Systematic bone tool production at 1.5 million years ago

Tyler Cowen just posted this abstract at Marginal Revolution:

de la Torre, I., Doyon, L., Benito-Calvo, A. et al. Systematic bone tool production at 1.5 million years ago. Nature (2025). https://doi.org/10.1038/s41586-025-08652-5

Abstract: Recent evidence indicates that the emergence of stone tool technology occurred before the appearance of the genus Homo and may potentially be traced back deep into the primate evolutionary line. Conversely, osseous technologies are apparently exclusive of later hominins from approximately 2 million years ago (Ma), whereas the earliest systematic production of bone tools is currently restricted to European Acheulean sites 400–250 thousand years ago. Here we document an assemblage of bone tools shaped by knapping found within a single stratigraphic horizon at Olduvai Gorge dated to 1.5 Ma. Large mammal limb bone fragments, mostly from hippopotamus and elephant, were shaped to produce various tools, including massive elongated implements. Before our discovery, bone artefact production in pre-Middle Stone Age African contexts was widely considered as episodic, expedient and unrepresentative of early Homo toolkits. However, our results demonstrate that at the transition between the Oldowan and the early Acheulean, East African hominins developed an original cultural innovation that entailed a transfer and adaptation of knapping skills from stone to bone. By producing technologically and morphologically standardized bone tools, early Acheulean toolmakers unravelled technological repertoires that were previously thought to have appeared routinely more than 1 million years later.

Here's a comment I posted:

Some years ago I visited Ralph Holloway's lab at Columbia. Holloway is a physical anthropologist and an expert on the evolution of the brain. The lab was, say, 15 by 20 feet, maybe a bit larger but not much larger. It had tables and shelves where you could see the specimens, skull fragments of various sizes. There may have been one or three fairly complete skulls, but not many. Anyhow, this is the kind of evidence we have for brain evolution, fragmentary and indirect.

Holloway said that that lab had, say, 10% of the world's total collection of hominin skull fragments. This was back in the early 2000s. When you do a thumbnail estimate of the population these specimens were drawn from, it becomes clear that the total world-wide collection of specimens is a very small fraction of that population. And we have no reason to think that the that fraction is random. It may be, it may not. We don't know.

When that's the kind of evidence you're working from, one new discovery can wreak havoc with existing theories.