80 research outputs found

    The axial skeleton of Bagualia alba (Dinosauria: Eusauropoda) from the Early Jurassic of Patagonia

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    Sauropod dinosaurs were the dominant large-bodied herbivores in many Mesozoic terrestrial ecosystems. Such predominance took place after a faunal replacement event linked to a global environmental change during the Early Jurassic (Pliensbachian-Toarcian), when the smaller basal sauropodomorphs were replaced by giant forms in the subclade Eusauropoda. Two main characteristics of this latter group are large body size (exceeding 10 tons) and a remarkably long neck. New data is presented on the axial anatomy of one of the earliest known eusauropods, Bagualia alba from the Toarcian levels of the Cañadón Asfalto Formation (Chubut Province, Argentina), which bear on the origins of these characteristics. Optimizing relevant axial characters on sauropodomorph phylogeny highlights important changes in cervical anatomy in the evolution of Sauropoda: a greater elongation of the neck due to both an increase in the vertebral count and the elongation of each cervical vertebra, and the appearance of pneumatic structures, first on the external surface (e.g., pleurocoels, laminae within the pleurocoels, accessory laminae of the neural arch) and subsequently invading the internal body of the vertebrae. These two changes have been considered essentials for body mass increase in Eusauropoda. The Toarcian age of Bagualia indicates that several important modifications in the axial skeleton and especially the neck occurred early in eusauropod evolution. These modifications are of ecomorphological importance and likely influenced the success of the eusauropods during the climatic changes surrounding the Pliensbachian-Toarcian crisis.Fil: Gomez, Kevin Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Carballido, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Pol, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; Argentin

    New information on a juvenile sauropod specimen from the Morrison Formation and the reassessment of its systematic position

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    Morphological changes in the ontogeny of sauropods are poorly known, making difficult to establish the systematic affinities of very young individuals. New information on an almost complete juvenile sauropod (SMA 0009) with an estimated total length of about 2m is here presented. The specimen was described as a diplodocid owing to the presence of some putative synapomorphies of this group. However, recent further preparation revealed the absence of diplodocid characters and the presence of macronarian derived characters. To test the affinities of this specimen, a phylogenetic analysis was conducted. The strict consensus tree recovers the specimen as a basal titanosauriform, in an unresolved relation with Brachiosaurus and Giraffatitan. Nevertheless, a brachiosaurid assignment is here suggested in base of the widely accepted monophyly of this group (only recovered when SMA 0009 is placed within this group). Although the existence of a new taxon cannot be completely ruled out, the combination of derived and plesiomorphic characters in the specimen suggests its assignment to Brachiosaurus. Sixteen extra steps are needed to place this specimen within Diplodocidae. The high cost to place this specimen within this group is owing to the fact that several diplodocid characters are absent in SMA 0009, such as the absence of divided centroprezygapophyseal lamina in cervical vertebrae, procoelous anterior caudal centra, composed lateral lamina in anterior caudal vertebrae, elongated middle caudal vertebrae, short cervical ribs and caudolateral projection of distal condyle of metatarsal I. Finally, the systematic position reveals few major ontogenetic transformations. These affect the pneumatic structures (e.g. change from simple pleurocoels in the cervical vertebrae to complex pleurocoels and the development of lateral excavations in the dorsal vertebrae) but also include unrecorded transformations of the neural spine (e.g. the development of the spinodiapophyseal lamina, the widening of the neural spines in the dorsal vertebrae) and allometric growth in some limb bones.Fil: Carballido, José Luis. Provincia del Chubut. Fundación Egidio Feruglio. Museo Paleontológico ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marpmann, Jean S.. Universitat Bonn; AlemaniaFil: Schwarz Wings, Daniela. Humboldt-Universität zu Berlin; AlemaniaFil: Pabst, Ben. No especifíca

    First evidence of ornithopod dinosaurs at the base of Huincul Formation (Cenomanian – Upper Turonian, Neuquén Basin, Argentina)

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    Se describe por primera vez la presencia de dinosaurios ornitópodos en la base de la Formación Huincul (Cenomaniense-Turoniense) de Agrio del Medio (Neuquén, Argentina). Se trata de una falange ungueal del pie bien conservada y de pequeño tamaño. Presenta una morfología general en forma de garra, similar a la de los ornitópodos basales que se han encontrado en el Cretácico Superior de Sudamérica, lo que le diferencia de las formas más derivadas de iguanodontios con ungueal en forma de casco. Este descubrimiento es una nueva evidencia que los pequeños ornitópodos basales se encontraban en la Cuenca Neuquina, al menos, desde el transito Cretácico Inferior-SuperiorWe describe for the first time the presence of ornithopod dinosaurs at the base of the Huincul Formation (Cenomanian-Turonian) of Agrio del Medio (Neuquén, Patagonia, Argentina). The specimen in question is a well-preserved and small phalanx toenail. It presents a general morphology in the form of a claw, similar to that of basal ornithopods that have been found in the Upper Cretaceous of South America. This differentiates it from the most derived iguanodontians, which have a hoof-shaped nail. This finding is new evidence than indicates that small basal ornithopods were in the Neuquén Basin at least since the transition of the Early-Late Cretaceou

