srweaver was not asking for that kind of specifics. The question he asked was quite reasonable. If you have some fossils from before the proto-mammal or proto-insect and some, or many, after, there should be some way of determining what characteristics it should have had, what it could have looked like.
If you don't know what to expect, how would you recognize it when you find it? So we don't know what to expect, but we'll know it when we see it?