The Variability of the Keilmesser-Concept: a Case Study from Central Germany

The bifacial Keilmesser is the type fossil of the late Middle Paleolithic Keilmessergruppen or Micoquian of central and eastern Europe. The tool is variable in shape but standardized regarding shaping sequences and morphological components. In this study we examine whether these components, a base and back opposite a sharp edge, are related only to bifacial tools or if they form a functional tool concept that was applied as well to simple edge retouched and to unifacially shaped flake tools. This study is based on a dataset of 29 3D-scanned artifacts from central Germany, for which the geographic origin, paleoenvironment, and chronological context are known in order to reduce variability introduced by these factors. With new luminescence dates, we can provide a chronological time frame for the collected and excavated artifacts to between 55 and 40 ka. We analyze variability caused by function, blank type, shaping, intensity of retouch, and typology, using 3D geometric morphometrics, Thickness Mapping, edge angle analysis, and multivariate principal component analysis based on conventional technological attributes and indices. We show that the unifacially shaped scrapers with a Keilmesser-like morphology can be classified as a unifacial variant of the bifacial Keilmesser. We interpret simple scrapers with a Keilmesser-like morphology as a special, simplistic variant of Keilmesser where the blank already fulfills the functional requirements of prehensile and active parts. With some caution related to sample size, an additional sample of Micoquian handaxes appears to be a related, but more symmetric tool concept in our data set.