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New euprimate postcrania from the early Eocene of Gujarat, India, and the strepsirrhineehaplorhine divergence
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The oldest primates of modern aspect (euprimates) appear abruptly on the Holarctic continents during a brief episode of global warming known as the Paleocene-Eocene Thermal Maximum, at the beginning of the Eocene (~56 Ma). When they first appear in the fossil record, they are already divided into two distinct clades, Adapoidea (basal members of Strepsirrhini, which includes extant lemurs, lorises, and bushbabies) and Omomyidae (basal Haplorhini, which comprises living tarsiers, monkeys, and apes). Both groups have recently been discovered in the early Eocene Cambay Shale Formation of Vastan lignite mine, Gujarat, India, where they are known mainly from teeth and jaws. The Vastan fossils are dated at ~54.5 Myr based on associated dinoflagellates and isotope stratigraphy. Here, we describe new, exquisitely preserved limb bones of these Indian primates that reveal more primitive postcranial characteristics than have been previously documented for either clade, and differences between them are so minor that in many cases we cannot be certain to which group they belong. Nevertheless, the small distinctions observed in some elements foreshadow postcranial traits that distinguish the groups by the middle Eocene, suggesting that the Vastan primatesdthough slightly younger than the oldest known euprimatesdmay represent the most primitive known remnants of the divergence between the two great primate clades.
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RBINS Staff Publications 2016
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First mammal species identified from the Upper Cretaceousof the Rusca Montana Basin (Transylvania, Romania)
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Multituberculate mammals are scarce in the Late Cretaceous of Europe, being recorded exclusively from the Maastrichtian terrestrial deposits of the Hateg and Transylvanian basins, in Romania. Moreover, they all belong to the endemic and primitive cimolodontan family Kogaionidae. Here, we report multituberculate teeth originating from the Maastrichtian fluviatile sediments of the Rusca Montana Basin (Occidental Carpathians, Poiana Rusca Mountains). This is the westernmost occurrence of these Cretaceous mammals in Romania. These teeth are assigned to Barbatodon oardaensis, the smallest Cretaceous kogaionid species. This study presents the first occurrence of this species outside the Metaliferi sedimentary area (southwestern Transylvania, Romania). The distribution of Romanian Maastrichtian kogaionids is also discussed.
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RBINS Staff Publications 2016
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Frasnian reef mounds in the Durbuy-Bomal area (eastern border of the Dinant Synclinorium, Belgium)
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RBINS Staff Publications 2022 OA
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The highly diversified rugose coral fauna from the Lower Givetian Meerbüsch quarry in the Eifel Hills (Germany).
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RBINS Staff Publications 2022 OA
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Late Devonian (Frasnian) phyllopod and phyllocarid crustaceanshields from Belgium reinterpreted as ammonoid anaptychi
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The taxonomic affinities of fossils from theFrasnian succession of Be lgium previously described asphyllopod and phyllocarid crustacean shields are discussed.The rediscovery of the holotype of Ellipsocaris dewalquei,the type species of the genus Ellipsocaris Woodward inDewalque, 1882, allows to end the discussion on the taxo-nomic assignation of the genus Ellipsocaris. It is removedfrom the phyllopod crustaceans as interpreted originally andconsidered here as an ammonoid anaptychus. Furthermore, itis considered to be a junior synonym of the genus SidetesGiebel, 1847. Similarly, Van Straelen’s (1933) lower to middleFrasnian record Spathiocaris chagrinensis Ruedemann, 1916,is also an ammonoid anaptychus. Although ammonoids canbe relatively frequent in some Frasnian horizons of Belgium,anaptychi remain particularly scarce and the attribution to thepresent material to peculiar ammonoid species is not possible.
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RBINS Staff Publications 2017
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A new Miocene baleen whale from Peru deciphers the dawn of cetotheriids
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RBINS Staff Publications 2017
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Latest Cretaceous storm-generated sea grass accumulations in the Maastrichtian type area, the Netherlands – preliminary observations
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RBINS Staff Publications 2019
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Publications
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Influence of Meteorological Variability on Primary Production Dynamics in the Ligurian Sea (NW Med Sea) with a 1D Hydrodynamic/Biological Model.
