, the fossil is "100% bird" and has no reptilian or dinosaurian characteristics at all. On the other hand, they will argue that the fossil is a fake anyway, made by modifying an ordinary dinosaur skeleton. The inherent contradiction between these positions--the fossil has no dinosaur characteristics, but was faked using a dinosaur skeleton--apparently doesn't concern them.
Some creationists, moreover, have seized on yet another argument against the transitional status of Archaeopteryx by arguing that true birds existed several million years before Archaeopteryx, and therefore Archie cannot be an ancestor of birds. As Gish breathlessly point out, "A fossil of an undoubted true bird has been found in rocks of the same geological period as Archaeopteryx! . . . Obviously, Archaeopteryx cannot be the ancestor of birds if true birds existed at the same time." (Gish, 1978, p. 87)
The reference here is to a fossil found in Texas by Sankar Chatterjee, consisting of a number of skull and limb fragments. Although Chatterjee has refused to allow other paleontologists to examine the fossils, he has published a description of them (particularly the skull area), and has concluded that, as well as typical reptilian characteristics (teeth, a long bony tail, and clawed fingers) they possess a number of birdlike characteristics. Chatterjee has named the bones Protoavis, or "pre-bird". The Protoavis fossils pre-date Archaeopteryx by approximately 75 million years.
Unfortunately for the creationists, the hypothesis that Protoavis was a true bird cannot yet be supported. A number of paleontologists have questioned just how birdlike the fossils really are (Chatterjee has refused to make the fossils available for the type of independent study which would settle the question one way or the other), and have concluded instead that they are a type of therapod dinosaur which possessed some birdlike characteristics (all of the therapods are very birdlike in their structure). The one structure which would definitely establish Protoavis as a proto-bird, feathers, has not been found. Even if it were definitely established that Protoavis was a bird, however, this would not help the creationist cause. Protoavis would then have to be considered as a birdlike ancestor of Archaeopteryx, and Protoavis itself would have to be considered as the earliest reptile-bird transitional.
Our picture of the evolution between dinosaurs and birds became even clearer in the late 1990’s, with the discovery of several fossils in China. In 1996, Chinese paleontologists discovered a typical small theropod skeleton with a surprise—it was covered in fine downy threadlike fibers, which accorded perfectly with incipient feathers. The dinosaur, named Sinosauropteryx ("Chinese lizard-bird"), probably used the featherlike covering as insulation.
A few years later, two more fossil species were found in the same area. Both Caudipteryx and Protarchaeopteryx were typical theropods, but were covered with recognizable feathers. Although both species had short forelimbs rather than wings, and neither was capable of flight, both had symmetrical feathers on the arms and tail, consisting of a central shaft and barbules, which probably served as an insulating cover. The body was covered with the same fibery type feathers found in Sinosauropteryx.