That was the whole point of punctuated equilibria."
Every fossil, without exception, is an "intermediate fossil" -- intermediate between its ancestors and its descendants.
And since minor DNA mutations are observed in every generation, no individual is genetically precisely the same as its ancestors or descendants -- it's "intermediate."
So lined up side by side, we can see in fossils of dozens of pre-human breeds, sub-species, species and genera, the "intermediate" nature of each one -- as they evolved from more chimpanzee-like ancestors ("A" below) to more human-like forms ("N" below).
"Punctuated equilibria" are explained by the fact that once a species has evolved to perfectly fit its environment, then every significant mutation will be for the worse, and so get weeded out by natural selection.
Only when the environment itself changes (becoming warmer, cooler, wetter, dryer or a new predator, etc.), can some mutations improve an individual's chance to survive and reproduce, and then a species can begin to evolve again.
