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10.1016/j.quascirev.2014.05.031 The first migration out of Africa undertaken by the genus Homo is documented in Georgia at 1.8 Myr (Dmanisi) and some 0.4 Myr afterwards in the Middle East (¿Ubeidiya). However, the debate on when the European continent was populated for the first time remains open. The first human presence in Europe prior to the Jaramillo subchron (1.07¿0.99 Myr) is evidenced at Fuente Nueva 3 and Barranco León D (Orce) and at Sima del Elefante (Atapuerca), an occupation that seems to have continued through the Jaramillo at Gran Dolina TD3¿4 and TD5 (Atapuerca), at Vallparadís (Barcelona), and up to the Matuyama¿Brunhes boundary at Gran Dolina TD6. Even so, those who still defend a `short chronology¿ espouse an intermittent early population limited to the Mediterranean area, delaying the first occupation until after the Jaramillo. These hypotheses fail to explain what factors were behind the absence of population in Europe prior to this period, bearing in mind that there were populations of hominins at the gates of Europe between 1 and 0.5 Myr before the first archaeological record documented in Western Europe. Paleomagnetic analyses of the archaeological sites are rarely able to detect the Jaramillo subchron due to its short duration, while the radiometric dating methods (U-series/ESR) usually applied are limited in the accuracy they can achieve for the chronologies in question. These limitations make it necessary to depend on the biostratigraphy of small and large mammals to ascertain with precision the time of the first colonization of the continent. Accordingly, in the present article we discuss the chronological data from the older Iberian archaeological sites using biostratigraphic data to establish an archaeological sequence that demonstrates the

The Sciuridae are the family of rodents that comprises all extant and fossil squirrels. In the Ramblian and especially in the Aragonian of the Tertiary basin of Calatayud-Montalbán (Aragón, Spain) the remains of Sciuridae are relatively abundant. A major problem solved in this paper is the distinction of Ml and M2, both in the upper and the lower dentition. Traditionally, in the literature these elements are treated as a unit Ml,2. We managed to separate them, on the basis of the study of material of two extant species, Atlantoxerus getulus and Sciurus vulgaris. In our study of the fossil Sciuridae from the Calatayud-Montalbán Basin 9 species were recognized, belonging to 6 genera: Heteroxerus rubricati, H. grivensis, Atlantoxerus idubedensis sp. nov., A. blacki, Aragoxerus ignis, Spermophilinus besana sp. nov., S. bredai, Freudenthalia daamsi sp. nov. y Palaeosciurus feignouxi. Aragoxerus and Freudenthalia are new genera. Atlantoxerus idubedensis sp. nov. is a small Atlantoxerus, similar to primitive Heteroxerus, and characterized by a reduced or absent anterior cingulum in M1, M2 and M3. Spermophilinus besana sp. nov. is the smallest Spermophilinus species known so far. In the lower teeth the anterolophid is separated from the protoconid by a deep furrow, and the entoconid is reduced or absent. Aragoxerus gen. nov. (tribe Xerini) contains only one species, A. ignis, formerly assigned to Heteroxerus. Although Aragoxerus is quite similar to Heteroxerus, its smaller size, simple dental pattern, absence of metaconule and anterior cingulum, and the lack of accessory ornamentations permit us to distinguish it as a separate genus. Freudenthalia gen. nov. is a monospecific genus of uncertain systematic position, tentatively placed in the tribe Sciurini. Freudenthalia daamsi sp. nov. is the only species of this genus. It is characterized by a metaloph completely fused to the protocone, a loop-shaped metaconule, and the absence of the entolophid. Within the genus Heteroxerus two pairs of names are synonimized: H. vireti is a synonym of H. ru