Geometric microliths are one of the most relevant and ubiquitous lithic technological adaptations of the Late Mesolithic in Westernmost Europe. At Muge shellmiddens, previous studies have revealed large amounts of variability in the morphology of these implements, especially the triangles. Three hypotheses have been suggested to explain morphological variability: 1) idiosyncratic cultural behavior across space and time; 2) successive application of maintenance retouch (Frison effect); 3) or the application of different morphologies for specific functionalities. Drawing upon recent developments on Geometric Morphometrics studies, this poster presents new data on the morphometric variability of geometric microliths from Cabeço da Amoreira, one of the largest shellmounds at Muge. Our goal is to test one of the three mentioned hypotheses, specifically the one that argues that identified subtypes are a consequence of discard at different points along a continuum of reduction. With this study, we expect to contribute to a better understanding of Mesolithic lithic technology and offer new interpretations to the economic and technological strategies of the last hunter-gatherer communities in the Western Atlantic facade of Iberia.