31 research outputs found

    Amphibians and squamate reptiles from the latest early Pleistocene of Cueva Victoria (Murcia, southeastern Spain, SW Mediterranean): Paleobiogeographic and paleoclimatic implications

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    The karstic filling of Cueva Victoria in southeastern Spain, dated from the latest early Pleistocene (ca. 1.1 Ma), is famous for providing primate fossil remains (Theropithecus) of typical African origin, in the general controversy on the antiquity of the first hominid settlements in Western Europe and their possible entrance into Europe through the Strait of Gibraltar. Cueva Victoria has also furnished the following fauna of anurans and squamate reptiles: cf. Pelodytes sp. (Pelodytidae), Bufo cf. B. bufo (Bufonidae), Blanus cinereus (Blanidae), Tarentola sp. (Geckonidae), Chalcides cf. Ch. bedriagai (Scincidae), Timon cf. T. lepidus and indeterminate small lacertids (Lacertidae), Natrix maura, Coronella girondica, Rhinechis scalaris and Malpolon cf. M. monspessulanus (Colubridae). This faunal association seems to suggest a mean annual temperature slightly fresher than nowadays (approximately 1°C less than at present in the area), with cooler winters but warmer summers and above all higher mean annual precipitations (+ 400 mm). The landscape may correspond to an open forest environment of a Mediterranean type, with some still water points

    A new key locality for the Pliocene vertebrate record of Europe : the Camp dels Ninots maar (NE Spain)

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    A new Pliocene Konservat-Lagerstätte in north-eastern Spain is described here for the first time. It is referred to as Camp dels Ninots. The particular geological conditions of the site, which correspond to lacustrine sedimentation in a maar, made it ideal for the preservation of fossils. At present, five large mammal skeletons in anatomical connection have been recovered: three individuals of Alephis tigneresi, one of Stephanorhinus jeanvireti and one of Tapirus arvernenis, as well as isolated remains. A minimum of five individuals of the chelonian Mauremys leprosa have been recovered, some of them in anatomical connection. The rodent Apodemus atavus, the amphibians cf. Pleurodeles sp., Lissotriton aff. helveticus and Pelophylax cf. perezi and freshwater fishes (Leuciscus ?) complete the vertebrate assemblage uncovered up to the present time. The coexistence of Stephanorhinus jeanvireti and Alephis tigneresi suggests an age of about 3.2Ma for the Camp dels Ninots, near the MN15-MN16 transition. The Camp del Ninots fossil record enables one to extend the biogeographic range of some vertebrate taxa, such as Stephanorhinus jeanvireti, Tapirus arvernensis or Mauremys leprosa to the Iberian Peninsula. Taphonomic evidences of the skeletal remains indicates minimal (if any) weathering. Deposition at the lake bottom seems to have taken place in oxygen depleted layers. In this way, Camp dels Ninots is comparable to other remarkable maar sites such as Messel, the Eocene site situated in Germany

    Gravitational Lensing at Millimeter Wavelengths

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    With today's millimeter and submillimeter instruments observers use gravitational lensing mostly as a tool to boost the sensitivity when observing distant objects. This is evident through the dominance of gravitationally lensed objects among those detected in CO rotational lines at z>1. It is also evident in the use of lensing magnification by galaxy clusters in order to reach faint submm/mm continuum sources. There are, however, a few cases where millimeter lines have been directly involved in understanding lensing configurations. Future mm/submm instruments, such as the ALMA interferometer, will have both the sensitivity and the angular resolution to allow detailed observations of gravitational lenses. The almost constant sensitivity to dust emission over the redshift range z=1-10 means that the likelihood for strong lensing of dust continuum sources is much higher than for optically selected sources. A large number of new strong lenses are therefore likely to be discovered with ALMA, allowing a direct assessment of cosmological parameters through lens statistics. Combined with an angular resolution <0.1", ALMA will also be efficient for probing the gravitational potential of galaxy clusters, where we will be able to study both the sources and the lenses themselves, free of obscuration and extinction corrections, derive rotation curves for the lenses, their orientation and, thus, greatly constrain lens models.Comment: 69 pages, Review on quasar lensing. Part of a LNP Topical Volume on "Dark matter and gravitational lensing", eds. F. Courbin, D. Minniti. To be published by Springer-Verlag 2002. Paper with full resolution figures can be found at ftp://oden.oso.chalmers.se/pub/tommy/mmviews.ps.g

    ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

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    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a

    Paleoclimatic and paleoenvironmental context of the Early Pleistocene hominins from Dmanisi (Georgia, Lesser Caucasus) inferred from the herpetofaunal assemblage

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    10.1016/j.quascirev.2014.10.004Dmanisi is currently the oldest Early Palaeolithic site discovered out of Africa. It has produced over 40 hominin remains, including a set of very informative skulls, in direct association with faunal remains and numerous lithic artifacts. Given the relevance of this locality, every effort is being made to reconstruct the landscapes where these hominins once lived. Amphibian and reptile remains from Dmanisi are here described for the first time and used as paleoclimatic and paleoenvironmental proxies. They comprise at least six taxa: a green toad (. Bufo gr. Bufo viridis), the Greek tortoise (. Testudo graeca), a green lizard (. Lacerta gr. Lacerta viridis), a four-lined snake (. Elaphe gr. Elaphe quatuorlineata), an indeterminate colubrid and a water snake (. Natrix sp.). As these taxa are not extinct and their ecology can be directly studied, they can contribute to the reconstruction of the landscape and climate. The application of the Mutual Climatic Range method provides quantitative data indicating that during the hominin presence at Dmanisi climate was warm and dry, similar to the present-day Mediterranean climate. In comparison with today climate of Dmanisi, estimated mean annual temperature was 3.1°C higher, with a greater increase of temperature in summer (+7.1°C) than in winter (+4.7°C). The mean annual precipitation was slightly lower (-65mm) than the current level, with precipitation higher than current one during winter (+104mm) but strongly lower during the other seasons, suggesting a stronger contrast in the rainfall regime during the year. From a paleoenvironmental point of view, fossil amphibians and reptiles all suggest the predominance of arid environments, from steppe or semi-desert to open Mediterranean forest, with stony or rocky substrate and bus

    Multi-method approach using small vertebrate assemblages to reconstruct the Marine Isotope Stage 6 climate and environment of the Lazaret cave sequence (Maritime Alps, Nice, France)

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    Marine Isotope Stage 6 (MIS 6; ca. 185–135 ka) is the penultimate glacial stage and constitutes the end of the Middle Pleistocene. This glacial period is typified by generally cold and dry conditions in the western Mediterranean region. Despite the relatively large number of pollen and speleothem studies of MIS 6 in this region, the number of MIS 6 archaeological sites is low. Lazaret cave, situated at 26 m a.s.l. in the city of Nice in southern France, contains an archaeological sequence (layers CII inf. to CIII) dated to MIS 6. We present a multi-method approach using the small-vertebrate assemblages (mainly rodents and herpetofauna) from the entire sequence to characterize the climate and the environment of the site. The Mutual Ecogeographic Range, the Bioclimatic Model andthe Quantified Ecology methods, as well as the Taxonomic Habitat Index, Climatograms and the Simpson Diversity Index were used to reconstruct the palaeoenvironmental and palaeoclimatic conditions. The results suggest a generally cold climate with a relatively humid environment and a landscape dominated by deciduous temperate forests. The findings are consistent with the general trends reported from other proxies (large mammals, birds and marine gastropods) studied at Lazaret cave, other MIS 6 sites in the Mediterranean region with small vertebrate studies and the general trends shown by marine cores, terrestrial pollen sequences and speleothems from western Europe. Given the scarcity of data for MIS 6 archaeological sites, Lazaret cave constitutes an important site for our knowledge of the climate and the environment of this period

    Standardized precipitation index based on pearson type III distribution Índice padronizado de precipitação baseado na distribuição pearson tipo III

