Objectifying processes: The use of geometric morphometrics and multivariate analyses on Acheulean tools

2020-03-11T12:19:32+00:00

Nowadays, the fruitful discussion regarding the morphological variability of handaxes during the Middle Pleistocene has reached a decisive moment with the use of more accurate statistical methods, such as geometric morphometrics (GM) and multivariate analyses (MA). This paper presents a preliminary methodological approach for checking the utility of these new approaches on the analysis of the tools’ shape. It goes beyond the simple description of morphology and isolates the variables which define the final morphology of a tool. We compared two Middle Pleistocene sites, Boxgrove and Swanscombe, which are morphologically very different. Then, we applied the GM analysis on 1) 2D images, with two semi-landmark distributions: 28 semi-landmarks, specially concentrated on the tip and butt, and 60 equally spaced points; and 2) on 3D models using new software (AGMT3-D Software) including 5000 semi-landmarks. The more points used to define the tool’s outline, the more accurate will be the interpretation of the variables affecting shape. On the other hand, if the semi-landmarks are localized on specific sectors of the tool, a bias is created, by concentrating on those sectors, rather than the general tool shape. The 3D models offer a new dimension on the shape analysis, as their results mean the combination of plan-shape, profile-shape and the tool’s topography.

Using morphometrics to reappraise old collections: The study case of the Congo Basin Middle Stone Age bifacial industry

2020-03-11T14:38:11+00:00

Despite its strategic location within the continent, Central Africa is rarely integrated into the reconstruction of population dynamics during the Middle Stone Age (MSA) of Africa, especially in terms of the emergence, diffusion and behavioural patterns of Homo sapiens. However, hundreds of sites have been discovered in Central Africa during the 20th century and attributed to the Lupemban, one of the main MSA technological complexes of the region. This complex is mainly characterised by typological criteria based on the numerous bifacial pieces found in the Congo Basin and interpreted as an adaption to the rainforest environment. Most of these Lupemban assemblages have not been studied for decades and thus it is particularly difficult to assess their diversity. This paper presents a detailed combined morphometrical approach (linear measurements and indices, Log Shape Ratio, Elliptic Fourier Analysis) to take a fresh and rigorous look at the Lupemban bifacial tools. We discuss the comparison of different morphometrical approaches to deal with “old” collections for which contexts, particularly chronological ones, are partially missing. We present the results of this approach on three assemblages of bifacial pieces gathered in the 1930s and late 1960s. We quantify their variability and discuss not only their homogeneity but also the variation of a Lupemban hallmark, namely the “Lupemban point”.

Journal of Lithic Studies

Objectifying processes: The use of geometric morphometrics and multivariate analyses on Acheulean tools

Using morphometrics to reappraise old collections: The study case of the Congo Basin Middle Stone Age bifacial industry