15 research outputs found

    A new Eliomys from the Upper Miocene of Spain and its implications for the phylogeny of genus

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    In this paper, we describe a previously unknown species of the glirid Eliomys from the Late Miocene and Early Pliocene Cabriel, Alcoy and Granada basins of southeastern Spain. Eliomys yevesi sp. nov. is characterized by its relative small size, narrow lingual wall and common presence of two centrolophs in the upper molars, and well-developed centrolophids in the lower molars. The new species is the probable ancestor of E. intermedius, which in turn represents the ancestor of the extant E. quercinus. According to its morphologic and biometric features, the origin of E. yevesi sp. nov. is likely to be found in some population of E. truci from the Late Miocene. Based on these affinities, we propose the lineage E. truci–E. yevesi sp. nov.–E. intermedius–E. quercinus, in which there is a trend towards the development of centrolophs, as well as the reduction of accessory crests

    Anwendungsbezogene Forschung und Entwicklung im Rahmen des Technologietransfers

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    TIB Hannover: RO 7159(4) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

    Late Turolian micromammals from Rambla de Chimeneas-3: considerations on the oldest continental faunas from the Guadix Basin (Southern Spain)

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    The fauna from Rambla de Chimeneas-3 (RCH-3), a new uppermost Miocene micromammal site from the Guadix Basin, is described. This level has yielded remains of Paraethomys meini, Occitanomys alcalai, Stephanomys cf. dubari, Cricetinae indet., Erinaceidae indet., and Soricidae indet. This faunal assemblage can be assigned to the upper Turolian (MN13). The section of Rambla de Chimeneas is situated in the lower part of the oldest exclusively continental stratigraphic unit distinguished in the filling of the Guadix Basin. Other rodent faunas from this unit were previously assigned to the middle Turolian (MN12). In this paper we reconsider the age of the oldest mammal localities from the Guadix Basin, concluding that none of them can be clearly assigned to MN12. Therefore, there is no evidence of the continentalization of the basin before the late Turolian

    The late Miocene continentalization of the Guadix Basin (southern Spain) reconsidered: a comment on Hüsing et al. (2010)

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    Hüsing et al. (2010: Palaeogeography Palaeoclimatology Palaeoecology 291, 167–179) made an approximation to the age of the closure of the Betic Seaway through the Guadix Basin during the late Miocene, on the basis of integrated paleontological (foraminifera and micromammals) and magnetostratigraphic data from the marine-continental section of La Lancha. They provide very interesting information that contributes to understand the chronology of the marine to continental transition in the basin, but we would like to comment some inaccuracies in the interpretation of the age of the oldest continental levels of the studied section. Moreover, we discuss several recently described late Miocene continental faunas from the Guadix Basin, such as Negratín-1 and Rambla de Chimeneas-3, which were not considered by Hüsing et al. for their interpretations. Finally, we review the age of the site of Salinas, originally assigned to MN12 and discussed by Hüsing et al., but which had already been reconsidered by other authors who concluded that the existence of middle Turolian mammal faunas in this basin cannot be demonstrated

    Filling the gap: first evidence of early Tortonian continental deposits in southern Iberia

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    The oldest Miocene continental fauna in the Guadix-Baza depression from southern Spain is described in this paper. The small mammals remains from Cortijo de la Piedra fossil localities have a latest Vallesian (early Tortonian) age, and provide evidence of late Vallesian continental environments, which were unknown until now in southern Iberia. The age of the reported assemblage is previous to the establishment of the Guadix-Baza Basin sensu stricto. It represents the oldest Miocene continental mammalian fauna found thus far in southern Iberia, and proves the presence of connections with the foreland. The small mammals from Cortijo de la Piedra display a similar size and morphology as those recorded on the mainland, showing no particular traits that might be interpreted as insular features. These continental faunas suggest that the North-Betic Foreland Basin was at least partially closed at the end of the early Tortonian

    Late Pleistocene–Holocene environmental conditions in Lanzarote (Canary Islands) inferred from calcitic and aragonitic land snail shells and bird bones

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    Aragonitic and calcitic land snails from carbonate-rich paleosols in northwestern Lanzarote (Canary Islands) were analyzed for 13C/12C and 18O/16O ratios to deduce the Pleistocene–Holocene transition in the westernmost Sahara zone. Modern, mid-late Holocene (~ 2.1–5.5 cal ka BP) and late Pleistocene (~ 23.3–24.0 cal ka BP) aragonitic shells exhibited respective values of − 9.5 ± 1.6‰, − 7.7 ± 1.5‰, and − 2.3 ± 2.8‰ for δ13C; and + 0.3 ± 0.3‰, + 0.1 ± 0.7‰, and + 2.5 ± 0.4‰ for δ18O. Holocene and Pleistocene calcitic shells of the endemic slug Cryptella canariensis showed respective values of − 0.7 ± 2.6‰ and − 8.5 ± 2.5‰ for δ13C; and + 0.8 ± 1.5 and + 3.6 ± 0.4‰ for δ18O. Both aragonitic and calcitic shells showed equivalent temporal isotopic trends. Higher δ13C values during ~ 23.3–24.0 cal ka BP suggest higher abundance of C4 and/or CAM plants, likely associated with drier conditions and/or lower atmospheric CO2 concentration. Maximum shell δ18O values during ~ 23.3–24.0 cal ka BP opposes minimal values of Greenland ice cores and probably reflect the combined effects of (1) higher rain δ18O values linked to higher glacial seawater δ18O values and/or larger snail activity during summer seasons; (2) relative humidity values similar or slightly lower than at present; (3) higher evaporation rates; and (4) cooler temperatures. Bone remains of the extinct Dune Shearwater Puffinus holeae were only recovered from the Holocene bed. Collagen δ13C and δ15N values (− 13.5 ± 0.2‰[PDB] and + 13.7 ± 1.0‰[air], respectively) match with the signature of a low trophic level Macaronesian seabird that fed upon local fish. Bone carbonate δ13C (− 7.4 ± 1.0‰[PDB]) and phosphate δ18O (+ 18.2 ± 0.4‰[SMOW]) values exhibited pristine signals denoting their potential value in future paleoenvironmental studies in the region. The age of P. holeae (~ 2.1–2.7 cal ka BP) supports that the aboriginal population possibly caused its extinction. In contrast, the extinction of the endemic helicid Theba sp. (~ 23.3–24.0 cal ka BP) was likely caused by environmental change