    Modified laminar bone in Ampelosaurus atacis and other titanosaurs (Sauropoda): Implications for life history and physiology

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    Background: Long bone histology of the most derived Sauropoda, the Titanosauria suggests that titanosaurian long bone histology differs from the uniform bone histology of basal Sauropoda. Here we describe the long bone histology of the titanosaur Ampelosaurus atacis and compare it to that of basal neosauropods and other titanosaurs to clarify if a special titanosaur bone histology exists. Methodology/Principal Findings: Ampelosaurus retains the laminar vascular organization of basal Sauropoda, but throughout most of cortical growth, the scaffolding of the fibrolamellar bone, which usually is laid down as matrix of woven bone, is laid down as parallel-fibered or lamellar bone matrix instead. The remodeling process by secondary osteons is very extensive and overruns the periosteal bone deposition before skeletal maturity is reached. Thus, no EFS is identifiable. Compared to the atypical bone histology of Ampelosaurus, the large titanosaur Alamosaurus shows typical laminar fibrolamellar bone. The titanosaurs Phuwiangosaurus, Lirainosaurus, and Magyarosaurus, although differing in certain features, all show this same low amount or absence of woven bone from the scaffolding of the fibrolamellar bone, indicating a clear reduction in growth rate resulting in a higher bone tissue organization. To describe the peculiar primary cortical bone tissue of Phuwiangosaurus, Ampelosaurus, Lirainosaurus, and Magyarosaurus, we here introduce a new term, "modified laminar bone" (MLB). Conclusions/Significance: Importantly, MLB is as yet not known from extant animals. At least in Lirainosaurus and Magyarosaurus the reduction of growth rate indicated by MLB is coupled with a drastic body size reduction and maybe also a reduction in metabolic rate, interpreted as a result of dwarfing on the European islands during the Late Cretaceous. Phuwiangosaurus and Ampelosaurus both show a similar reduction in growth rate but not in body size, possibly indicating also a reduced metabolic rate. The large titanosaur Alamosaurus, on the other hand, retained the plesiomorphic bone histology of basal neosauropods.Fil: Klein, Nicole. Universitat Bonn; AlemaniaFil: Sander, P. Martin. Universitat Bonn; AlemaniaFil: Stein, koen. Universitat Bonn; AlemaniaFil: Loeuff, L. Jean.. Musée Des Dinosaures; FranciaFil: Carballido, José Luis. Provincia del Chubut. Fundación Egidio Feruglio. Museo Paleontológico ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Buffetaut, Éric. Centre National de la Recherche Scientifique; Franci

    G’3-stable semantics and inconsistency

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    We present an overview on how to perform non-monotonic reasoning based on paraconsistent logics. In particular, we show that one can define a logic programming semantics based on the paraconsistent logic G’3 which is called G’3-stable semantics. This semantics defines a frame for performing non-monotonic reasoning in domains which are pervaded with vagueness and inconsistencies. In fact, we show that, by considering also a possibilistic logic point of view, one can use this extended framework for defining a possibilistic logic programming approach able to deal with reasoning, which is at the same time non-monotonic and uncertain.Peer ReviewedPostprint (published version

    Paleoherpetology at the Museo Paleontologico Egidio Feruglio (Trelew, Chubut)

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    La herpetofauna extinta de la provincia de Chubut es una de las más diversas, temporal y espacialmente extensa, y mejor conocidas en Argentina y en Sudamérica. Estos fósiles ayudan a entender la evolución de la herpetofauna durante más de 180 millones de años, no solo en la región patagónica, sino que muchos de ellos tienen importancia a nivel mundial. Desde su establecimiento en 1990, el Museo Paleontológico Egidio Feruglio (MPEF) juega un rol clave en el descubrimiento, protección, estudio y exhibición de los importantes fósiles de la provincia. El estudio paleoherpetológico en el MPEF pasó por tres etapas diferentes: la Inicial, la Intermedia, y la Actual. Al presente, la colección de paleoherpetología del museo contiene aproximadamente 960 especímenes de anfibios y reptiles—incluyendo tortugas, lepidosaurios, plesiosaurios, cocodrilos, pterosaurios, dinosaurios, y aves—encontrados en formaciones sedimentarias que abarcan desde el Jurásico Temprano hasta el Mioceno tardío. Basados en estos materiales, al menos 32 nuevas especies fueron nominadas y más de 200 trabajos fueron publicados en menos de tres décadas.The extinct herpetofauna of the Chubut Province is one of the most diverse, temporally and spatially extensive, and well-known extinct faunas in Argentina and South America. These fossils help understanding the evolution of the herpetofauna during more than 180 million years, not only in the Patagonian region, but also in a worldwide scale due to the importance of some of them. Since its establishment in 1990, the Museo Paleontológico Egidio Feruglio (MPEF) plays a key role in the discovery, protection, study, and display of the important fossils of the Province. The paleoherpetological study at MPEF went through three different stages: the Initial, the Intermediate, and the Current stages. At present, the paleoherpetological collection contains approximately 960 specimens of amphibians and reptiles-including turtles, lepidosaurs, plesiosaurs, crocodiles, pterosaurs, dinosaurs, and birds-found in sedimentary formations that span from the Early Jurassic to the late Miocene. Based on this material, at least 32 new species were named, and more than 200 studies were published in less than three decades.Fil: Sterli, Juliana. Museo Paleontologico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pol, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Carballido, José Luis. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Puerta, Pablo. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Vlachos, Evangelos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; Argentin