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In order to estimate the effects of the meteorological variability on the gross primary production in the Ligurian Sea (NW Mediterranean Sea), a coupling between a hydrodynamic model and a biological one is realized. The one-dimensional version of the GHER hydrodynamic model includes heat and momentum exchanges at the air–sea interface. It is coupled with a simple food-web model from the LEPM. A simulation performed with real meteorological data for the year 1985 reproduces reasonably the seasonal phytoplanktonic dynamics and the distribution between diatoms and flagellates. From this simulation, an annual gross primary production integrated over 200 m of 46.4 g C m−2 year−1 is computed which is representative of an oligotrophic environment. In order to estimate the relative effect on the gross primary production of the meteorological variability on the one hand and of the initial conditions on the other hand, several runs have been performed for the year 1985 with different conditions of light, wind intensity and nitrate initial quantity. The first simulations are performed with daily and monthly mean solar radiation and wind intensity. An averaging of wind intensity yields a decrease in the gross primary production and leads to unrealistic phytoplankton dynamics. It seems then necessary to take into account the 3-hourly variability of the wind intensity in order to simulate the phytoplankton dynamics with relatively good accuracy. On the other hand, an averaging of the solar radiation leads to an increase in the gross primary production. The following simulations are performed with an increase (decrease) in the solar radiation, the wind intensity or the nitrate initial quantity which are representative of the variability observed in a 5-year set of meteorological and hydrobiological data (1984–1988). An increase in the solar radiation is found to reduce the gross primary production, while an increase in the initial nitrate quantity or the wind intensity leads to a higher gross primary production, and the reverse. In the case of variations of the solar radiation (±2%), the simulations give an annual gross primary production integrated over 200 m included between 44.8 and 46.7 g C m−2 year−1, representing a variability of 4%. With the variations of the surface wind intensity (±10%), the runs carry to an annual gross primary production integrated over 200 m from 34.1 to 59.1 g C m−2 year−1, representing a variability of 54%. The variations of the initial nitrate concentration (±50%) lead to an annual gross primary production integrated over 200 m between 20.7 and 69.8 g C m−2 year−1 which represents a variability of 108%. An analysis of the relationship between the total gross primary production and the annual mean depth of the mixed layer has shown that the deeper the mixed layer is, the higher is the total annual gross primary production.
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Study of the oxygen budget of the Black Sea waters using a 3D coupled hydrodynamical-biogeochemical model.
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The ventilation of the Black Sea waters by physical and biogeochemical processes is investigated using the Geohydrodynamics and Environment Research (GHER) laboratory 3D coupled hydrodynamical–biogeochemical model. In particular, the penetration at depth of the winter mixing, the generation of unstable motions by frontal instabilities, the exchanges between the north-western shelf and the open sea along the shelf break, the primary production distribution, the generation of detritus and the resulting consumption of oxygen for their recycling are studied. The GHER 3D hydrodynamic model is used to simulate the Black Sea's general circulation and the associated synoptic and mesoscale structures. This model is coupled with a simple ecosystem model defined by a nitrogen cycle which is described by seven state variables: nitrate, ammonium, dissolved oxygen, phytoplankton, zooplankton, pelagic and benthic detritus. The model simulates the space–time variations of the biogeochemical state variables. In particular, the spatial variability of the phytoplankton biomass annual cycle, imparted by the horizontal and vertical variations of the physical and chemical properties of the water column, is clearly illustrated. For instance, on the north-western shelf, the seasonal variability of the circulation and in particular, the reversal of the surface current at the end of spring, has a strong influence on the transport of the rich nutrient Danube waters and, thus, on the repartition of the primary production. Furthermore, the results illustrate the seasonal and vertical variations of the dissolved oxygen concentration resulting (a) from its atmospheric and photosynthetic productions in the surface layer, (b) from its loss to the atmosphere in spring and summer and (c) from its consumption associated with the detritus decomposition, the ammonium oxidation during the nitrification process, as well as the oxidation of hydrogen sulfide. The simulated sea surface, phytoplankton fields are compared with satellite estimates of chlorophyll-a fields. Comparisons are made with seasonal mean pictures and snapshot images, illustrating the mesoscale motions of the main coastal current. In the central Black Sea and the Danube delta area, comparisons with available field data are also made. As a general rule, all these comparisons show a quite good qualitative agreement. In particular, at the surface, the simulated phytoplankton space–time distribution is in a good qualitative agreement with satellite observations. However, on a quantitative point of view, the model underestimates the bloom intensity especially in the Danube discharge area.
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