Source: https://www.smithsonianmag.com/science-nature/oldest-known-stone-tools-unearthed-kenya-180955341/
Found on the west bank of Turkana Lake in Kenya, Lomekwi is a site where artifacts dating back 3,300,000 years ago in 2011. This pushed back the earliest known tool making about 700,000 years than previously known. At that time, this site would have been near a river and now a ravine that was discovered when 'the survey team took a wrong turn and ended up at a site now called Lomekwi 3' where they saw 'what was normally hidden by the sediment', that being 'a series of strange stones sticking out of the sediment'. There they found 149 artifacts that based on the alignment of magnetic minerals and the volcanic ash around the rocks are the oldest stone tools yet found.
Source: https://geology.rutgers.edu/images/Publications_PDFS/Harmand_et_al_2015_short.pdf
These stone tools are relatively large, with the largest weighing 15 kg and might have been used as an anvil with others that had deliberate chips knocked off them. The researchers then sought to understand how the tools would have been created and were able to recreate them in two ways: by setting the stone on a flat rock and using a hammer rock to chip away at it, or by holding the stone with both hands and hitting it against the flat base rock. Either way, the researchers said '[i]t's very rudimentary', not requiring the dexterity of later cultures but also showing clear intent and deliberate action to make them.
Source: https://www.smithsonianmag.com/smart-news/crafty-bonobo-shows-humans-arent-the-only-stone-tool-makers-32525182/?no-ist
Researchers aren't certain which hominin developed these techniques is uncertain, though it is known from observations that 'chimpanzees use rocks as hammers or anvils on their own or in the wild, and, with a little guidance, bonobos are capable of creating stone tools', pushing back against the idea that only the genus Homo is capable of tool use and making. Researchers aren't certain which hominin that was alive at the time made the tools, though Australopithecus afarensis was in the area at the time these tools were made and A africanus seems to have had a strong enough grip for tool usage, though Kenyanthropus platyops were also around this area and would have been alive at that time. The creation of these tools also indicate a 'reorganization and/or expansion of several regions of the cerebral cortex (for example, somatosensory, visual, premotor and motor cortex), cerebellum, and of the spinal tract could have occurred before 3.3 Ma [million years ago]', as well as an 'understanding of stone fracture mechanics and and grammars of action is clearly less developed than that reflected in early Oldowan assemblages and neither were they predominantly using free-hand techniques. The LOM3 [Lomekwi 3 site] assemblages could represent a technological stage between a hypothetical pounding-oriented stone tool use by an earlier hominin and the flaking-oriented knapping behaviour of later, Oldowan toolmakers'.
