Early Stone Age hafted spear points from South Africa

This week in Science, Jayne Wilkins and colleagues report on part of the lithic assemblage from Kathu Pan, South Africa, which includes 210 points Wilkins:hafted:2012. The paper reports that these are the earliest known hafted points in the world, predating the previous record by more than 200,000 years.

The minireview of the spear literature:

By ~780 ka, hominins were regularly killing large game, based on evidence of repeated in situ processing of complete carcasses of fallow deer at Gesher Benot Yakov in Israel (4). At the English site of Boxgrove, a horse scapula with a semicircular perforation is consistent with spear-aided hunting by ~500 ka (5). Wooden spears dating to ~400 ka have been found in association with butchered horses at Schningen, Germany (6). Hafted spear tips appear to be common in the MSA and Middle Paleolithic (MP) sites of Europe and Africa after ~300 ka (720).

This is a very short paper, and it sets out two problems: demonstrating that the points really are 500,000 years old, and demonstrating that they really were used as spear tips. The first is fairly straightforward as a function of the stratigraphy at the site and some ESR/U-series dating of faunal teeth. Possibly a broader issue is the identification of the assemblage as Fauresmith, which has been poorly defined in the literature and sometimes means different things. It is more or less indicative of assemblages based on large cutting tools (such as handaxes), with an increased fraction of flake core production and some MSA-like elements. Andy Herries published a good review of the Fauresmith issue and its chronology last year Herries:Fauresmith:2011. He wrote this with respect to Kathu Pan:

Previous dating of the site was based on elephant fossils that were more evolved than those from Olduvai Bed IV [62]. This simply gave the site an age of <1.07?Ma or <780?ka based on the interpretation of the palaeomagnetic data [6]. At Kathu Pan, the MSA layers fall in the time range between 336 and 254?ka (291 45?ka; [148], perhaps during MIS9 (340310?ka). The layer 4a Fauresmith assemblage at Kathu Pan contains Levallois cores, retouched points, blades and LCBTs and has been dated, to somewhere between 511 and 435?ka based on a combination of OSL (464 47?ka) and ESR (542 + 107/?140?ka) [148]. Porat et al. [148] suggest that the OSL age may represent a minimum age estimate. If so, the layer would date to between 682 and 435?ka (based on ESR alone). An MIS13 age (540470?ka) might be a good estimate based on this data but certainly older than 417?ka. This suggests that all the tool forms found in the MSA are already in place by at least 417?ka. The retouched points have facetted platforms and are in stark contrast to early MSA assemblages that are suggested to lack formal tools and retouched points [148]. Porat et al. [148] note that the extreme lateral convexity of the lithics distinguishes them from the norm for the Levallois method, despite the fact that they typologically and technologically fit within the Levallois. The age of the Acheulian 4b layers has not been determined other than being older than 4a. Porat et al. [148] note that LCTs in the Fauremsith horizons are made on a wide range of raw materials and are crude and irregular, while those from the Acheulian are exclusively made on banded ironstone and are symmetrical and refined. This may reflect the hominins developing new raw materials for LBCT manufacture during the Fauresmith as part of experimentation of new methods of stone tool manufacture. The occurrence of a Fauresmith industry at Kathu Pan, so close to Wonderwerk Cave, dated to >417?ka may lend weight to the Fauresmith at Wonderwerk also being in this time range or at least older than 182?ka as suggested by Chazan and Horwitz [147] unless it occurred for over 200?ka in the region and was being produced contemporarily with the MSA.

