Els Cornelissen

Human Responses to Changing Environments in Central Africa Between 40,000 and 12,000 B.P.

Reconstructions of the Equatorial forest in Central Africa fuel the debate on whether hunter-gatherers at the end of the Pleistocene were capable of living in or off the forest prior to the advent of agriculture. Their traces are rare and often reduced to their stone equipment. In an attempt to see to what extent technology and environmental exploitation are interrelated, all Central African sites dated between 40,000 and 12,000 B.P. are analyzed for their material culture, the environmental setting at the time of the occupation, and the exploitation of that environment. Although the evidence is still circumstantial, two large technological traditions have been recognized in Central Africa at the end of the Pleistocene, the Lupemban and microlithic industries, and both are associated with a variety of environments. This, in combination with a fragmented forest and concomitant increase of ecotone during the Last Glacial Maximum, would have enhanced rather than hampered human occupation in the area. It may be argued that the inherent flexibility and capability of exploiting a variety of environments enabled the hunter-gatherer communities to face and adapt to environmental changes regardless of stone technology.

First early hominin from central Africa (Ishango, Democratic Republic of Congo).

Despite uncontested evidence for fossils belonging to the early hominin genus Australopithecus in East Africa from at least 4.2 million years ago (Ma), and from Chad by 3.5 Ma, thus far there has been no convincing evidence of Australopithecus, Paranthropus or early Homo from the western (Albertine) branch of the Rift Valley. Here we report the discovery of an isolated upper molar (#Ish25) from the Western Rift Valley site of Ishango in Central Africa in a derived context, overlying beds dated to between ca. 2.6 to 2.0 Ma. We used µCT imaging to compare its external and internal macro-morphology to upper molars of australopiths, and fossil and recent Homo. We show that the size and shape of the enamel-dentine junction (EDJ) surface discriminate between Plio-Pleistocene and post-Lower Pleistocene hominins, and that the Ishango molar clusters with australopiths and early Homo from East and southern Africa. A reassessment of the archaeological context of the specimen is consistent with the morphological evidence and suggest that early hominins were occupying this region by at least 2 Ma.

The Later Pleistocene in the Northeastern Central African Rainforest

The reconstruction of Late Pleistocene population dynamics in the northeastern Central African rainforest is hampered by the scanty though intriguing environmental, archaeological, and human fossil records. The few well documented and dated sites combined with undated surface finds in museum collections are examined for patterning in their spatial, temporal, and technological distribution. The results are ambiguous and point to both continuity and discontinuity in occupation of forested environments prior to, during, and after MIS 2. Particularly striking is the absence of quartz microlithic industries or any Later Stone Age (LSA) assemblages in the western part of the region. This may be due to lack of suitable raw materials or low visibility of quartz scatters encountered during informal surveys. At the same time the analysis suggests potentially interesting avenues for future research. These include, for example, the role that riverine systems might have played in the patterning of both prehistoric and extant genetic relationships. Utilization of archaeologically perishable bone in lithic poor regions may also account for apparently disjunctive archaeological distributions.