Robin DENNELL^1*, María MARTINÓN-TORRES², José María BERMÚDEZ DE CASTRO²

1. Department of Archaeology, Northgate House, University of Sheffield, Sheffield S102TN UK; 2. National Research Center for Human Evolution (CENIEH), Burgos 09002 Spain

FIRST PARAGRAPH: In a recent paper [1], we attempted to explain how how the variability of the fossil hominin sample in Early and Middle Pleistocene Europe could be largely explained as a result of repeated population dispersals, fragmentation, and re-combinations of surviving populations inside Europe in response to both long-term (Milankovich-length) and shorter, millennia-length (sub-Milankovich) climatic fluctuations, and also as a result of repeated episodes of immigration from Southwest Asia. We proposed a model based on population “sinks” and “sources”: “source” populations would have lived in those parts of southern Europe where hominins could have survived glacial periods, and “sink” populations would have been those where occupation was possible in temperate and interglacial intervals, such as in northern Europe. Spain and Britain are two examples of where “source” and “sink” populations may have been located. On our model, many “sink” populations would have become extinct when environmental conditions deteriorated. We suggested that local extinctions outside refugia would have been frequent, as an alternative to an “ebb and flow” model in which groups retreated to refugia when conditions worsened. In extreme situations (such as the maxima of glacial periods, when populations were at their lowest), even southern Europe may have been a population “sink” that was replenished from source populations in Southwest Asia.