Technically 'prehistoric' could fit. The remains are from a time before written records existed there. But when you consider that written records had already l

Technically 'prehistoric' could fit. The remains are from a time before written records existed there. But when you consider that written records had already long existed elsewhere in the world and that 'prehistoric' can go as far back as ancient mammals and even dinosaurs, it becomes a rather vague term. However, in this case it's useful to describe it as prehistoric because this is the only type of evidence we have of their culture. Since there are very few written records, archaeological remains are the best bet for learning more about them, which is why finding something this well-preserved can be particularly exciting. Otherwise, as far as I know human the brain belonged to is pretty much anatomically and genetically the same as modern humans.