Archaeopteryx part 2
Let’s say we decide that the bone structure of the Archaeopteryx is definitely reptilian, from which line of reptiles is it related? Surely, there would be traces of one or the other.
Martin, Stewart, and Whetstone, “The Auk” (Ornithological Journal) January 1980 page 86 “The Origin of Birds: Structure of the Tarsus and Teeth”
“…virtually every major group of reptiles has been purported to be closely related, if not ancestral to birds.”
In the report they briefly mention two hypotheses concerning Archaeopteryx and proceed to push their own- crocodile ancestry based on teeth. The hypotheses are:
1) A theory of their ancestry from Triassic pseudosuchian archosaurs.
2) A theory of direct derivation of birds from theropod dinosaurs.
3) A close relationship between birds and crocodilians.
It should be noted that in their report that altho’ they concentrated on the Archaeopteryx, the authors clearly related the teeth of this bird to the teeth of later Mesozoic birds and spoke of them as one in the same. They were mainly dealing with the origin of teeth in all teeth-bearing birds.
In another report that I mentioned a while back in “Nature” Sept 8 1983 pp99-100 entitled “No consensus on Archaeopteryx” The author Dr. Michael Benton (not to be confused with Dr. Michael Denton) concerning the different theories:
” The relationships of Archaeopteryx and the origin of the birds are controversial. In a recent review, Thulborn and Hamley identified seven hypothses concerning the affinities of Archaeopteryx, three of which appear to have supporters at present.”
Just prior to this, Dr. Benton discusses the results of Archaeopteryx cranial studies:
“In the new work that has been done on the braincase of Archaeopteryx by Whetstone, the cranium of the ‘London’ specimen has been removed from its limestone slab and painstakingly prepared by mechanical means.
This has shown that the skull is much broader and more bird-like than had been thought. Details of
the braincase and associated bones at the back of the skull seem to suggest that Archaeopteryx is not the ancestral bird, but an off-shoot from the early avian stem.” He goes on for the rest of the paragraph discussing very briefly how it is primitive in some respects and advanced in others. But basically the Archaeopteryx has been, according to him, relagated from the lofty position of being the transition between reptile and modern bird to that of just another “side branch” of evolution.
So you see, the reptilian features of the Archaeopteryx are so obscure and ambiguous that trying to pin down its ancestral relationship is just about impossible. Forcing the Archaeopteryx into the role of transition has proved to be nothing but a fruitless exercise.
But let’s say for the sake of arguement that the Archaeopteryx’s bony structure can be related to reptiles as well as birds. Does this still necessarily force us to conclude that it is transitional?
“Evolution: Nature and Scripture in Conflict?” by Dr. P.T. Pun copyright 1982
Archaeopteryx has been cited frequently as the transitional type between reptiles and birds. It has a birdlike skull and wings with feathers. The reptile features are presented by clawlike appendages, the possession of teeth, and the long vertebral column that extends to the tail. The flying power of this organism was presumably slight, for the wingspread is much less than that of the poor flyers among modern birds.
Since most skeletal features of birds can be matched by some archosaurian reptiles, feathers have been considered the only distinctive feature of birds. Feathers are essential to birds for insulation against loss of body heat, and this contrasts greatly with reptiles since they are cold-blooded. Therefore, Archaeopteryx was definitely bird.
However the presumed small sternum, the primitive reptilian structure of wing bones, and especially the long tail set Archaeopteryx apart from most modern birds, requiring a separate subclass to represent it. However, some reptilian structures of this fossil are shared by some modern-day birds. For example, the juvenile stages of Opisthocomus hoatzin of South America and Touraco cory thaix of Africa possess claws, and both are flyers…
…More specifically, L. de Nouy, an evolutionist, commenting on the status of Archaeopteryx has made a very succinct statement concerning the establishment of “true links” between major groups. While recognizing the morphological similarities of Archaeopteryx to reptiles and birds, he nevertheless concluded:
“By link, we mean a necessary stage of transition between classes such as Reptiles and Birds, or between
smaller groups. An animal displaying characters belonging to two different groups can not be treated as a true link as long as the intermediary stages have not been found, and as long as the mechanism of transition remains unknown.”