I recently read a theory that the reason nearly-modern bats seem to “pop” into the…

I recently read a theory that the reason nearly-modern bats seem to “pop” into the fossils record is because they were already evolving before the K-T extinctions. That means proto-bats were flying around in the dying age of the dinosaurs. This doesn’t relate to atheism, I just found that to be a neat (if so far unproven) theory.