Introducing Lithikos 1 – A novel volumetric morphometric analyser via comparative analyses of Acheulean handaxe mirror asymmetry

• Introduces Lithikos , employing volumetrics as an alternative to traditional distance-based stone tool morphometry. • Lithikos aligns the analytical metrics with the three-dimensional nature of material forms. • Lithikos synthesises a radially symmetrical reference mesh to measure bilateral and bifacial handaxe asymmetry. • Unlike GMA’s linear coefficients, Lithikos reveals significantly greater bifacial than bilateral asymmetry across assemblages. • Lithikos uncovers intriguing morphometric relationships previously opaque to linear coefficients. This article introduces Lithikos , an open-access morphometric application that uses volumetrics to offer a novel alternative to traditional linear approaches in stone tool morphometry. Lithikos presents an innovative approach to parsing the spatial complexity of solid objects by aligning its analytical metrics with the three-dimensional nature of material forms. Unlike traditional distance-based and preceding unreferenced volumetric methods, Lithikos captures multifaceted shape variance by synthesising a reference mesh to identify, isolate, and remove radially symmetrical volume before quantifying bilateral and bifacial mirror asymmetry. A pilot study of 399 handaxes from five Levantine Acheulean assemblages demonstrates that these referenced volumetric coefficients may achieve greater accuracy, sensitivity, and practical utility than traditional metrics during analyses of handaxe mirror asymmetry. In this study, Lithikos reveals significantly greater bifacial than bilateral asymmetry across assemblages — diametrically opposing the relationship reported by recent distance-based approaches — while uncovering intriguing morphometric relationships such as an axis of equivalent orthogonal asymmetry previously opaque to linear coefficients.