The Neolithic people are thought to have introduced new burial rituals - including megalithic tombs, which were used over an extended period of time as sites for collective burials and ritual acts. Complex patterns of treating and reburying skeletal remains have been identified in some tombs.
     The analysis of the human remains from the strikingly situated 3 metre diameter tomb at Alto de Reinoso, 250 kilometres north of Madrid, represents the widest integrative study of a Neolithic collective burial in Spain - a good example of a non-megalithic barrow. Combining archaeology, osteology, molecular genetics, and stable isotope analysis, the study provides information on the number of individuals, as well as their age, sex, body height, diseases, injuries, mitochondrial DNA profiles, kinship relations, mobility, and diet.
     The grave was in use for approximately one hundred years around 3700 BCE - the Late Neolithic in Iberia. Findings suggest the tomb probably began as a burial chamber made of wood, mud, and other organic materials, which was later dismantled and converted to a monumental structure by erecting a stone mound over it.
     The uppermost Bronze Age layer, containing the remains of two individuals from around 1700 to 1500 BCE and disturbed by agricultural activity, is not included in the study. Beneath that, further bodies represented a different use of the tomb, with almost all of those skeletons missing bones, especially skulls. At the bottom, on natural bedrock, six complete and six partial skeletons lay in crouched positions.
     In total the Neolithic burials comprise at least 47 individuals - a surprisingly high density - including males, females, and adolescents, although children aged 0 to 6 years were under-represented. The remains exhibit a moderate number of pathologies, such as degenerative joint diseases, healed fractures, head injuries, and tooth decay.
     Mitochondrial DNA profiles reveal a closely related local community with matrilineal kinship. In some cases adjacent individuals in the bottom layer showed familial relationships. According to their strontium isotope ratios, only a few were likely to have spent their early childhood in a different geological environment - the majority grew up locally. Carbon and nitrogen isotope analysis indicate a homogeneous group with egalitarian access to food. Cereals and small ruminants - possibly sheep and goats - were the principal sources of nutrition: a lifestyle typical of sedentary farming populations in the Spanish plateau during this period of the Neolithic.
     Artefacts were not abundant, but include both personal adornments such as stone necklace beads and wild boar tusk pendants, as well as grave goods such as polished stone axes, flint blades and microliths, and bone scrapers. There was a distinct lack of pottery in megalithic tombs, at least during the earlier period of their use.
     The Neolithic tombs in Europe represent a particular type of collective burial. Communal use clearly illustrates the bond within a community where the individual is not at the forefront, in life or in death. It was not until the Copper and Bronze Ages that social differentiation increased, and individuals and groups came to the fore.

Edited from Phys.org, Plos One (20 January 2016)