Archaics and recent humans in Africa: the evidence from stone tools

An article published in Nature in February 2025 (Ben Arous, E., Blinkhorn, J.A., Elliott, S. et al. Humans in Africa’s wet tropical forests 150 thousand years ago. Nature 640, 402–407 (2025). https://doi.org/10.1038/s41586-025-08613-y) found that the belief that humans didn't enter the African jungles until recently was mistaken. The paper found "late Middle Pleistocene material culture and a wet tropical forest in southern Côte d'Ivoire, a region of present-day rainforest... demonstrat[ing] that Africa's forests were not a major ecological barrier for H. sapiens as early as around 150 ka."

I found it interesting because of the different papers (see the list at the end of this post) suggesting archaic admixture into modern humans in Western Africa, which does indicate that modern African humans did enter the jungles in that region. But, in this paper, the authors mention stone tool assemblages which in my opinion seem rather "primitive", lacking the refined appearance you'd expect from tools made by human beings 150 kya. After all, our species is said to have developed in Africa 300 kya, and left it in two waves, one, around 100 kya which is believed to have failed, and the second one that peopled the World, 60 kya. So, why would they produce tools that look so primitive? See below, an image with the upper "Unit C" tools dated to 20-12 ky and the older "Unit D" dated to 55-150 kya.

Figure S4: Stone tools from Units C and D at Bete I and III from Lioubin and Guede, and photos taken of the remaining artefact collection at the Institut des Sciences Anthropologiques de Developpement (ISAD) in 2021. Unit C: A) ‘end-scraper’, B) ‘point’, C) ‘end-scraper à museau’, D) ‘double-ended carinated end-scraper’, E) ‘small handaxe’, F) ‘fragment of a bifacial foliate piece’, G) ‘point Levallois’, H) ‘combination tool’, I) ‘end-scraper with spine’, J) ‘short foliate biface’, and K-N) ‘cores’. Unit D: O) ‘side and end chopper’, P) ‘biface - trihedral’, Q) bifacial LCT (our term), R) ‘pick with double-flat cross-section of the body and centred quadrihedral distal point’, S) ‘pick with double-flat cross section of the body and centred trihedral distal point’, T–U) bifacial pieces (our term). A-N and O, P, R and S are from Lioubin and Guede. Suppl. Mat.

The more recent upper layer exhibits, according to the authors Levallois flakes and points, while the underlying and older stone artifacts are more massive and coarse-looking: "The assemblage in Unit D, featuring large tools alongside a small tool component, may support long-held views that the diverse heavy-duty tool assemblages seen in Central and West Africa are convergent adaptive solutions to tropical forest habitation."

Sangoan toolage

In the Supplementary Material, the authors mention two types of stone industries present in Pleistocene Africa, the Sangoan and the Lupemban. Sangoan, first discovered in Sangoa, Uganda "described as late Acheulian adaptations, transitional between the Acheulean and the MSA, or as belonging to the early MSA. They are generally characterised as featuring ‘rugged’ or ‘heavy-duty’ core tools, dominated by thick bifaces, picks, choppers, and core scrapers, referred to collectively as large cutting tools (LCTs)."

The literature describes them as a transition from Early Stone Age Acheulean tool technology to Middle Stone Age tools. To me, as an amateyr un the field, this spells tools made by less advanced hominins. Acheulean tools were the mark of H. erectus, and these crude Sangoan tools are common in Central Africa during the Upper Pleistocene, and coexist with Modern Humans in West Africa 150 kya? Strange overlapping of superarchaic hominins with modern H. sapiens.

The coarse and heavy build of Sangoan tools is believed to be due to their use in forested environment, for chopping or digging for edible roots and tubers. They have been found at Kalambo Falls in Zambia and dated to 500-300 kya. Clearly not the work of Homo sapiens, we appeared only 300 kya. In Simbi, Kenya their age is between 50-200 kya, indicating a survival of an ancient technology overlapping the appearance of modern humans and possibly, the survival of the archaics that made the Sangoan stone tools.

Lupemban

The Lupemban, on the other hand, named for a brook in Zaire, is different it displays careful crafting using Levallois core and flake technology, resulting in refined lanceolate, bifacial points. The oldest Lupemban tools are 266-132 kya. Overlapping with the more primitive Sangoan, as if two different groups of less, and more advanced hominins created them to exploit the forests and jungles (see this source for a comprehensive text on this industry).

