This new model implies a relatively skeptical view of the completeness of the fossil evidence as a record of the evolution of segmented organisms. It is antithetical to the view that the fossils and the existing animals so far discovered can be arranged to provide a satisfactory illustration of the process of evolution.
Anyone would agree that although we have storerooms of unevaluated fossils, the number of species known is small relative to the number of animals that have existed. The question is, how representative of evolutionary history are these fossils? Do these fossils show us what we want to know? Paleontologists have tended to argue in favor of the significance of their stock in trade.
In a sense, every crumb of evidence is precious. But will more fossils of dinosaurs or auks or trilobites or odd-looking fishes bring us closer to understanding the origin of these complex organisms? Probably not. The facts imply that there was a formative stage of which we seem to have no direct evidence; this blank area can only be filled in with theory.
The new model is based not on recapitulation theory and the paradigm of increasing complexity, but on the pattern of evolutionary reduction shown by the fossils and on theoretical considerations regarding the difficulty of forming new symmetrical parts or segments though gradual evolution.
The fossils suggest that a successful new form--accessing a new niche--will quickly develop specialized morphology. This would logically be the case for the proposed protovertebrate, since it was a mass of unspecialized segments in a world of unexploited or undeveloped niches. Its existence in the idealized form depicted must have been brief and localized; presumably at least slightly specialized forms would accomplish the first radiations. I do not expect fossils of the proposed protovertebrate to be found.
Regarding the conventional model for gradual elaborative evolution of the vertebrate limb, a correspondent once advised me that "There is no guessing how it happened, we have it preserved in the stone." But generations of brilliant catastrophists and creationists have passed away, confident that their beliefs were similarly confirmed. When we are working in the dark, we rely on general principles.The proposed model follows from the pattern of reduction shown by the fossil evidence, while the current model arose from the unquestoned notions that evolution proceeds from the simple to the complex, and that embryonic development mirrors evolutionary history.
Given that some believe that the existing animals may be placed in a simple-to-complex order which illustrates evolution, it is not surprising that a similar arrangement including fossil animals should be convincing to many. But in either case, a history is being synthesized to conform to a certain evolutionary model. There has long been a tendency to accept the Linnean classificatory structure as the evolutionary ladder.
Paleozoic organisms appeared suddenly, and they were as complex in every sense as modern organisms. The terrestrial vertebrate limb seemingly did not exist in the early Paleozoic Era, but lungfishes with many limb bones did. A fossil sequence may be presented showing evolution of the variety of tetrapod limbs through reduction of the lungfish limb which is just as plausible as the familiar elaborative sequences, in which reptiles with few digital bones--such as rhipidistians--are presumed to be ancestral to later animals with more digital bones, such as primates.
Darwin referred to the "imperfection" of the fossil record; contemporary evolutionists admit to "gaps" in the fossil record. This language is disingenuous, reflecting an intention to smooth over difficulties in the cause of promoting the theory of evolution. What is the fossil record a record of? If it is a record of the smooth transition of animals toward greater complexity, it is indeed imperfect. But if there were formative stages which were geologically instanteous, then the fossil record is as good as could be expected.