Evaluating possible metabolic stress in perinatal remains from 15th-century San Marcial de Rubicón: a multiproxy assessment of microporotic lesions

Objectives: This study evaluates diffuse microporotic lesions in two perinatal infants from San Marcial de Rubicón, the earliest European colonial settlement in the Canary Islands. We assess whether these lesions may reflect metabolic stress after controlling for post-depositional alteration in a harsh coastal and aeolian burial environment.,Materials and Methods: Ten individuals have been excavated from a newly identified cemetery at the site, including two perinates with widespread cortical porosity. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), radiographic studies, portable X-ray fluorescence (XRF), and computed tomography (CT) were used to characterize bone microstructure, elemental composition, sediment infilling, and the morphology of cortical alterations. These methods were applied to distinguish taphonomic features from microporosities potentially compatible with biological processes.,Results: SEM revealed abundant micropores and linear cortical disruptions, some containing angular sand grains. Elevated chlorine and sulfur concentrations in bone and sediment are consistent with prolonged exposure to marine aerosols and volcanic inputs, while CT density values confirmed substantial sediment infiltration. In UE11, the observed alterations are mainly consistent with aeolian abrasion, chemical dissolution, and sediment infilling. In UE25, however, a subset of micropores showed smoother and more rounded margins, with limited sediment association, making them less compatible with purely post-depositional abrasion.,Discussion and Conclusions: Perinatal bone immaturity and the extreme burial environment complicate the interpretation of microporotic lesions. However, once taphonomic overprinting is considered, a subset of lesions—particularly in UE25—remains compatible with metabolic stress during late gestation or the early postnatal period. This study highlights the value of integrated microanalytical approaches for evaluating early-life stress in fragile skeletal remains and for distinguishing environmental alteration from potential biological signals in perinatal bioarchaeology. More broadly, it provides rare evidence of infant health during the earliest stages of European colonial expansion in the Canary Islands, contributing to discussions on childhood vulnerability and the biological consequences of colonial frontier conditions.