(a)That is totally unresponsive to the point I was making in the post you were replying to, which is that the sequence of reptile-to-mammal fossils shows what creationists say doesn't exist (a long series of small, gradual changes all eventually leading up to the development of an entirely new type of living thing).
(b)I, and, AFAIK, no reputable paleontologist, have never claimed that a larger skull per se shows "a higher order species." In tracing the ancestry of hominids, we do see gradually larger skulls from australopithecus to homo erectus to homo sapiens. No one has ever claimed that hippos are a "higher level species" than humans. And none of this discredits the reptile-to-mammal fossil sequence.
Be careful of your use of words.
From others posts relating to the use of lizard.
The relationships of these fossils indicate that amniotes first diverged into two lines, one line (Synapsida) that culminated in living mammals, and another line (Sauropsida) that embraces all the living reptiles (including birds).
No it is not. The problems of paleontology, and specifically the problem I have been discussing - the lack of evidence it truly provides for most of the significant changes in organisms relates directly to this. In fact, only the circular assumptions of paleontology tell us that no animal without three ear-bones could have been a mammal. We have fish nowadays that are mammals, paleontology cannot tell us whether some of the fish we know only by bones nowadays were mammals or not, it can only tell us that they did not have 3 earbones. Changes in bone structure tell us very little. The bones represent a very small part of the genome of an organism and the most interesting parts, the ones that tell us the most about an organism and which need to have evolved also and paleontology can give us no proof of them are the development of what most of us would call the "entrails" of the organisms. Look up the platypus and tell me how many of the unique features of it would have been determined just from the bones.