Closing Comments

Rather than showing that modern humans were living in the West African jungles 150,000 years ago, the paper by J.A., Elliott, S. et al. seems to suggest an overlapping of different people in that area, namely archaics with early stone age Lupemban tools and modern humans with Sangoan ones.

Why would archaeologists ignore the signal provided by the Acheulean-like Sangoan tools and attribute them to modern humans living in a forested environment? In Eurasia, stone technologies, like the Mousterian are a clear indication of Neanderthal craft, why wouldn't the Sangoan be taken as a lithic technology developed by non-sapiens people? It seems to me that archaeologists focused on Africa have the obligation to defend the antiquity of Homo sapiens in that continent and ignore facts that indicate the opposite.

Below are some posts on the admixture of archaics and moderns within Africa: ↺

• May 2018: Archaic hominins admixed with Pygmies in Africa, citing: Psing Hsun Shieh et al, 2016. Summary: at least one introgression of archaics into pygmies ~9 kya.
• May 2018: More on archaic introgression into H. sapiens in Africa: the source of African's genetic diversity, citing: Hammer et al., 2011. Summary: modern Africans' DNA has a ~2% introgression that took place ~35 kya, from an archaic that split from our lineage 700 kya.ed DNA, ) that introgressed ~35 kya from an archaic population that split from the ancestors of anatomically modern humans ~700 kya
• May 2019: Archaic Ghost population admixed with Modern Humans in Africa, citing: Lorente-Galdos et al, 2019. Summary: a divergent ghost archaic population that split from the ancestors of modern humans 528 kya introgressed into Africans at the following frequencies:~ 4.0% in Khoisan, ~ 4.3% in Mbuti Pygmies, and ~ 5.8% in Mandenka.
• June 2019: Archaic humans admixed with modern humans in Africa, citing: S. Langley, Miga, Karpen, C. Langley, 2018. Summary:a distinct, old introgressed archaic lineage (~1.1 MYA) consistent with recent admixture with an extinct archaic in Africa.
• February 2026: On the Diversity of Africans, citing: Durvasula and Sankararaman, 2020. Summary: introgression into four West African populations, with frequencies of 2 to 19% from an archaic population that diverged before the split of Neanderthals and modern humans. It took plase 43 kya (95% HPD: 6 - 124 kya).
• February 2026: Diversity in Africa. Some explanations on why it is so diverse, citing: Skoglund et al., 2017, Jakobsson et al., 2025 and Padilla-Iglesias et al., 2025. Summary: deep stratification in Africa may come from admixture with an unknown archaic African group predating the divergence of Humans from Neandertals and Denisovans. Western Africans may have introgressed with archaics.
• April 2026: A New March 2026: Paper on Archaic introgressions in Humans, citing: Zhang, Biddanda, Johnson, O’Dushlaine, Moorja, (2026). Summary: two introgressions with super-archaics. (i) inside of Africa with a ghost population that diverged from ours over 500 kya it is found in all humans, Africans and non-Africans.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

The Pampas, the ideal spot to look for Denisovans or Homo erectus

Following my post on the possibility of Denisovans expanding their territory and moving east, into America, one of the followers of my blog, Marcelo Bruyere wrote a comment to the post, suggesting that old sites such as those that would correspond to a Pleistocene peopling of America before the last glacial period would have to be located beyond the area scoured by the glaciers of ice ages that followed their migration 400,000 years (400 ky) ago. Sites located in temperate regions would be safe from the destructive effects of the glacial ice fields.

Marcelo mentioned the Cerutti Mastodon site which is 130 ky old which is in California, 32°S as an example and suggested that South America would also be a great place to search for such sites, but not in caves or rock shelters, which are the favorite haunt of archaeologists looking for ancient campsites. Instead, he says, these sites should be sought "in other environments; such as possible relicts of ancient plains bearing rivers and/or lacustrine systems, that could comply with the condition of having been originally developed in terrains well deep into the Pleistocene" and continues, proposing the Argentine plains known as the Pampean region as a suitable place to look for this type of sites.