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    The initial step in calculating the Standardized Precipitation Index (SPI) is to determine a probability density function (pdf) that describes the precipitation series under analysis. Once this pdf is determined, the cumulative probability of an observed precipitation amount is computed. The inverse normal function is then applied to the cumulative probability. The result is the SPI. This article assessed the changes in SPI final values, when computed based on Gamma 2-parameters (Gam) and Pearson Type III (PE3) distributions (SPIGam and SPIPE3, respectively). Monthly rainfall series, available from five weather stations of the State of São Paulo, were chosen for this study. Considering quantitative and qualitative assessments of goodness-of-fit (evaluated at 1-, 3-, and 6-months precipitation totals), the PE3 distribution seems to be a better choice than the Gam distribution, in describing the long-term rainfall series of the State of São Paulo. In addition, it was observed that the number of SPI time series that could be seen as normally distributed was higher when this drought index was computed from the PE3 distribution. Thus, the use of the Pearson type III distribution within the calculation algorithm of the SPI is recommended in the State of São Paulo.<br>O cálculo do Índice Padronizado de Precipitação (IPP) inicia-se com a adoção de uma distribuição paramétrica (dp) utilizada para a estimativa das probabilidades de ocorrência associadas a uma série de precipitação pluvial. Após essa escolha, a probabilidade acumulada de ocorrência de um determinado valor de precipitação é calculada. O IPP é obtido após a aplicação da função normal inversa a essa probabilidade acumulada. O artigo avaliou as alterações nos valores finais do IPP, quando calculado com base nas distribuições Gama com dois parâmetros (Gam) e Pearson tipo III (PE3; IPPGam e IPPPE3, respectivamente). Utilizaram-se dados de precipitação pluvial de cinco localidades do Estado de São Paulo, nas escalas de 1, 3 e 6 meses. Aplicando testes de aderência, tanto qualitativos, quanto quantitativos, verificou-se que as probabilidades associadas às séries utilizadas foram melhores estimadas por meio da PE3. Foi também observado, que o número de séries temporais do IPP que podem ser consideradas normalmente distribuídas, foi maior quando este índice de seca foi calculado com base na PE3. Dessa forma, recomenda-se a adoção da PE3 no cálculo do IPP no Estado de São Paulo

    Terrasses de la Riera dels Canyars (Gavà, Barcelona): the landscape of Heinrich Stadial 4 north of the “Ebro frontier” and implications for modern human dispersal into Iberia

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    Terrasses de la Riera dels Canyars is an Upper Pleistocene fluvial deposit containing the remains of large mammals, principally accumulated in the framework of hyena denning in the area, as well as a few artifacts. Radiocarbon-dated tow39.6 ka cal BP, the time of Heinrich Stadial (HS) 4, this site enables us to reconstruct the environmental conditions then prevalent in the NE of the Iberian Peninsula. The concentration in a single locus of finds generated by different agents relates to a flash-flood event, the rapidity of which, combined with the absence of archaeological, ecological or paleontological incongruities in the composition of the assemblage, warrants an assumption of broad contemporaneity for its contents. The ecofactual evidence (fauna, pollen, charcoal, phytoliths) indicates a steppe-dominated environment for the coastal areas between the Pyrenees and the Ebro delta; the dominant elements are cold- and dry-adapted species but a Mediterranean component is present, implying a less rigorous climate than farther north in Europe. The artifacts are clearly Upper Paleolithic, and assignment to the modern human-associated Aurignacian technocomplex is supported by the radiocarbon dates and the typology of a bilaterally retouched blade. This evidence is consistent with the notion that anatomical modernity spread across Europe over open landscape niches. Available pollen data from deep sea cores indicate that, during some of the interstadials of Marine Isotope Stage (MIS) 3, a significant vegetation gradient existed at 40 N, broadly coincident with the “Ebro frontier:” temperate and warm temperate trees expanded significantly to the south, while steppe-tundra landscapes remained dominant to the north, a contrast best seen during Greenland Interstadial (GI) 8. Such an environmental boundary must have implied a durable barrier to diffusion and migration during interstadials. Under the cold and arid conditions of HS4, the site of Canyars shows that the Eurasian steppe-tundra extended as far south as the Llobregat delta; however, the environmental reconstructions available for the lower Ebro valley and adjacent mountains of the Iberian Range farther south suggest that they formed at this time a belt of semi-desert or steppe-desert landscapes, thus maintaining the boundary effect despite the climatic reversal. The persistence of such a boundary through HS4 and the interstadials that bracket it must have played a role in the delayed arrival of the Aurignacian (and modern humans) to southern and western Iberia, which continued to be settled by Middle Paleolithic Neanderthals well beyond 40 ka cal BP.info:eu-repo/semantics/publishedVersio
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