The missing <i>Myopus</i>:plugging the gaps in Late Pleistocene small mammal identification in western Europe with geometric morphometrics

15 pagesInternational audienceLemmus and Myopus are two lemming species with distinct habitat requirements but which show very similar dental morphologies. They are thus extremely difficult to distinguish from one another in the fossil record on the basis of their dental remains, leading to poor understanding of the palaeobiogeographical evolution of Myopus as well as inaccurate palaeoenvrionmental reconstructions. Currently, the presence of Myopus in the fossil register from the Pleistocene is still debated and no firm occurrence of this lemming in western Europe has yet been confirmed for the Late Pleistocene. In this paper, we used geometric morphometrics on modern material to establish morphological differences between Lemmus and Myopus teeth (first lower and third upper molars). Morphological data were then used to build a robust linear discriminant model able to confidently classify isolated teeth of these two genera, and finally, linear discriminant models were used on fossil remains of Lemmus/Myopus from two Late Pleistocene archaeological/palaeontological sites (Grotte des Gorges and Gully Cave). This study demonstrates, for the first time, the presence of Myopus schisticolor in west European Late Pleistocene sites between the end of Marine Isotope Stage 3 and the beginning of the Holocene, during climatic events that favoured the development of taiga forest of birch and pine in these regions

Allogenic controls on the cyclicity on the continental sedimentation in the Guadix Basin (Betic Cordillera, Spain) throughout Pliocene and Pleistocene: state of the art

La Cuenca de Guadix (Cordillera Bética, S de España) constituye un escenario ideal para el estudio de los procesos auto- y alogénicos que influyen en la sedimentación continental en cuencas hidrológicamente cerradas. La extensión y continuidad lateral y vertical de los afloramientos y la presencia de numerosos yacimientos arqueológicos y paleontológicos en la zona han permitido interpretar cómo evolucionó la cuenca durante los últimos 4 Ma, y qué factores influyeron en dicha evolución. Estos estudios cobran una mayor importancia al permitir la caracterización de los paleoambientes que constituyeron el hábitat de los primeros pobladores de Europa. En el presente trabajo se muestra una síntesis de los estudios estratigráficos, sedimentológicos, petrológicos y paleoclimáticos más destacados desarrollados en los últimos años en la Cuenca de Guadix y los resultados más novedosos respecto a los controles alogénicos que determinaron la sedimentación continental en la cuenca.The Guadix Basin (Betic Cordillera, S Spain) is the ideal scenario to study the auto- and allogenic processes controlling continental sedimentation in hydrologically closed-basins. The extension and the lateral and vertical continuity of the outcrops, together with abundant archaeological and palaeontological sites in the area, have allowed the interpretation of the evolution of the basin throughout the last 4 Ma and the factors controlling it. These studies become much more important due to their relation to the characterisation of palaeoenvironments inhabited by the first European hominins. In this work, we present a synthesis of the most significative stratigraphical, sedimentological, petrological and palaeoclimatic studies developed in the Guadix Basin in the last decade, and updated results regarding the allogenic factors that controlled the continental sedimentation in the basin.El presente estudio ha sido financiado por el Proyecto CGL2009-07830/BTE (MICINN-FEDER), los Grupos de Investigación RNM-369 y RNM-200 del Plan Andaluz de Investigación y por el ProyectoAHOB-3 (Leverhulme Trust Foundation)

Scales of analysis : evidence of fish and fish processing at Star Carr

This contribution directly relates to the paper published by Wheeler in 1978 entitled ‘Why were there no fish re- mains at Star Carr?’. Star Carr is arguably the richest, most studied and re-interpreted Mesolithic site in Europe but the lack of fish remains has continued to vex scholars. Judging from other materials, the preservation conditions at the site in the late 1940s/early 1950s should have been good enough to permit the survival of fish remains, and particularly dentaries of the northern pike (Esox lucius L., 1758) as found on other European sites of this age. The lack of evidence has therefore been attributed to a paucity of fish in the lake. However, new research has provided multiple lines of evidence, which not only demonstrate the presence of fish, but also provide evidence for the species present, data on how and where fish were being processed on site, and interpretations for the fishing methods that might have been used. This study demonstrates that an integrated approach using a range of methods at landscape, site and microscopic scales of analysis can elucidate such questions. In addition, it demonstrates that in future studies, even in cases where physical remains are lacking, forensic techniques hold significant potential

Middle and Late Pleistocene environmental history of the Marsworth area, south-central England

To elucidate the Middle and Late Pleistocene environmental history of south-central England, we report the stratigraphy, sedimentology, palaeoecology and geochronology of some deposits near the foot of the Chiltern Hills scarp at Marsworth, Buckinghamshire. The Marsworth site is important because its sedimentary sequences contain a rich record of warm stages and cold stages, and it lies close to the Anglian glacial limit. Critical to its history are the origin and age of a brown pebbly silty clay (diamicton) previously interpreted as weathered till. The deposits described infill a river channel incised into chalk bedrock. They comprise clayey, silty and gravelly sediments, many containing locally derived chalk and some with molluscan, ostracod and vertebrate remains. Most of the deposits are readily attributed to periglacial and fluvial processes, and some are dated by optically stimulated luminescence to Marine Isotope Stage (MIS) 6. Although our sedimentological data do not discriminate between a glacial or periglacial interpretation of the diamicton, amino-acid dating of three molluscan taxa from beneath it indicates that it is younger than MIS 9 and older than MIS 5e. This makes a glacial interpretation unlikely, and we interpret the diamicton as a periglacial slope deposit. The Pleistocene history reconstructed for Marsworth identifies four key elements: (1) Anglian glaciation during MIS 12 closely approached Marsworth, introducing far-travelled pebbles such as Rhaxella chert and possibly some fine sand minerals into the area. (2) Interglacial environments inferred from fluvial sediments during MIS 7 varied from fully interglacial conditions during sub-stages 7e and 7c, cool temperate conditions during sub-stage 7b or 7a, temperate conditions similar to those today in central England towards the end of the interglacial, and cool temperate conditions during sub-stage 7a. (3) Periglacial activity during MIS 6 involved thermal contraction cracking, permafrost development, fracturing of chalk bedrock, fluvial activity, slopewash, mass movement and deposition of loess and coversand. (4) Fully interglacial conditions during sub-stage 5e led to renewed fluvial activity, soil formation and acidic weathering