Originally Posted by Duane Gish
Gish, D. T. (1973) Evolution? The Fossils Say No! p57
The conversion of an invertebrate into a vertebrate, a fish into a tetrapod with feet and legs, or a non-flying animals into a flying animal are a few of examples of changes that would require a revolution in structure. Such transformations should provide readily recognizable transitional series in the fossil record if they occurred through evolutionary processes. On the other hand, if the creation model is the true model, it is at just such boundaries that the absence of transitional forms would be most evident.
The opposite is true at the amphibian-reptilian and reptilian-mammalian boundaries, particularly he former. While it is feasible to distinguish between living reptiles and amphibians on the basis of skeletal features, they are much more readily distinguishable by means of their soft parts and, in fact,, the major defining characteristic which separates reptiles from amphibians is the possession by the reptile, in contrast to the amphibian, of the amniotic egg.
p 58 (p 80 in some editions)
Many of the diagnostic features of mammals, of course, reside in their soft anatomy or physiology. These include their mode of reproduction, warm bloodedness, mode of breathing due to possession of a diaphragm, suckling of the young, and possession of hair.
The two most easily distinguishable osteological differences between reptiles and mammals, however, have never been bridged by transitional series. All mammals, living or fossil, have a single bone, the dentary, on each side of the lower jaw, and all mammals, living or fossil, have three auditory ossicles or ear bones, the malleus, incus and stapes. In some fossil reptiles the number and size of the bones of the lower jaw are reduced compared to living reptiles. Every reptile, living or fossil, however, has at least four bones in the lower jaw and only one auditory ossicle, the stapes.
There are no transitional fossil forms showing, for instance, three or two jawbones, or two ear bones. No one has explained yet, for that matter, how the transitional form would have managed to chew while his jaw was being unhinged and rearticulated, or how he would hear while dragging two of his jaw bones up into his ear.