Mid and Late Holocene population changes at the Sabana de Bogota (Northern South America) inferred from skeletal morphology and radiocarbon chronology

The human history of the Sabana de Bogota (SB) in Northern South America has been interpreted both as a continuous process of biocultural evolution and as a process of population discontinuities. Both hypotheses were evaluated on the basis of craniofacial morphology and radiocarbon evidence within a paleoenvironmental framework. The results suggest that the craniofacial morphology changed significantly over time. The investigation of the available radiocarbon database shows that there are hiatuses throughout the Holocene with a major gap between 4700 and 4100 C-14 BP, which is coincident with strong paleoenvironmental shifts. According to these results, a Population Discontinuity Model is presented which states that during the mid-Holocene (ca. 6000-3800 C-14 BP) population events as contraction/extinction and/or expansion/dispersals processes influenced by paleoenvironmental changes, promoted the almost complete depopulation of the SB, subsequently allowing the arrival of new hunter-gatherer populations from the Middle Magdalena Valley. Between ca. 2000-1500 C-14 BP, population expansions of agricultural societies from the east-northeast and/or from the Middle Magdalena Valley penetrated the SB and replaced the Herrera populations. The discontinuity scenario presented is compatible with the concepts of human biogeography and evolutionary geography. (C) 2011 Elsevier Ltd and INQUA. All rights reserved.