    Nutrient supply does play a role on the structure of marine picophytoplankton communities

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    Conference communicationThe Margalef´s mandala (1978) is a simplified bottom-up control model that explains how mixing and nutrient concentration determine the composition of marine phytoplankton communities. Due to the difficulties of measuring turbulence in the field, previous attempts to verify this model have applied different proxies for nutrient supply, and very often used interchangeably the terms mixing and stratification. Moreover, because the mandala was conceived before the discovery of smaller phytoplankton groups (picoplankton <2 µm), it describes only the succession of vegetative phases of microplankton. In order to test the applicability of the classical mandala to picoplankton groups, we used a multidisciplinary approach including specifically designed field observations supported by remote sensing, database analyses, and modeling and laboratory chemostat experiments. Simultaneous estimates of nitrate diffusive fluxes, derived from microturbulence observations, and picoplankton abundance collected in more than 200 stations, spanning widely different hydrographic regimes, showed that the contribution of eukaryotes to picoautotrophic biomass increases with nutrient supply, whereas that of picocyanobacteria shows the opposite trend. These findings were supported by laboratory and modeling chemostat experiments that reproduced the competitive dynamics between picoeukaryote sand picocyanobacteria as a function of changing nutrient supply. Our results indicate that nutrient supply controls the distribution of picoplankton functional groups in the ocean, further supporting the model proposed by Margalef.Spanish Governmen

    60 Iconos Turísticos de Imbabura

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    Provincia de lagos y volcanes, biodiversa, artística, intercultural, multiétnica y poseedora de valores que la exponen como uno de los atractivos turístico más importantes del Ecuador. La Universidad Técnica del Norte mediante la publicación de este libro realiza un recorrido ilustrado de los 60 Iconos Turísticos de lmbabura, donde se investigan los ámbitos geográfico, histórico, cultural y social, lo que demuestra el potencial turístico de esta provincia y en donde los turistas podrán experimentar experiencias únicas. Imbabura cuenta con bondades turísticas de diferentes índoles. Este libro evidencia y difunde información técnica e ilustra con 181 magníficas fotografías la naturaleza, paisajes, flora, fauna, costumbres, cultura, historia, gastronomía, deportes, arte, arquitectura, artesanías y el patrimonio industrial, lo que representa una oportunidad para fortalecer el turismo y las implicaciones económicas y sociales que esto significa para la sociedad, lo que convierte a Imbabura en un patrimonio tangible e intangible del Ecuador y del mundo. La Universidad Técnica del Norte aporta en visibilizar y difundir los íconos turísticos más importantes de Imbabura, con base a una investigación exhaustiva en el marco de aportar al crecimiento y sostenibilidad del turismo y en procura del cumplimiento de la misión de la UTN. En este sentido, felicito a los profesores investigadores y fotógrafos autores de este libro, dirigidos por nuestro profesor de la FECYT, Albert Arnavat. Turismo diverso, cultural, rural, social y sostenible ponen a disposición los 60 íconos a los turistas nacionales y extranjeros, cuyos resultados servirán para convertir a la provincia de Imbabura en un icono turístico nacional e internacional

    Long-term follow-up of certolizumab pegol in uveitis due to immune-mediated inflammatory diseases : multicentre study of 80 patients

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    Objectives To evaluate effectiveness and safety of certolizumab pegol (CZP) in uveitis due to immune-mediated inflammatory diseases (IMID). Methods Multicentre study of CZP-treated patients with IMID uveitis refractory to conventional immunosuppressant. Effectiveness was assessed through the following ocular parameters: best-corrected visual acuity, anterior chamber cells, vitritis, macular thickness and retinal vasculitis. These variables were compared between the baseline, and first week, first, third, sixth months, first and second year. Results We studied 80 (33 men/47 women) patients (111 affected eyes) with a mean age of 41.6±11.7 years. The IMID included were: spondyloarthritis (n=43), Behçet's disease (n=10), psoriatic arthritis (n=8), Crohn's disease (n=4), sarcoidosis (n=2), juvenile idiopathic arthritis (n=1), reactive arthritis (n=1), rheumatoid arthritis (n=1), relapsing polychondritis (n=1), Conclusions CZP seems to be effective and safe in uveitis related to different IMID, even in patients refractory to previous biological drugs
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