Middle Pleistocene Lithic Industry and Hominin Behavior at Laetoli

Resumo

Traditionally, insights into hominin technology, behaviours and activities are mostly inferred from the analysis of stone artifacts. Cognition, once thought to be determined by brain size and complexity alone, can now also be measured by examining the relationships between core reduction strategies, tool types and lithic raw material utilizations and procurement strategies. The objectives of this study are to define the lithic industry and determine hominin behaviours, activities and cognition as reflected by the stone artifacts collected from the Middle Pleistocene upper Ngaloba Beds at Laetoli, Tanzania. The upper Ngaloba Beds, dated to about 200 kya have also yielded a cranium of Early Homo sapiens (EHs: referred to as Laetoli Hominin 18, LH18) or Homo heidelbergensis, in direct association with stone artifacts. The study reveals that the upper Ngaloba Beds’ stone tools represent a predominantly (93.840 %) light-duty toolkit (scrapers, becs, burins and points) mixed with a lower percentage (6.16 %) of heavy-duty toolkit (core/ large scrapers, bifaces/picks and core axes). This combination of light-duty and heavy-duty toolkits is best described as Early Middle Stone Age (EMSA) Ngaloban industry. Analysis of lithic raw materials shows that EHs at Laetoli utilized both local and non-local materials indicating wide-ranging patterns. Therefore, during 200 kya, EHs at Laetoli had a thorough knowledge of the landscape, using it to find and transport lithic raw materials. Moreover, analyses of stone artifact size, tool types and core utilizations versus lithic raw materials show that EHs knew how to manipulate lithic materials  to the best of their abilities. The occurrences of
retouched and Levallois points in general and some with thinned bulbs signals that EHs at Laetoli had knowledge of projectile weaponry and hafting systems.
Moreover, the presence of red ochre indicates procurement and use of pigments and therefore, evidence for symbolic behaviour by EHs during
EMSA at Laetoli, 200 kya.

Key-words: Ngaloba Beds – Early-Middle Stone Age – Laetoli – Tanzania