But there is little odd part to this story. Only 90-percent of animals fell into this category. The other 10-percent did NOT come from that era. So the question ought to be which animals fell into the ‘modern’ era and which extend beyond that era.
I would suggest that this whole DNA discussion is not finished, and there’s going to be a number of issues laid out which won’t fit well with any narrative.
Maybe the other 10% are the results of crossbreeding
In a few thousand years people on Mars will discover 90% of animals came ‘into existence’ around the same time ... AND that ‘all the links’ between their creatures are missing...