Archaeologists recently announced the discovery of the oldest stone tools ever. These tools represent a key moment in our ancestors technological development. They mark the moment our ancestors began creating new tools, rather than simply using whatever was in the environment. This important toolkit - called the "Lomekwian" - is 3.3 million years old; more than a million years older than anything vaguely human. Which raises the question: if humans didn't make them, who did?
Meet the contestants
At the same time as scientists announced the discovery of the oldest stone tools another team discovered a new member of the human family. Called Australopithecus deyiremeda; they join several other species living at the same time the Lomekwian was made. These were:
- Australopithecus afarensis. The famous Lucy fossil belongs to this species. She's one of the most complete human fossils ever found, so we know an awful lot about them. Including the fact that they lived in the right time and place to be the manufacturer of the Lomekwian. In fact, their name "afarensis" comes from the Afar region of Africa - the same region these tools were found.
- Keyanthropus platyops. This species could be significant, it's hard to say. On the one hand it does have a relatively flat face and small molars. These are features similar to later humans, suggesting it could be their ancestor. On the other hand, most of our information about this species comes from a mangled skull. Hard to say anything with much certainty when that's all you have to go on.
- Australopithecus deyiremeda. Newly discovered and already making waves. The existence of Australopithecys deyiremeda was announced just last week. It lived in the right time and place to be the creator of the oldest stone tools.
- Australopithecus bahrelghazali. Little is known about this mysterious species. All we've found is a lower jaw, nicknamed "Abel". What we do know is that it lived at around the same time as the Lomekwian was being made. However, it lived in hundreds of miles away from these tools. So it's an unlikely candidate.
So who made the oldest stone tools?
So we have a bunch of possible creators. Who actually made the oldest stone tools? Well, the discoverers of the Lomekwian reckon they have an answer: the mysterious Kenyanthropus platyops. In their paper announcing the discovery of the Lomekwian, they note it comes from the same sediment Kenyanthropus fossils have been found in.
Which is rather frustrating, given that's the candidate we perhaps know least about. With just a mangled skull to go on, the very existence of Kenyanthropus platyops is debated. Some argue it is simply a smashed up example of Australopithecus afarensis or some other species. And this finding won't resolve that either. There can be technological differences between chimpanzee groups, so there could be differences between groups of our ancestors. The fact they made a special tool doesn't prove they were a unique species.
However, if it is proved this is a real species then this could have some very interesting implications. They share some similarities with later species - including us - raising the possibility that they might be their ancestor. If it turns out they also made stone tools - something else those later species did - then that would be another point in favour of that relationship.
Kenyanthropus might have just flint-knapped their signature onto the story of human evolution.
References
Boyd and Silk, 2012. How Humans Evolved
Harmand, S., Lewis, J. E., Feibel, C. S., Lepre, C. J., Prat, S., Lenoble, A., ... & Roche, H. (2015). 3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya. Nature, 521(7552), 310-315.
