Correction: Elephant bones for the Middle Pleistocene toolmaker.

[This corrects the article DOI: 10.1371/journal.pone.0256090.].

Elephant bones for the Middle Pleistocene toolmaker.

The use of bone as raw material for implements is documented since the Early Pleistocene. Throughout the Early and Middle Pleistocene bone tool shaping was done by percussion flaking, the same technique used for knapping stone artifacts, although bone shaping was rare compared to stone tool flaking. Until recently the generally accepted idea was that early bone technology was essentially immediate and expedient, based on single-stage operations, using available bone fragments of large to medium size animals. Only Upper Paleolithic bone tools would involve several stages of manufacture with clear evidence of primary flaking or breaking of bone to produce the kind of fragments required for different kinds of tools. Our technological and taphonomic analysis of the bone assemblage of Castel di Guido, a Middle Pleistocene site in Italy, now dated by 40Ar/39Ar to about 400 ka, shows that this general idea is inexact. In spite of the fact that the number of bone bifaces at the site had been largely overestimated in previous publications, the number of verified, human-made bone tools is 98. This is the highest number of flaked bone tools made by pre-modern hominids published so far. Moreover the Castel di Guido bone assemblage is characterized by systematic production of standardized blanks (elephant diaphysis fragments) and clear diversity of tool types. Bone smoothers and intermediate pieces prove that some features of Aurignacian technology have roots that go beyond the late Mousterian, back to the Middle Pleistocene. Clearly the Castel di Guido hominids had done the first step in the process of increasing complexity of bone technology. We discuss the reasons why this innovation was not developed. The analysis of the lithic industry is done for comparison with the bone industry.

Neandertals on the beach: Use of marine resources at Grotta dei Moscerini (Latium, Italy).

Excavated in 1949, Grotta dei Moscerini, dated MIS 5 to early MIS 4, is one of two Italian Neandertal sites with a large assemblage of retouched shells (n = 171) from 21 layers. The other occurrence is from the broadly contemporaneous layer L of Grotta del Cavallo in southern Italy (n = 126). Eight other Mousterian sites in Italy and one in Greece also have shell tools but in a very small number. The shell tools are made on valves of the smooth clam Callista chione. The general idea that the valves of Callista chione were collected by Neandertals on the beach after the death of the mollusk is incomplete. At Moscerini 23.9% of the specimens were gathered directly from the sea floor as live animals by skin diving Neandertals. Archaeological data from sites in Italy, France and Spain confirm that shell fishing and fresh water fishing was a common activity of Neandertals, as indicated by anatomical studies recently published by E. Trinkaus. Lithic analysis provides data to show the relation between stone tools and shell tools. Several layers contain pumices derived from volcanic eruptions in the Ischia Island or the Campi Flegrei (prior to the Campanian Ignimbrite mega-eruption). Their rounded edges indicate that they were transported by sea currents to the beach at the base of the Moscerini sequence. Their presence in the occupation layers above the beach is discussed. The most plausible hypothesis is that they were collected by Neandertals. Incontrovertible evidence that Neandertals collected pumices is provided by a cave in Liguria. Use of pumices as abraders is well documented in the Upper Paleolithic. We prove that the exploitation of submerged aquatic resources and the collection of pumices common in the Upper Paleolithic were part of Neandertal behavior well before the arrival of modern humans in Western Europe.

Hafting of Middle Paleolithic tools in Latium (central Italy): New data from Fossellone and Sant'Agostino caves.

Hafting of stone tools was an important advance in the technology of the Paleolithic. Evidence of hafting in the Middle Paleolithic is growing and is not limited to points hafted on spears for thrusting or throwing. This article describes the identification of adhesive used for hafting on a variety of stone tools from two Middle Paleolithic caves in Latium, Fossellone Cave and Sant'Agostino Cave. Analysis of the organic residue by gas chromatography/mass spectrometry shows that a conifer resin adhesive was used, in one case mixed with beeswax. Contrary to previous suggestions that the small Middle Paleolithic tools of Latium could be used by hand and that hafting was not needed since it did not improve their functionality, our evidence shows that hafting was used by Neandertals in central Italy. Ethnographic evidence indicates that resin, which dries when exposed to air, is generally warmed by exposure to a small fire thus softened to be molded and pushed in position in the haft. The use of resin at both sites suggests regular fire use, as confirmed by moderate frequencies of burnt lithics in both assemblages. Lithic analysis shows that hafting was applied to a variety of artifacts, irrespective of type, size and technology. Prior to our study evidence of hafting in the Middle Paleolithic of Italy was limited to one case only.

An abstract drawing from the 73,000-year-old levels at Blombos Cave, South Africa.

Depictive and abstract representations produced by drawing-known from Europe, Africa and Southeast Asia after 40,000 years ago-are a prime indicator of modern cognition and behaviour1. Here we report a cross-hatched pattern drawn with an ochre crayon on a ground silcrete flake recovered from approximately 73,000-year-old Middle Stone Age levels at Blombos Cave, South Africa. Our microscopic and chemical analyses of the pattern confirm that red ochre pigment was intentionally applied to the flake with an ochre crayon. The object comes from a level associated with stone tools of the Still Bay techno-complex that has previously yielded shell beads, cross-hatched engravings on ochre pieces and a variety of innovative technologies2-5. This notable discovery pre-dates the earliest previously known abstract and figurative drawings by at least 30,000 years. This drawing demonstrates the ability of early Homo sapiens in southern Africa to produce graphic designs on various media using different techniques.

