The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age.

The timing and location of the emergence of our species and of associated behavioural changes are crucial for our understanding of human evolution. The earliest fossil attributed to a modern form of Homo sapiens comes from eastern Africa and is approximately 195 thousand years old, therefore the emergence of modern human biology is commonly placed at around 200 thousand years ago. The earliest Middle Stone Age assemblages come from eastern and southern Africa but date much earlier. Here we report the ages, determined by thermoluminescence dating, of fire-heated flint artefacts obtained from new excavations at the Middle Stone Age site of Jebel Irhoud, Morocco, which are directly associated with newly discovered remains of H. sapiens. A weighted average age places these Middle Stone Age artefacts and fossils at 315 ± 34 thousand years ago. Support is obtained through the recalculated uranium series with electron spin resonance date of 286 ± 32 thousand years ago for a tooth from the Irhoud 3 hominin mandible. These ages are also consistent with the faunal and microfaunal assemblages and almost double the previous age estimates for the lower part of the deposits. The north African site of Jebel Irhoud contains one of the earliest directly dated Middle Stone Age assemblages, and its associated human remains are the oldest reported for H. sapiens. The emergence of our species and of the Middle Stone Age appear to be close in time, and these data suggest a larger scale, potentially pan-African, origin for both.

A worked bone assemblage from 120,000-90,000 year old deposits at Contrebandiers Cave, Atlantic Coast, Morocco.

The emergence of Homo sapiens in Pleistocene Africa is associated with a profound reconfiguration of technology. Symbolic expression and personal ornamentation, new tool forms, and regional technological traditions are widely recognized as the earliest indicators of complex culture and cognition in humans. Here we describe a bone tool tradition from Contrebandiers Cave on the Atlantic coast of Morocco, dated between 120,000-90,000 years ago. The bone tools were produced for different activities, including likely leather and fur working, and were found in association with carnivore remains that were possibly skinned for fur. A cetacean tooth tip bears what is likely a combination of anthropogenic and non-anthropogenic modification and shows the use of a marine mammal tooth by early humans. The evidence from Contrebandiers Cave demonstrates that the pan-African emergence of complex culture included the use of multiple and diverse materials for specialized tool manufacture.

Reconstructing Late Pleistocene paleoclimate at the scale of human behavior: an example from the Neandertal occupation of La Ferrassie (France).

Exploring the role of changing climates in human evolution is currently impeded by a scarcity of climatic information at the same temporal scale as the human behaviors documented in archaeological sites. This is mainly caused by high uncertainties in the chronometric dates used to correlate long-term climatic records with archaeological deposits. One solution is to generate climatic data directly from archaeological materials representing human behavior. Here we use oxygen isotope measurements of Bos/Bison tooth enamel to reconstruct summer and winter temperatures in the Late Pleistocene when Neandertals were using the site of La Ferrassie. Our results indicate that, despite the generally cold conditions of the broader period and despite direct evidence for cold features in certain sediments at the site, Neandertals used the site predominantly when climatic conditions were mild, similar to conditions in modern day France. We suggest that due to millennial scale climate variability, the periods of human activity and their climatic characteristics may not be representative of average conditions inferred from chronological correlations with long-term climatic records. These results highlight the importance of using direct routes, such as the high-resolution archives in tooth enamel from anthropogenically accumulated faunal assemblages, to establish climatic conditions at a human scale.

The mammalian fauna associated with an archaic hominin skullcap and later Acheulean artifacts at Elandsfontein, Western Cape Province, South Africa.

The Elandsfontein site, Western Cape Province, South Africa, is well known for an archaic hominin skullcap associated with later Acheulean artifacts. The site has also provided nearly 13,000 mammalian bones that can be identified to skeletal part and taxon. The assemblage derives from 49 species, 15 of which have no historic descendants. Comparisons to radiometrically dated faunas in eastern Africa indicate an age between 1 million and 600 thousand years ago. Unique features of the fauna, including the late occurrence of a dirk-toothed cat and a sivathere, may reflect its geographic origin in a region that was notable historically for its distinctive climate and high degree of biotic endemism. Together, taxonomic composition, geomorphic setting, and pollen extracted from coprolites indicate the proximity of a large marsh or pond, maintained by a higher water table. The small average size of the black-backed jackals implies relatively mild temperatures. The sum of the evidence places bone accumulation during one of the mid-Pleistocene interglacials that were longer and cooler than later ones, including the Holocene. The geomorphic context of the fauna presents no evidence for catastrophe, and most deaths probably resulted from attritional factors that disproportionately killed the young and old. However, only the dental-age profile of long-horned buffalo supports this directly. Field collection methods biased skeletal-part representation, but originally, it probably resembled the pattern in the younger, marsh-edge Acheulean occurrence at Duinefontein 2, 45 km to the south. Excavation there exposed multiple vertebral spreads, which probably mark carcasses from which hominins or large carnivores removed the meatier elements. Bone damage at both sites suggests that, despite abundant artifacts, hominins were much less important than carnivores in the bone accumulation. Together with limited observations from other sites, Elandsfontein and Duinefontein provisionally suggest that Acheulean-age hominins obtained few large mammals, whether by hunting or scavenging.