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Bone diagenesis is a complex process that modifies bone components in response to burial conditions. These modifications help to understand deposit formation and classify fossils by stratigraphy. The combined techniques of X-ray diffraction with Rietveld refinement and infrared spectroscopy were used to study the bone diagenetic processes along the complete stratigraphic sequence of Galería site (Sierra de Atapuerca, Spain). Eleven chemometric indices considering the different bone components (phosphates, carbonates, organic phase), together with the apatite unit cell parameters and cell volume were evaluated by 9 machine learning algorithms for bone diagenesis/stratigraphic classification. The results showed differences along the stratigraphic sequence due to changes in the apatite structure chemistry (i.e., F - and OH - ), producing a gradual shift of the unit cell volume (from 531.9 to 526.1 Å 3 ) from GII to GIV associated with coupled dissolution-precipitation processes. Two diagenetic pathways are indicated: The lowest unit (GII) is characterized by leaching and carbonate loss in bone, suggesting an acidic and wet burial environment with the formation of authigenic phosphate minerals. The uppermost units (GIII-GIV) show bone apatite undergoing F - and CO 3 incorporation, suggesting a slightly alkaline and drier environment. These differences enabled the development of classification models to understand deposit formation dynamics and also recontextualize dissociated fossil bones., Competing Interests: Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

This work examines the possible behaviour of Neanderthal groups at the Cueva Des-Cubierta (central Spain) via the analysis of the latter's archaeological assemblage. Alongside evidence of Mousterian lithic industry, Level 3 of the cave infill was found to contain an assemblage of mammalian bone remains dominated by the crania of large ungulates, some associated with small hearths. The scarcity of post-cranial elements, teeth, mandibles and maxillae, along with evidence of anthropogenic modification of the crania (cut and percussion marks), indicates that the carcasses of the corresponding animals were initially processed outside the cave, and the crania were later brought inside. A second round of processing then took place, possibly related to the removal of the brain. The continued presence of crania throughout Level 3 indicates that this behaviour was recurrent during this level's formation. This behaviour seems to have no subsistence-related purpose but to be more symbolic in its intent., (© 2023. The Author(s).)