Conversely, at each known stage of human civilization, how long will it be before evidence of that civilization becomes unknowable through future archaeology?
Because animal and plant species were very separated, until the "invasive species" phenomenon the last few centuries.
Odds are if there had been an advanced ancient civilization of any size (and an advanced one is going to tend to be large) and for any length of time, they'd have done quite a bit of lead smelting (lead's really useful and super-easy to smelt... shame it's poisonous), and we'd see it in the ice core record.
Let alone something like fossil fuel use. Plus probably dozens of other markers of iron-age industry or later, that I don't know about.
I very much doubt any very-ancient humans/hominids got past Bronze Age tech, at best. If I had to place a bet on it, I'd bet against them having gotten past stone-age tech at all. I think we'd see evidence of it.
Charcoal and iron mining is simply highly visible.
What is "advanced"? Is it a property everyone would agree on? Is it a single scale or some multi-dimensional ordering?
If a civilisation has beautiful spoken-word poetry, while the other has a tradition to play a complex game with baskets and grass knots which one is more advanced?
They seem like the natural frontrunner, in my eyes.