The small mammals of Sima del Elefante (Atapuerca, Spain) and the first entrance of Homo in Western Europe

Abstract

The small-mammal assemblages associated with the fossil human remains of the Sima del Elefante site provide the best tool for estimating the age for the first appearance of Homo during the Early Pleistocene of Western Eurasia. Sima del Elefante (TE) is part of the archaeo-palaeontological complex known as the Atapuerca cave-sites, in Burgos, Spain. In 2007, the lower levels of Sima del Elefante yielded the earliest European fossil of a Homo species from the level Trinchera Elefante 9c (TE9c). The site is an opening to the Galería Bajainfill, with 25 m of cave sediments ordered in 22 stratigraphic levels. The Lower Red Unit, TELRU, comprises the stratigraphic levels Trinchera Elefante 7 (TE7) to Trinchera Elefante 16 (TE16). The faunal association of the TELRU is composed of nearly one hundred species of vertebrates, including 17 species of amphibians and squamate reptiles, nearly 60 mammals (Homo sp. included), around 15 birds, and an indeterminate number of fishes. Only levels TE7 to TE14 yielded vertebrate fossil remains. The small-mammal assemblages of the TELRU display the same species composition from level TE7 to level TE14, though their ecological structure varies in the relative richness in number of specimens (Shannon). The species of small mammals from Sima del Elefante TELRU levels TE7 to TE14 are: the shrews Sorex sp.1, Sorex sp. 2, Asoriculus gibberodon, Beremendia fissidens, Crocidura kornfeldi; the talpids Galemys cf. G. kormosi and Talpa cf. T. europaea; the erinaceid Erinaceus cf. E. praeglacialis; the lagomorphs Oryctolagus cf. O. lacosti and Lepus cf. L. terraerubrae; the chiropters Miniopterus schreibersii, Myotis sp., Rhinolophus sp. and Chiroptera spp.; the rodents Sciurus sp., Castillomys rivas, Apodemus aff. A. sylvaticus, Allophaiomys lavocati, A. burgondiae, A. nutiensis, Arvicola jacobaeus, Ungaromys nanus, Pliomyscf. P. simplicior, Eliomys sp. and Castor sp. This faunal assemblage correlates levels TE7 to TE14 with other Western European localities that are biostratigraphically dated to a Late Villafranchian or Early Biharian age, localities such as Bagur 2, Fuente Nueva 3, Barranco León D, Le Vallonnet, Les Valerots, Courterolles and Monte Peglia, among others. These Late Villafranchian localities are situated in the late Matuyama, pre-Jaramillo palaeomagnetic zone, thus dating to around 1.5 to 1.2 Ma.