A new method of three-dimensional morphometry for analyzing the functional potentialities of bifaces. Contribution to the study of artefacts from AU P3 from the “Caune de l’Arago” (France)

Techno-functional and 3D shape analysis applied for investigating the variability of backed tools in the Late Middle Paleolithic of Central Europe

“…Concerning the intersection between upper surface and cutting edge, Keilmesser record a convex or slightly convex profile that is halfway between backed flakes and backed scrapers. This data fits well with the presumed functionality of Keilmesser [ 9 , 67 , 113 ], since extremely convex and asymmetric bevel related to angles > 60° seem to be the prerogatives of scraping tools, while more flat, symmetrical or slightly asymmetrical bevel should be predisposed for cutting related to longitudinal motion [ 93 , 95 , 99 , 114 , 115 ]. However, it is evident also in this case that a quite internal variability is recognized in each tool type, and the morpho-techno-functional features of the Keilmesser overlap in most cases with those of scrapers and, in lesser extent, of simple flakes.…”

“…In the next step, automated morphological analysis were applied on the 3D models of the artefacts. This approach has been developed in the last years, and successfully used in the analysis of bifacial tools in a growing number of case studies [62,[98][99][100]. Shape statistical analysis were carried out with the software AGMT-3D, which has the advantage of performing several steps automatically [101].…”

“…The comparison of the tools' cutting edge, instead, provides the most interesting element, if related to their functional implications. The cutting edge angles and bevel are indirect indicators of functionality, penetrative potential and movement of use [93,99,112]. A strong consistency is noticed when comparing the angles formed by the upper and lower surfaces on the cutting edge of Keilmesser and scrapers.…”

Torque creation and force variation along the cutting edges of Acheulean handaxes: implications for tip thinning, resharpening and tranchet flake removals

“…A series of authors (Roberts et al, 1997;Mitchell, 1996;Bello et al, 2009;García-Medrano et al 2019) have linked this behaviour with the preferential creation and use of highly acute and sharp cutting edges in the distal portion of these tools. Key et al (2016) similarly link the more acute distal edges observed on handaxes more generally to their increased cutting ability (relative to proximal edges), while Viallet (2019) used relative acuteness to define 'active' cutting edges in the distal aspects of bifaces. Many others have also associated the modification and shaping of the distal edges of Acheulean handaxes with a utilitarian application (e.g., McNabb 1993, McNabb et al, 2004;Sharon, 2010;Beyene et al 2013, Moncel et al 2013; also see: Herzlinger and Goren-Inbar 2019).…”

“…Bifaces from other Acheulean sites similarly show a propensity towards proximal thinning and bulb of percussion removal that may be linked to cutting edge production and maintenance (e.g. White, 1998;Hosfield, 2011;de la Torre et al, 2014;Viallet, 2019). Some handaxes, including examples from Kalambo Falls (Clark et al, 2001), also display evidence of slight secondary 'point' or edge production on the butt.…”