1,721,008 research outputs found
A large accumulation of avian eggs from the Late Cretaceous of Patagonia (Argentina) reveals a novel nesting strategy in Mesozoic birds
Get PDFWe report the first evidence for a nesting colony of Mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m2. These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods.Fil: Fernández, Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Garcia, Rodolfo Andres. Universidad Nacional de Rio Negro. Sede Alto Valle. Instituto de Investigaciones En Paleobiologia y Geologia; ArgentinaFil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; ArgentinaFil: Scolaro, Jose Alejandro. Universidad Nacional de la Patagonia "san Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Salvador, Rodrigo B.. Universidade de Sao Paulo. Instituto Quãmica de Sao Carlos; BrasilFil: Cotaro, Carlos N.. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Kaiser, Gary W.. Royal British Columbia Museum; CanadáFil: Dyke, Gareth J.. University Of Southampton; Reino Unid
Marcas de predación en un crocodiliforme peirosaurido del Cretácico Superior del Neuquén, Argentina
Get PDFEl hallazgo de marcas de mordeduras y lesiones por predación o comportamiento social agresivo intraespecífico en vertebrados fósiles es poco frecuente. En el registro fósil de arcosaurios suquianos tales evidencias son extraordinarias. Aquí se reporta un crocodiliforme peirosáurido del Cretácico Superior del Grupo Neuquén (norte de Patagonia, Argentina) con abundantes marcas de mordeduras y lesiones. Estas heridas están localizadas en todas las partes preservadas del espécimen, con una alta concentración de mordeduras, perforaciones y roturas en la región caudal. En el presente trabajo, se analizan las características de las lesiones, y también sus posibles causas y los aspectos tafonómicos relacionados. Los resultados muestran que las mordeduras fueron hechas por la acción de un predador y no por peleas intraespecíficas.Bite marks and injuries caused by intraspecific predation or aggressive social behavior are uncommon in fossil vertebrates, and in the fossil record of suchian archosaurs they are extremely unusual. A peirosaurid crocodyliform collected from the Upper Cretaceous beds of the Neuquén Group (northern Patagonia, Argentina) shows abundant bite marks and injuries. These injuries are spread across all the preserved parts of the specimen, with the highest concentration of bite marks, perforations and breakage in the caudal region. Characteristics of these injuries are analyzed, and their possible origin and related taphonomic aspects are assessed. Results indicate that the injuries were not produced by intraspecific fighting, but probably by the predating action of a theropod dinosaur.Fil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentin
Mammals from the Salicas formation (Late Miocene), La Rioja Province, northwestern Argentina : Paleobiogeography, age, and paleoenvironment
No full textFil: Brandoni, Diego. Laboratorio de Paleontología de Vertebrados. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Diamante; ArgentinaFil: Schmidt, Gabriela I.. Laboratorio de Paleontología de Vertebrados. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Diamante; ArgentinaFil: Candela, Adriana Magdalena. División Paleontología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Noriega, Jorge Ignacio. Laboratorio de Paleontología de Vertebrados. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Diamante; ArgentinaFil: Brunetto, Ernesto. Laboratorio de Paleontología de Vertebrados. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Diamante; ArgentinaFil: Fiorelli, Lucas E.. Departamento de Geociencias. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica; Anillaco; Argentin
Latrines collectives au Trias
Get PDFAu-delà des éléments fossilisés de leur corps (os, dents et plus exceptionnellement parties molles), les animaux du passé nous ont légué, enfouis dans les roches, d'autres témoignages précieux sur leur écologie et leur éthologie. C'est bien sûr le cas des traces de pas et autres pistes fossiles dont les études font l'objet d'un 'renouveau' depuis environ vingt-cinq ans. Elles livrent en effet des données inédites sur la locomotion et, plus largement, sur le comportement des espèces disparues. Plus amusant, c'est également le cas des coprolithes. Ces crottes fossiles sont connues comme telles depuis les débuts de la paléontologie: le terme savant -du grec kopros, excrément, et lithos, pierre- a été créé en 1829 par William Buckland, le 'père' du Megalosaurus, le premier dinosaure de la littérature scientifique.Fil: Corbara, Bruno . Centre National de la Recherche Scientifique; Francia. Universite Blaise Pascal; FranciaFil: Steyer, Jean-sébastien . Centre National de la Recherche Scientifique; Francia. Museum National D; FranciaFil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Quilmesaurus curriei Coria, 2001 (Dinosauria, Theropoda): Its taxonomic validity and phylogenetic relationships