    Environmental control on the biogeographical distribution of Desmanella (Soricomorpha, Mammalia) in the Miocene of the Iberian Peninsula

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    This paper reports the first record of Desmanella (Mammalia, Soricomorpha) from the Granada Basin in southern Iberian Peninsula, which represents its south-westernmost occurrence in all Eurasia. It is a controversial taxon whose systematic assignment has been discussed for a long time. This genus belongs to the family Talpidae, a group of insectivores that include extant moles, shrew moles and desmans. Desmanella was very abundant in the late Miocene and early Pliocene of Eurasia, including several basins of northern Iberian Peninsula, but it has not been found until now in southern Iberia. Previous studies have shown that the faunal record and the climatic conditions during the Neogene in the Granada Basin were different from other areas of the Iberian Peninsula. The particular distribution of Desmanella supports the hypothesis that specific climatic features (wetter than neighbouring areas) prevailed in the Granada Basin during the late Turolian (late Miocene)

    Holocene environmental change in southern Spain deduced from the isotopic record of a high-elevation wetland in Sierra Nevada

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    Small lakes and wetlands from high elevation within the Sierra Nevada Range (southern Spain) preserve a complete post-glacial Holocene record. Isotopic, TOC and C/N analyses, carried out on a sediment core, show various stages in the evolution of the Borreguiles de la Virgen, which today constitute a small bog at about 2,950 m above sea level. Glacial erosion generated a cirque depression, which became a small lake during the first phase of infilling (from 8,200 to 5,100 cal yr BP), as suggested by sedimentary evidence, including an atomic C/N ratio generally below 20, low TOC values and the highest δ13C and δ15N values of the record. These results imply significant algal productivity, which is confirmed by the microscopic algal remains. Drier conditions became established progressively in this area from 5,100 to 3,700 cal yr BP. Subsequently, the lake evolved into a bog as shown by geochemical evidence (C/N ratios above 20, high TOC content and low δ13C values). Unstable conditions prevailed from 3,600 to 700 cal yr BP; an extremely low sedimentation rate and scarcity of data from this period do not allow us to make a coherent interpretation. Fluctuating conditions were recorded during the last ~700 cal yr BP, with wetter conditions prevailing during the first part of the interval (with C/N rate below 20) up to 350 years ago. In general, a gradual trend toward more arid conditions occurred since ~6,900 cal yr BP, with a further increase in aridity since ~5,100 cal yr BP. This evidence is consistent with other contemporaneous peri-Mediterranean records

    Review of paleo-humidity parameters in fossil rodents (Mammalia): Isotopic vs. tooth morphology approach

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    Paleoecology of fossil rodents is frequently inferred from the dental pattern of the teeth, attributing the habitat conditions of extant rodents to fossil species with similar dental pattern. This technique is common practice and has been in use for several decades. A relatively new technique is based on the carbon and oxygen isotope composition of the incisor enamel of fossil rodents to reconstruct paleoenvironmental scenarios. We combine these two methods, studying material from two Early Miocene Spanish sections, one in the Mediterranean coastal area and one in Northcentral inland Spain. Comparison of the humidity values obtained by means of these two proxies reveals discrepancies. Therefore, we analyzed the habitat preferences, especially humidity, of extant rodents and found that dental pattern is not very reliable to reconstruct the humidity preferences of fossil rodents and this kind of interpretation has to be taken with caution. We conclude that the isotopic composition of enamel of fossil teeth is a more reliable proxy in the studied sections

    Vegetation, fire, climate and human disturbance history in the southwestern Mediterranean area during the late Holocene

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    Detailed pollen, charcoal, isotope and magnetic susceptibility data from an alpine lake sediment core from Sierra Nevada, southern Spain record changes in vegetation, fire history and lake sedimentation since ca. 4100 cal yr BP. The proxies studied record an arid period from ca. 3800 to 3100 cal yr BP characterized by more xerophytic vegetation and lower lake levels. A humid period is recorded between ca. 3100 and 1850 cal yr BP, which occurred in two steps: (1) an increase in evergreen Quercus between 3100 and 2500 cal yr BP, indicating milder conditions than previously and (2) an increase in deciduous Quercus and higher lake levels, between ca. 2500 and 1850 cal yr BP, indicating a further increase in humidity and reduction in seasonal contrast. Humid maxima occurred during the Roman Humid Period, previously identified in other studies in the Mediterranean region. Intensified fire activity at this time could be related to an increase in fuel load and/or in human disturbance. An arid period subsequently occurred between 1850 and 650 cal yr BP, though a decrease in Quercus and an increase in xerophytes. The alternation of persistent North Atlantic Oscillation modes probably played an important role in controlling these humid–arid cycles
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