121 research outputs found

    A reassessment of the origin and distribution of the subterranean genus Pseudolimnocythere Klie, 1938 (Ostracoda, Loxoconchidae), with description of two new species from Italy

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    Groundwater ecosystems host a rich and unique, but still largely unexplored and undescribed, biodiversity. Several lineages of ostracod crustaceans have subterranean representatives or are exclusively living in groundwaters. The stygobitic genus Pseudolimnocythere Klie, 1938 has a West Palearctic distribution, and includes few living and fossil species of marine origin. Through a comprehensive literature review and the description of the two new living species, Pseudolimnocythere abdita sp. nov. and Pseudolimnocythere sofiae sp. nov., from springs in the Northern Apennines, Italy, a morphological analysis was carried out with the aim of comparing the valve morphology of living and fossil species, and to discuss previous hypotheses about time and mode of colonization of inland waters. Pseudolimnocythere species show a low variability in valve morphology, with a remarkable stasis over geological times. The distribution of extant and fossil species is consistent with a scenario of multiple and independent events of colonization of continental habitats linked to sea level variations starting from Middle Miocene in the Paratethys and, later, in the Mediterranean. The most common colonization routes of inland waters have taken place through karst formations along ancient coastlines, although we cannot exclude some minor active migration through the hyporheic zone of streams. Available distribution data suggest a poor dispersal ability of Pseudolimnocythere species after they had colonized continental waters

    GEOLOGICAL EVOLUTION AND BIOCHRONOLOGICAL EVIDENCES OF THE MONTE RICCIO SECTION (TARQUINIA, CENTRAL ITALY)

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    The geological evolution of the area of M.te Riccio for the Plio-Pleistocene time span has been pointed out. The M.te Riccio area was probably an high during Gelasian-Santernian times. The stratigraphical sequence shows the passage from a coastal marine environment during Pliocene, to a coastal environment during Early Pleistocene (testified by evidences of shorelines) to continental conditions during the upper part of Pleistocene. The analysis of the mammal bones coming from a level overlying a marine formation ("Macco" auct.) allow us to ascribe the faunal association to the late Villafranchian (Tasso F.U.) referable to the beginning of the Pleistocene. It is the first signalation of an Early Pleistocene mammal fauna in the Northern Latium.&nbsp

    GEOLOGICAL EVOLUTION AND BIOCHRONOLOGICAL EVIDENCES OF THE MONTE RICCIO SECTION (TARQUINIA, CENTRAL ITALY)

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    The geological evolution of the area of M.te Riccio for the Plio-Pleistocene time span has been pointed out. The M.te Riccio area was probably an high during Gelasian-Santernian times. The stratigraphical sequence shows the passage from a coastal marine environment during Pliocene, to a coastal environment during Early Pleistocene (testified by evidences of shorelines) to continental conditions during the upper part of Pleistocene. The analysis of the mammal bones coming from a level overlying a marine formation ("Macco" auct.) allow us to ascribe the faunal association to the late Villafranchian (Tasso F.U.) referable to the beginning of the Pleistocene. It is the first signalation of an Early Pleistocene mammal fauna in the Northern Latium.&nbsp

    An introduction to the early Holocene eolian deposits of Grotta Romanelli, Apulia, Southern Italy

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    Due to its geographic position and geomorphological configuration, Grotta Romanelli acted as a sediment trap since at least MIS 5. The so-called 'terre brune' sequence is a deposit mainly of eolian origin bearing upper Palaeolithic artefacts and fossil re-mains of vertebrate fauna; it was deposited during the Glacial-Interglacial transition and the Holocene. Sedimentology and mineralogy of this deposit are investigated. The stratigraphic sequence provides a promising archive within which both human and climatic impacts can be studied

    Rediscovering Lutra lutra from Grotta Romanelli (southern Italy) in the framework of the puzzling evolutionary history of Eurasian otter

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    A river otter hemimandible has been rediscovered during the revision of the historical collections of G.A. Blanc from Grotta Romanelli, complementing the ongoing multidisciplinary research fieldwork on the site. The specimen, recovered from the level G (“terre rosse”; early Late Pleistocene or late Middle Pleistocene), is here assigned to Lutra lutra. Indeed, morphological and morphometric comparisons with other Quaternary Lutrinae fossils from Europe allow to exclude an attribution to the relatively widespread and older Lutra simplicidens, characterized by distinctive carnassial proportions. Differences with Cyrnaonyx antiqua, which possessed a more robust, shellfish-feeding dentition, support the view of a successful niche repartition between the two species during the late Middle to Late Pleistocene of Europe. The occurrence of Lutra lutra from the “terre rosse” of Grotta Romanelli suggests deep modifications of the landscapes due to the ecological adaptation of the taxon, and indicates that the Eurasian otter spread into Europe at the Middle–Late Pleistocene transition

    Palaeoenvironmental and palaeoclimatic evolution of the Shkodra Lake (Albania) during the last 4500 yr through ostracod proxies