Get PDFA comparative analysis of the Cretaceous theropod Quilmesaurus curriei from the Río Negro province, Patagonia, Argentina was performed in order to elucidate its phylogenetic relationships. Quilmesaurus was considered as basal Tetanurae by Coria (2001), however, Kellner & Campos (2002) suggested that this theropod could be a possible Abelisauria. In our analysis, we observed that the lack of fusion of the tibia with the astragalus- calcaneum is not an exclusive character for Ceratosauria; moreover, the mediodistal crest of femur is commonly well developed in Abelisauroidea. The great development of the distally expanded cnemial crest and the asymmetrical distal end of the tibia are characteristics of Abelisauridae. Finally, other characters like a distally directed process at the end of the cnemial crest and the asymmetry in the origin of the expansion of the malleolii in distal tibia are regarded as synapomorphies of Carnotaurinae. Therefore, Quilmesaurus curriei is considered to belong to Abelisauridae, and it is possibly a member of Carnotaurinae. On the basis of the available evidence, it is not possible to identify autapomorphic characters that allow validating Quilmesaurus curriei, and for this reason we consider it as a nomen vanum.Fil: Juárez Valieri, Rubén D.. Universidad Nacional del Comahue. Museo de Geología y Paleontología; ArgentinaFil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Cruz, Laura Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentin
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Novos restos de Notosuchus terrestris Woodward, 1896 (Crocodyliformes: Mesoeucrocodylia) do Cretáceo Superior de Neuquén, Patagônia, Argentina
Get PDFNew materials of Notosuchus terrestris are here described. They were found on Bajo de la Carpa Formation outcrops, near the Universidad Nacional del Comahue, Neuquén City. Descriptions were based on five specimens, one of them the only specimen of Notosuchus with postcranial remains articulated to the skull. As in Sphagesaurus, it presents triangular teeth in cross-section and oblique molariforms with worn facet surface. As in Mariliasuchus, it possesses procumbent mandibular incisiform teeth and, like in other notosuchians and basal crocodyliforms, it was able of proal mandibular movement. The centra of cervical vertebrae possess ventral keel as in Chimaerasuchus. Elongated cervical neural spines and suprapostzygapophyseal laminae in cervicodorsal vertebrae are observed. The scapular dorsal end is greatly enlarged, while the coracoid ventromedial process end is moderately developed. The dorsal surface of the ilium is lateromedially wide with a greatly expanded acetabular roof and a prominent anteromedial process in the femoral shaft. Based on diverse cranial and postcranial characters, we infer that Notosuchus possessed facial and perioral musculature well developed and an herbivore diet, confirming the suggestions of previous authors. Notosuchus represents, based on phylogenetic studies, the sister taxon of Mariliasuchus and the monophyly of Notosuchia is demonstrated. Paleobiogeographycally, the occurrence of Chimaerasuchus in China evidences the faunistic interchange between Gondwana and Central Asia during the Early Cretaceous.Novos materiais de Notosuchus terrestris são aqui descritos. Eles provêm de afloramentos da Formação Bajo de la Carpa, localizados próximos à Universidad Nacional del Comahue, na cidade de Neuquén. As descrições foram baseadas em cinco exemplares, um deles o único espécime de Notosuchus com restos pós-cranianos articulados ao crânio. Como em Sphagesaurus, N. terrestris apresenta dentes triangulares em seção cruzada e molariformes oblíquos com superfície da faceta com desgaste. Como em Mariliasuchus, a espécie possui dentes mandibulares incisiformes procumbentes e, como em outros notossúquios e crocodiliformes basais, era possível realizar o movimento antero-posterior mandibular. Os centros das vértebras cervicais possuem uma quilha ventral como em Chimaerasuchus. Espinhos neurais cervicais alongados e lâminas suprapószigapofiseais em vértebras cérvico-dorsais são observados. A extremidade escapular dorsal é amplamente alargada, enquanto a extremidade do processo ventro-medial do coracóide é pouco desenvolvida. A superfície dorsal do ilium é larga látero-medialmente com um teto acetabular amplamente expandido e processo ântero-medial proeminente na diáfise femoral. Baseado em diversos caracteres cranianos e pós-cranianos, infere-se que Notosuchus apresentava grande desenvolvimento da musculatura facial e perioral e tinha uma dieta herbívora, confirmando o que foi sugerido anteriormente por outros autores. Notosuchus representa, baseado em estudos filogenéticos, o táxon irmão de Mariliasuchus e a monofilia de Notosuchia é demonstrada. Paleobiogeograficamente, a ocorrência de Chimaerasuchus na China evidencia o intercâmbio faunístico entre o Gondwana e a Ásia Central durante o Cretáceo Inferior.Fil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina. Universidad Nacional del Comahue. Centro Paleontológico Lago Barreales; ArgentinaFil: Calvo, Jorge. Universidad Nacional del Comahue. Centro Paleontológico Lago Barreales; Argentin
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