Here's the short answer: because paleontology is bunk. Let's take one of the things paleontologists believe in classifying fossils: brain size. They keep saying that a larger skull shows a higher order species. This is ridiculous of course, hippos, elephants and whales have much larger skulls than humans yet none of them has built rocket ships or gone to the moon. (BTW they are following the charlatan Darwin in making this unwarranted assumption).
First off, there is no such thing as a "higher species;" species are either successful or they are not. Secondly it is not the size of the skull, but the size of the brain case in relation to the size of the body that paleontologists andzoologists use to deternime the relative intelligence of the critter in question. For instance, your average raptor (velociraptor, utahraptor, etc.) was a highly intelligent critter compared to other dinosaurs. It would've come across as a freakin' moron next to an ostrich, though.
(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.