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    Dedicatoria: "Dedicado al Exmo Sr. D. Mariano Roca de Togores, MarquĂ©s de Molins, Vizconde de Rocamora, Caballero profeso del hĂĄbito de Calatrava..."Coordenadas referidas al meridiano de Madrid (O 7°20'--E 9°45'/N 44°00'--N 35°00'). Red geogrĂĄfica de 1° en 1°Tabla de signos convencionales para indicar capitanĂ­as de 1a clase a 4a, cabeza de departamento, de tercios, provincias y distritos navales, escuelas de nĂĄutica, constructores navales, almadrabas y farosSe incluyen varias notas: "Pesca", "Pescado mas comĂșn del mar del Norte", "Nota sobre los faros", "Contraseñas de los buques mercantes por provincias", "Pescado mas comun del Guadiana al Estrecho", "Pescado mas comĂșn en el Mediterraneo", "Estado de la Marina"En el margen derecho consta una leyenda con los nombres de los marinos y viajeros cĂ©lebres agrupados por provincia

    Humans as the third evolutionary stage of biosphere engineering of rivers

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    We examine three fundamental changes in river systems induced by innovations of the biosphere, these being: (1) the evolution of oxygenic photosynthesis; (2) the development of vascular plants with root systems; and (3) the evolution of humans. The first two innovations provide context for the degree of human-induced river change. Early river systems of the Precambrian Archean Eon developed in an atmosphere with no free oxygen, and fluvial sediments accumulated ‘reduced detrital’ minerals. By 2.4 Ga the evolution of oxygenic photosynthesis produced an oxygenated atmosphere and ‘reduced detrital’ minerals mostly disappeared from rivers, affording a distinct mineralogical difference from subsequent fluvial deposits. Rivers of the Precambrian and early Phanerozoic were dominantly braided, but from 0.416 Ga, the evolution of vascular plants with roots bound floodplain sediments and fostered fine-grained meandering rivers. Early meandering river deposits show extensive animal activity including fish and arthropod tracks and burrows. Homo sapiens, appearing about 150 ka BP, has, in recent millennia, profoundly modified river systems, altering their mineralogical, morphological and sedimentary state. Changes in sediment fluxes caused by human ‘reverse engineering’ of the terrestrial biosphere include deforestation, irrigation and agriculture. Sediment retention has been encouraged by the construction of dams. Modern river systems are associated with extensive human trace fossils that show a developing complexity from ancient civilizations through to megacities. Changes induced by humans rank in scale with those caused by earlier biosphere innovations at 2.4 and 0.416 Ga, but would geologically soon revert to a “pre-human” state were humans to become extinct

    Definition of a new approach in ancient harbor geoarchaeology: geochemistry and ostracod analyses at Portus (Tiber delta, central Italy)

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    International audiencePortus constituted the harbour complex of imperial Rome from the 1st century AD onward. Located in a deltaic environment, the harbour was subject to influences of the Tyrrhenian marine environment and of the fluvial waters of the Tiber River. Such complex sedimentary processes registered also rapid environ-mental changes. Our research is based on the study of a sediment core (TR14) drilled in the access channel of the hexagonal basin of Trajan (Fig. 1). The goal of our study is the reconstruction the palaeo-environmental dynamics of the water column of the harbour according to a geochemical and an ostra-codological approach. The analysis of the ostracod assemblage has evidenced several palaeo-environmental phases. These phases could be identified through the autoeco-logical analysis of the 25 recognised taxa and their classification in four eco-logical groups (MAZZINI et al., 2011). The results obtained present a succession of four environments, defined by variations in salinity and oxygenation. From the bottom to a depth of 643 cm, the environment was a marine to brackish lagoon influenced by strong marine inputs as evidenced by the vic-ariance of Cyprideis torosa and Pontocythere turbida. P. turbida is a typical phy-tal ostracod often found together with Posidonia oceanica remains. From 600 to 454 cm the coastal marine environment becomes more stable. This could be linked to the establishment of the harbour activities and maintenance. The sta-bility of the environment is still evident in the subsequent group, from 435 to 305 cm, characterised by the dominance of C. torosa and the lack of any fresh-water influence. The increase in salinity could be related to evaporative effects on a closed body of water. From 300 cm the freshwater input becomes clear and constant although the influence of the close sea/brackish body of water is still noticeable. In the last metres a typical freshwater assemblage is represent-ed, dominated by truly freshwater taxa (Candona sp. and Pseudocandona marchica), evidence for the occurrence of a freshwater marsh. The geochemical results were analysed by Principal Components Analy-sis (PCA). The samples were assembled in several groups based on a Hierar-chical Ascendant Classification (cluster analysis). Through PCA analysis, the geochemical and ostracological results of the "functional" harbour unit (800-300 cm) were combined. The different elements recorded in the geochemical analysis are distributed according to the main ostracod assemblages (from fresh water to brackish water and sea water). These elements have been grouped according to the model proposed by SAGEMAN & LYONS (2003). An evolution of these deposits in three stages is proposed. While the fluvial envi-ronments were quite well oxygenated, the harbour environment was more characterised by an increasing anoxia of the water column as it was observed by ELMALEH et al. (2012) in the harbor of Tyre. In a second phase, the varia-tions in salinity distinguished the nature of the fluvial environments and the degree of openness to the sea of the harbour environment. The final phase is specific to a body of water completely isolated from fluviatile and marin

    An introduction to the early Holocene eolian deposits of Grotta Romanelli, Apulia, Southern Italy

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    Due to its geographic position and geomorphological configuration, Grotta Romanelli acted as a sediment trap since at least MIS 5. The so-called ‘terre brune’ sequence is a deposit mainly of eolian origin bearing upper Palaeolithic artefacts and fossil remains of vertebrate fauna; it was deposited during the Glacial-Interglacial transition and the Holocene. Sedimentology and mineralogy of this deposit are investigated. The stratigraphic sequence provides a promising archive within which both human and climatic impacts can be studied
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