The Pampa Region

The Pampas, whose name comes from the Native American Quechua language and means "plain", is a vast expansion of flat prairies originally covered with native temperate grasslands, with a very slight west to east incline, spanning 1.2 million km² (460,000 sq. mi.). The region is outlined with a red line in the map below:

Its western flank rises to about 200 meters (600 ft.) into an arid area with an open savanna-like region of "monte" and "espinal", with caldén trees, that then becomes even more drier as it blends into the Cuyo Andean Region, and the Northern Patagonia. The eastern part is more humid and is lower. Two ancient mountain ranges from the Precambrian and Paleozoic jut out of the lowlands in south-central Buenos Aires province, the Sierra de la Ventana which reach their maximum altitude with the Cerro Tres Picos (1,240 m - 4.066 ft) and the Tandil hills with 500 m (1,600 ft), these continue beneath the overlying silt, and form the basement on which the plains were formed during the Cenozoic period. Sediments originating in the Andes mountain range, were eroded and transported east by the wind (aeolian) and rivers (fluvial) and deposited on the granite bedrock over the past 12 million years (Zárate & Folguera, 2009).

Of the different cycles of sedimentation, the one we are interested in is the third one, which took place during the "...late Pliocene-late Pleistocene circa 3.2 Ma- 0.040/0.030 Ma [it] includes deposits bearing Marplatan, Ensenadan and Bonaerian fossil remains. They are distributed in the Salado tectonic basin, forming the bedrock in which fluvial valleys are excavated." Zárate & Folguera, 2009. Marcelo points out that the "undulating" Pampa, which is an area located in the northeastern corner of Buenos Aires province, with low-lying hillocks (a "gently rolling landscape" (Zárate, 2002) that break the flat plains " is a particularly good example of a suitable one for this purpose because; a) it overlies a massive (30 meters thick) Pleistocene substrate whose geological record goes all the way down (although with hiatus) from 12/13 Ka to the vicinities of Matuyama/Gauss boundary (ca. 2,58 Ma), b) it is crossed by many rivers whose valleys are deeply incised into this substrate, and c) also presents some relict landscapes outcropping subaerially (albeit, conditionally accessible), whose geological levels are within Matuyama magnetic ages (>0.78 Ma)."

This region has produced many megafaunal fossils and also human remains corresponding to Paleoindians. To clarify the text, the Matuyama boundary is a period that lasted from 2.59 to 0.78 Ma and marked a reversal of the Earth's magnetic field. During this time, a compass wouldn't have pointed north, it would have pointed south. Point c) mentions that some of the deeper layers are accessible in this region, on the surface, exposed ("Subaerial").

It was in the banks of the rivers that cut across the plains, that the first megafaunal fossils were recovered during the late 18th century and sent back to Spain from the Colonial Buenos Aires: the Megatherium americanum described by Cuvier in 1796. These were considered antediluvian creatures. The banks of these rivers still provide fossils (Scanferla, 2013, Chichkoyan, 2022).

The mid Pleistocene sediments are not that deep. For instance Tófalo, 2011 reports "Present day soil is found at the top of the section. Its parental material was sampled at 1.2 m [4 ft] where an OSL dating yielded an age of 30 ± 4 kyr. Another OSL age >126 ± 10 kyr for a sample taken at 7.3 m [24 ft]" Sediments that could potentially contain Denisovan or erectus remains would be at that depth.

Interestingly, current research has looked into these locations and found old pre-Clovis tools dated to 30 to 40 ky ago. See Marcelo Toledo, 2017, whom I quote below. Toledo reported finding a flint tool that "was unambiguous as well as embedded into basal sand of the Red Luján sequence (a geological sedimentary layer), which have been dated between 25 and 30 ky BP... These preliminary results prove human presence towards 25-30 ky BP in the Luján valley." These tools are obviously man-made because there are no sources of stone or rocks nearby (these plains span hundreds of kilometers, and the nearest rock sources are over 200 km away (125 mi) and couldn't have reached this area in any other way other than by human transportation.

One hundred and forty years ago, Florentino Ameghino, who proposed an autochthonous origin, in America, for humans, who then migrated across the globe (one of these ancient human specimens was the Diprothomo platensis) supported his theory with fossils and early, cobble-styled tools that he had found similar tools along the Lujan River banks, and also bones of megafaunal animals that bore clear stone cut marks.

Ameghino called these primitive tools "eolithic" (Greek for "dawn stones"), refraining from using the term "paleolithic" because they differed substantially from the Acheulean industry found in Paleolithic Europe. These stones were old, and different as you can see in the following image:

Some eolithic tools described by Amgehino in 1881, Frias II site . Source

And these sites are just scraping the surface, the most recent sedimentary layers, below are more, reaching down to almost 1 million years.

The idea that hominin remains from 50,000 to 800,000 years ago may be buried by tens of meters of silt in these open plains is exciting, and as we have seen, some proof has already been discovered.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall ©