César Laplana

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

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 Galeria, 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 Galeria 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.

Rodents and insectivores from the late Miocene of Romerales (Fortuna Basin, Southern Spain)

Abstract The Neogene Fortuna Basin (Murcia Region, SE Spain) is rich in microvertebrate sites. Its continental sections include localities extended from the middle Turolian (MN12) to the early Ruscinian (MN14). However, there are few works dealing with the taxonomy of these fossil assemblages. In this paper we provide a complete taxonomic study of the rodents and insectivores from three levels (ROM-2B, ROM-2C and ROM-3A) within the Romerales section. We infer a late Turolian age (late Messinian) for these levels, among which the richest and most diverse level is ROM-C, including at least 11 different taxa. In addition, the paleoecological analysis of these fossil assemblages suggests the dominance of open herbaceous meadows under temperate climate during the formation of these sites, with a slight decrease in temperature and humidity from ROM-2B to ROM-2C.

Rodents from Baza-1 (Guadix-Baza Basin, southeast Spain): filling the gap of the early Pliocene succession in the Betics

ABSTRACT The Guadix-Baza Basin (Granada, southern Spain) represents one of the best continental records from the late Miocene to the middle Pleistocene in western Europe, but stratigraphic gaps are present in the early Pliocene due to the scarcity of sites from this time. In this article, rodent fossils from the locality of Baza-1 are described, providing new information on a time interval that was previously poorly known. The assemblage includes representatives of the genera Ruscinomys, Apocricetus, Stephanomys, Apodemus, Castillomys, Paraethomys, Occitanomys, Eliomys, Debruijnimys, and Trilophomys, an association that indicates an early Ruscinian age (MN14). A paleoecological analysis indicates that the Guadix-Baza Basin landscape during the early Pliocene was dominated by open herbaceous habitat under warm and dry climatic conditions. Our results contribute to the continuity of the stratigraphic record from the Betic Mountain range.

How Far into Europe Did Pikas (Lagomorpha: Ochotonidae) Go during the Pleistocene? New Evidence from Central Iberia

This paper reports the first find of pika remains in the Iberian Peninsula, at a site in central Spain. A fragmented mandible of Ochotona cf. pusilla was unearthed from Layer 3 (deposited some 63.4±5.5 ka ago as determined by thermoluminescence) of the Buena Pinta Cave. This record establishes new limits for the genus geographic distribution during the Pleistocene, shifting the previous edge of its known range southwest by some 500 km. It also supports the idea that, even though Europe’s alpine mountain ranges represented a barrier that prevented the dispersal into the south to this and other taxa of small mammals from central and eastern Europe, they were crossed or circumvented at the coldest time intervals of the end of the Middle Pleistocene and of the Late Pleistocene. During those periods both the reduction of the forest cover and the emersion of large areas of the continental shelf due to the drop of the sea level probably provided these species a way to surpass this barrier. The pika mandible was found accompanying the remains of other small mammals adapted to cold climates, indicating the presence of steppe environments in central Iberia during the Late Pleistocene.