From Neandertals to modern humans: New data on the Uluzzian.

Having thrived in Eurasia for 350,000 years Neandertals disappeared from the record around 40,000-37,000 years ago, after modern humans entered Europe. It was a complex process of population interactions that included cultural exchanges and admixture between Neandertals and dispersing groups of modern humans. In Europe Neandertals are always associated with the Mousterian while the Aurignacian is associated with modern humans only. The onset of the Aurignacian is preceded by "transitional" industries which show some similarities with the Mousterian but also contain modern tool forms. Information on these industries is often incomplete or disputed and this is true of the Uluzzian. We present the results of taphonomic, typological and technological analyses of two Uluzzian sites, Grotta La Fabbrica (Tuscany) and the newly discovered site of Colle Rotondo (Latium). Comparisons with Castelcivita and Grotta del Cavallo show that the Uluzzian is a coherent cultural unit lasting about five millennia, replaced by the Protoaurignacian before the eruption of the Campanian Ignimbrite. The lack of skeletal remains at our two sites and the controversy surrounding the stratigraphic position of modern human teeth at Cavallo makes it difficult to reach agreement about authorship of the Uluzzian, for which alternative hypotheses have been proposed. Pending the discovery of DNA or further human remains, these hypotheses can only be evaluated by archaeological arguments, i.e. evidence of continuities and discontinuities between the Uluzzian and the preceding and succeeding culture units in Italy. However, in the context of "transitional" industries with disputed dates for the arrival of modern humans in Europe, and considering the case of the Châtelperronian, an Upper Paleolithic industry made by Neandertals, typo-technology used as an indicator of hominin authorship has limited predictive value. We corroborate previous suggestions that the Middle-to-Upper Paleolithic transition occurred as steps of rapid changes and geographically uneven rates of spread.

The Acheulian and Early Middle Paleolithic in Latium (Italy): Stability and Innovation.

We present here the results of a technological and typological analysis of the Acheulian and early Middle Paleolithic assemblages from Torre in Pietra (Latium, Italy) together with comparisons with the Acheulian small tools of Castel di Guido. The assemblages were never chronometrically dated before. We have now 40Ar/39Ar dates and ESR-U-series dates, within a geomorphological framework, which support correlations to marine isotope stages. The Acheulian (previously correlated to MIS 9) is now dated to MIS 10 while the Middle Paleolithic is dated to MIS 7. Lithic analyses are preceded by taphonomic evaluations. The Levallois method of the Middle Paleolithic assemblage is an innovation characterized by the production of thin flake blanks without cortex. In contrast, the small tool blanks of the Acheulian were either pebbles or thick flakes with some cortex. They provided a relatively easy manual prehension. The choice of Levallois thin flake blanks in the Middle Paleolithic assemblage suggest that the new technology is most likely related to the emergence of hafting. Accordingly, the oldest direct evidence of hafting technology is from the site of Campitello Quarry in Tuscany (Central Italy) where birch-bark tar, found on the proximal part of two flint flakes, is dated to the end of MIS 7. Nevertheless, a peculiar feature of the Middle Paleolithic at Torre in Pietra is the continuous presence of small tool blanks on pebbles and cores and on thick flake albeit at a much lower frequency than in the older Acheulian industries. The adoption of the new technology is thus characterized by innovation combined with a degree of stability. The persistence of these habits in spite of the introduction of an innovative technique underlies the importance of cultural transmission and conformity in the behavior of Neandertals.

A Milk and Ochre Paint Mixture Used 49,000 Years Ago at Sibudu, South Africa.

Gas chromatography/mass spectrometry, proteomic and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) analyses of residue on a stone flake from a 49,000 year-old layer of Sibudu (South Africa) indicate a mixture of ochre and casein from milk, likely obtained by killing a lactating wild bovid. Ochre powder production and use are documented in Middle Stone Age South African sites but until now there has been no evidence of the use of milk as a binder. Our analyses show that this ochre-based mixture was neither a hafting adhesive nor a residue left after treating animal skins, but a liquid mixture consisting of a powdered pigment mixed with milk; in other words, a paint medium that could have been applied to a surface or to human skin. The significance of our finds also lies in the fact that it establishes the antiquity of the use of milk as a binder well before the introduction of domestic cattle in South Africa in the first millennium AD.

The Still Bay and Howiesons Poort at Sibudu and Blombos: Understanding Middle Stone Age Technologies.

The classification of archaeological assemblages in the Middle Stone Age of South Africa in terms of diversity and temporal continuity has significant implications with respect to recent cultural evolutionary models which propose either gradual accumulation or discontinuous, episodic processes for the emergence and diffusion of cultural traits. We present the results of a systematic technological and typological analysis of the Still Bay assemblages from Sibudu and Blombos. A similar approach is used in the analysis of the Howiesons Poort (HP) assemblages from Sibudu seen in comparison with broadly contemporaneous assemblages from Rose Cottage and Klasies River Cave 1A. Using our own and published data from other sites we report on the diversity between stone artifact assemblages and discuss to what extent they can be grouped into homogeneous lithic sets. The gradual evolution of debitage techniques within the Howiesons Poort sequence with a progressive abandonment of the HP technological style argues against the saltational model for its disappearance while the technological differences between the Sibudu and Blombos Still Bay artifacts considerably weaken an interpretation of similarities between the assemblages and their grouping into the same cultural unit. Limited sampling of a fragmented record may explain why simple models of cultural evolution do not seem to apply to a complex reality.