The fossil record clearly shows that new species occupy specific time periods and appear to have been well adapted for their environment. There is abundant evidence that they were preceded by species with the same trait but less developed, and succeeded by species with the same trait but either more developed or atrophied due to irrelevance.
Only a tiny fraction of individuals in a species actually encountered circumstances that permitted fossilization. In general the fossil record captures mostly the species that flourish greatly. The less flourishing species never make it into the record.
In most cases the flourishing species are evolutionary dead-ends. Although they shared features of later species, the later species did not directly descend from the earlier.
We can be confident that there was a species that was a common ancestor to different species showing a progress of a certain trait. However, the fossil record is mostly silent about recording that common ancestor species.
The common ancestor species was the one that introduced the innovation that the later species enjoyed. Natural selection says that this trait would have offered a survival advantage that eventually displace the less adapted population. This may be true, but the lack of fossil evidence of the exact common ancestor species indicates that the adaption most often does not result in the species flourishing to as great of numbers as its dead-end descendants.
Viewing evolution as a tree with a trunk representing common ancestors and branches indicating of dead-end descendant species may be misleading. Unlike a tree that has a thick voluminous trunk and thin branches, the evolution tree has an invisibly small trunk with very thick branches or even thicker twigs.
The survival advantage of an innovation is mostly enjoyed by distant descendants and not the species that introduced the innovation.
The distant descendants that most enjoyed the survival adaptation did not leave any descendants. It is as its flourishing discourages further evolution.
Evolution may be survival of the fittest but it seems to progress along the weakest branches.
Evolution is stealthy.