Environmental Implications and Chalcolithic Ornamental Use of Marine Barnacle Shells Present in the Tholos of ‘La Pastora’ (Valencina de la Concepción, Sevilla, Spain)

The study of a set of marine arthropod shells from an archaeological excavation carried out in 1991–1992 in the tholos of La Pastora (Cooper Age Mega-site of Valencina-Castilleja, S Spain), has highlighted the environmental implications and ornamental use as beads not cited so far for this purpose. It is the barnacle species Chthamalus montagui Southward, 1976, of which are preserved 71 complete specimens. In this study a taxonomic analysis of these organisms is carried out, determining their classification and their physical and ecological characteristics, which make them especially suitable for this use. The interpretation is made regarding the environment in which these organisms were collected during the 3rd millennium BCE. Thus, it points towards a protected coastal area, but with a predominant marine influence, such as the wide marine bay that formed the mouth of the Guadalquivir River in those times. Finally, a radiocarbon analysis of one of these beads and two specimens of another species of barnacle collected in the rocks of the monument, provide a time range of 2760–2200 yr BCE. This range is consistent with the period of activity in the monument estimated by other authors.