Identifying Middle Paleolithic Residential Units Through the Spatial Organization of Combustion Structures at Abric Romaní (Barcelona, Spain)

The habitual and controlled use of fire among Neanderthal groups, together with the residential use of caves and rock shelters, represents a major turning point in the emergence of Paleolithic camp bases. In Middle Paleolithic sites, the interrelation between shelter geomorphology, fire-use locations and activity areas has been interpreted as evidence of spatial organization. Hearths are, therefore, valuable for investigating site structure. The Abric Romaní offers an exceptional case study due to the preservation and extensive excavation strategy of numerous combustion structures across several archaeological units. This study analyses fire-use spatial organization in units Nb, Oa, Ob, P, Qa and R (ca. 60–54 ka) to explore how Neanderthals structured their living spaces. Using spatial statistical methods (i.e., covariate analysis, spatial modelling, and mark analysis), we evaluate the influence of distance from the back wall on fire-use location and distribution. We then isolate this effect to examine micro-scale patterns and compare the morphological and functional characteristics of combustion structures between wall-adjacent and wall-distanced sectors and across the archaeological sequence. Our findings show a relationship between fire-use locations and the back wall, defining preferential zones for fire placement. Fire use reflects a structured spatial zoning, separating combustion structures in sleeping and resting areas from those in communal activity areas. The morphology of combustion structures remained stable across units, while fire use varied flexibly within a stable spatial framework. Overall, these findings suggest that late Neanderthal occupations at Abric Romaní exhibited structured spatial cultural patterns comparable to those documented in modern hunter-gatherer campsites.