La séquence des rongeurs (Mammalia) des sites du Pléistocène inférieur et moyen d' Atapuerca (Burgos, Espagne)

Abstract

The Rodent sequence (Mammalia) of the Lower to Middle Pleistocene sites of Atapuerca (Burgos, Spain). The Sierra the Atapuerca has several Early to Middle Pleistocene localities related with a karst system. A railway trench exposes some of the cave deposits that have an excellent record of fossil humans, large and small mammals and other vertebrates, as well as an important Lithic industry of Modes 1 to 3. Some of these caves are: Trinchera Dolina, Trinchera Galería, Trinchera Elefante and Sima de los Huesos. In this paper we expose our results obtained from the study of the small mammals from the Atapuerca sites. The Gran Dolina or Trinchera Dolina is stratigraphically the longest sequence (18m), and it is divided in 11 stratigraphical levels, from bottom TD1, to top TD11. They belong to different chronological periods of Early and Middle Pleistocene age. The uppermost levels of Gran Dolina (TD11, TD10 and TD8b) contain Middle Pleistocene (post-Cromerian) micromammal assemblages: Arvicola, diverse and modern Microtus Terricola species, and Pliomys lenki. The lowermost levels (TD3 to TD6) contain late Early to early Middle Pleistocene mammals: Allophaiomys, Mimomys savini, primitive Microtus, Stenocranius, Terricola and, Pliomys episcopalis species. TD8a contains a scarce association of wet and open country faunas as Microtus related to the M. cf. oeconomus-ratticepoides. The level TD7 (between TD 6 and TD8a), records the Matuyama/Brunhes paleomagnetic reversal, and it has few fossil remains. Levels TD1, 2 and 9 are sterile in fossil contents. The level TD6 has record one of the earliest Homo species of Europe: Homo antecessor. The Trinchera Galería complex has been divided into five clastic fill phases (GI to GV) with twelve human living floors (GSU1-12) and it have yielded also human remains. The lower levels represent a more intense occupation of the cave by humans, yielding many stone tools and herbivore bones. Rodents from this site are characteristic of the Middle Pleistocene, (11 species): Arvicola aff. sapidus, Microtus jansoni, Microtus aff. arvalis, Terricola atapuerquensis, Iberomys brecciensis, Pliomys lenki, Allocricetus bursae, Apodemus sp., Eliomys quercinus quercinus, Marmota sp., Hystrix (Acanthion) vinogradovi. The Trinchera Elefante red lower unit has some rodents in common to the lower levels of Trinchera Dolina (TD3–TD6) as Allophaiomys chalinei, Iberomys huescarensis, Pliomys episcopalis and some of them are new to the Atapuerca record of small mammals : Ungaromys nanus, Castillomys rivas, Eliomys sp., Mimomys sp. and Allophaiomys lavocati. Small mammals from the upper units are still under study. The Sima de los Huesos site, well known by the well preserved, anatomically complete association of fossil human remains of Homo heidelbergensis, has very few fossils of small vertebrates: Allocricetus bursae; Apodemus sylvaticus; Pliomys lenki relictus; Microtinae indet.; Eliomys quercinus., the cave bats Rhinolophus mehelyi; Myotis myotis/M. blythi and Miniopterus schreibersi; some insectivores belonging to the genus Crocidura sp., some fish vertebrae and teeth ( Salmo sp. and Leuciscus sp.) and undetermined small reptile bones. Fragments of gasteropods, arthropods, charophytes and plant remains are also present.