We humans must have originated in some kind of a cement mixer, to judge from recent reports.
Making stone tools (Oldowan technology) is believed to have started in East Africa 2.6 million years ago and spread from there. But archaeologists recently found stone tools and butchered animals on a high plateau in Algeria:
The newly discovered limestone and flint tools are about 2.4 million years old — almost the same age as the oldest known such tools, which were found in Gona, Ethiopia, and are 2.6 million years old.
The discovery means that hominins were present in the Mediterranean fringe of North Africa around 600,000 years earlier than previously thought. Aisling Irwin, “Algeria fossils cast doubt on East Africa as sole origin of stone tools” at Nature
Abstract: East Africa has provided the earliest known evidence for Oldowan stone artifacts and hominin induced stone tool cutmarks dated to ~2.6 million years ago (Ma). The ~1.8 Ma stone artifacts from Ain Hanech (Algeria) were considered to represent the oldest archaeological materials in North Africa. Here we report older stone artifacts and cutmarked bones excavated from two nearby deposits at Ain Boucherit estimated to ~ 1.9 Ma, and the older to ~2.4 Ma. Hence, the Ain Boucherit evidence shows that ancestral hominins inhabited the Mediterranean fringe in Northern Africa much earlier than previously thought. The evidence strongly argues for early dispersal of stone tool manufacture and use from East Africa, or a possible multiple origin scenario of stone technology in both East and North Africa. (open access) – Mohamed Sahnouni1,2,3,*, Josep M. Parés1, Mathieu Duval4,1, Isabel Cáceres5,6, Zoheir Harichane2,7, Jan van der Made8, Alfredo Pérez-González1, Salah Abdessadok9,2, Nadia Kandi10, Abdelkader Derradji2,11, Mohamed Medig11, Kamel Boulaghraif2,12, Sileshi Semaw1,3 1.9-million- and 2.4-million-year-old artifacts and stone tool–cutmarked bones from Ain Boucherit, Algeria, Science 29 Nov 2018: eaau0008
DOI: 10.1126/science.aau0008 More.
From others: It’s not clear what human group created the tools. No human bones were found at the site:
The animal bones also provided clues. Many of them came from species of extinct pigs, horses, and elephants that only lived within certain time frames, which the team checked against the dates from their magnetic calendar. This work, which took most of the decade to do, revealed that the two areas the team dug up were 1.92 million years old and 2.44 million years old. Ed Yong, “2.4-Million-Year-Old Stone Tools Turn Up in an Unexpected Place” at The Atlantic
The bones came from the ancestors of crocodiles and hippopotamuses too:
One hypothesis is that early ancestors of modern day humans quickly carried stone tools with them out of East Africa and into other regions of the continent.
Another is a “multiple origin scenario,” in which early hominids made and used tools in both East and North Africa. “2.4-million-year-old tools found in Algeria could upend human origin story” at Agence France Presse
See also: Complex stone tools from 160,000 to 170,000 years ago found in China
Stone tools found in Saudi Arabia from 300,000 years ago
How did stone tools get to the Philippines 700 kya?
Revolutionary stone tools found in India “much earlier than thought,” 385 kya
Stone tools confirmed from 3.4 mya?
Stone tools now dated to 3.3 million years ago