Fauresmith at some other sites in southern Africa, including Wonderwerk Cave, is apparently younger, less than 300,000 years ago. The entire range is coincident in time with the Early-Middle Stone Age transition in the Kapthurin Formation sites in Kenya, which makes these "transitional" assemblages really representative of a long-term pattern of variability and change. The marker of MSA industries as opposed to Early Stone Age is the MSA's reliance upon prepared core reduction techniques. Yet, prepared core techniques (like the Levallois technique) appear much, much earlier. One marker of the MSA, as reviewed by Herries Herries:Fauresmith:2011 (citing McBrearty and others) is the appearance of projectile point technology:

Mcbrearty [22] also suggests that the fundamental change from the ESA to the MSA is the end of LCTs and a shift to projectile point technology. Of course, it should be noted that Acheulian bearing hominins in Europe were utilising an entirely wooden projectile technology for hunting as shown by the occurrence of the Schningen spears at either ~400 (MIS 11 [157]) or ~310?ka (MIS 9d-e; [168]) but were seemingly still disarticulating their kill with LCTs. Whether a similar wooden projectile technology was being used by hominins in Africa is almost impossible to tell given the almost complete lack of preservation of such organic remains in most MSA sites. The exceptions are two wooden tools from Floor 1 at Kalambo Falls in Zambia [30, 56] and one from Florisbad in South Africa [13]. Other sites where large pieces of wood have been recovered include the Acheulian sites of Amanzi Springs [73] and Gesher Benot Ya'aqov [169]. Despite the discovery of significant amounts of wood from these deposits, no tools have been noted. The Kalambo falls tools are reminiscent in some ways of the European spears and are associated with large well-formed cleavers from the Acheulian bearing Floor 2, below the Sangoan. Given their context these wood tools might be older than those from Europe and might point to a wooden projectile point technology in the late Acheulian, complimenting the earlier LCT technology. At most sites, the only clue would be in finding injury patterns on faunal remains indicative of such activities. In a similar vein, the co-occurrence of LCTs and projectile point technology in the Sangoan and Fauresmith may reflect similar activity patterns, or as McBrearty [22] suggests that the mix of technologies may, in fact, represent different hominins using different technologies at the same time in the same regions of Africa.

This brings us to the current paper, which pushes the appearance of projectile points back well before the clear appearance of the MSA. So is the evidence solid?

Triangular stone flakes may look on the surface like spear points, but that doesn't necessarily mean they were used that way. Triangular flakes are useful cutting tools, and actually preferred as cutting tools in some archaeological contexts.

Springbok used in experimental archaeology

The springbok spear test. Figure S6D from Wilkins et al. 2012

I think the authors did a nice job of finding multiple ways to test the use of these points as spear tips. They examined edge wear to show that on these artifacts it is differentially concentrated near the tip. They shot a bunch of experimentally-produced tips into springbok carcasses, showing the pattern of wear that comes from use on a hafted spear, and this pattern matches the archaeological points. Furthermore, they show that experimental use of the points as cutting tools yields a different wear pattern, as does postdepositional damage to the artifacts. They find that some of the points are modified on the base, suggesting hafting, but do not report any evidence of glue or base wear that would have come from the wooden spear. A clever part of their analysis concerns the symmetry of the points. They expected that as a cutting tools is blunted and resharpened, the shape of the overall tool will become skewed, so smaller points should be less symmetrical. The archaeological points show the opposite pattern, with smaller points just as symmetrical as the large ones. The sizes of the points fall within the range of ethnographic and MSA spear points, not smaller projectiles such as arrows or atlatl darts.

So all in all, these look like good spear tips. This seems like yet another case where a more intensive investigation of the African record has shown that supposedly "advanced" toolmaking techniques were mastered by Middle Pleistocene humans. With some of the other techniques -- such as blade production -- people seem to show an effervescent pattern. A handful of sites show an early occurrence of the technique but no clear tradition carrying the early innovation into later time periods. Maybe hafting is another such case, a relatively complex innovation that was repeatedly reinvented, with people repeatedly falling back to the simpler option (in this case, sharpened wood spears without points).

The archaeological record may be giving us a signal of the importance of communication and knowledge accumulation relative to innovation in our prehistory. But to be clear about this will require a fuller record, with fewer blank spots.