Stuff like this is one of the reasosn people are quite rightly skeptical of evolution. So much of it has been junk science.
How is the sequence of reptile to mammal skulls "junk science"? It is exactly what Creationists claim has never been found-- a full series of fossils which show gradual modifications, each one only slightly different from the predecessor, but eventually leading to a whole new type of animal.
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).