Not six mya but only 4 mya, different experts claim.
In “Scientists are accused of distorting theory of human evolution by misdating bones” (The Guardian Observer, 10 June 2012), Robin McKie reports,
La Sima de los Huesos – the Pit of Bones – has been designated a Unesco world heritage site because of its importance to understanding evolution, and millions of euros, donated by the EU, have been spent constructing a museum of human antiquity in nearby Burgos.
But Britain’s leading expert on human evolution, Professor Chris Stringer, of the Natural History Museum, has warned in the journal Evolutionary Anthropology that the team in charge of La Sima has got the ages of its fossils wrong by 200,000 years and has incorrectly identified the species of ancient humans found there.
Far from being a 600,000-year-old lair of a species called Homo heidelbergensis, he believes the pit is filled with Neanderthal remains that are no more than 400,000 years old. The difference in interpretation has crucial implications for understanding human evolution.
The most “crucial implication” is, don’t take any of it too seriously.