Olive diversity in Pompeii: morphometric analysis of fuel-derived charred stones (c. 50-79 CE) from two bakeries to trace regional production and dissemination of domesticated forms

The exceptional preservation of archaeological remains in the Vesuvian area offers a unique taphonomic window into Roman agricultural practices. This study presents a geometric morphometric analysis, using Elliptical Fourier Transforms (EFT), applied to an extensive dataset of charred olive stones ( Olea europaea L.) recovered from the combustion structures of two bakeries in Pompeii. Rather than focusing exclusively on urban consumption, these fuel-derived bio-archives, accumulated during the final decades of the city's occupation (c. 50–79 CE), provide crucial insights into regional agrosystems and ancient cultivar diversity. To evaluate ancient agrobiodiversity, well-preserved charred archaeological stones were compared against a comprehensive modern reference collection representing diverse Mediterranean morphotypes. Statistical analyses reveal high morphometric diversity within the bakeries, characterized by several distinct morphotypes. The material displays strong morphological affinities with modern varieties known for specialized uses (including oil production, table olives, and dual-purpose profiles), alongside a notable proportion of stones compatible with wild or feral phenotypes. These results suggest a sophisticated regional sourcing network, likely connected to Campanian villae rusticae , where olive pressing waste (pomace) was recycled as an engineered fuel source for urban workshops. Beyond its local implications for Pompeian economic networks, this study demonstrates the efficiency of geometric morphometrics on charred stones to trace local production setups, reconstruct ancient biogeographic dissemination histories, and document the complex landscape exploitation strategies of the Roman Mediterranean.