234 research outputs found

    Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous).

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    Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ? Palaeoscyllium sp., Prohaploblepharus riegrafi (Müller, 1989) gen. nov., ? Cretascyliorhinus sp., Scyliorhinidae inc. sedis 1, Scyliorhinidae inc. sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ? Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae, and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed

    Shark fossil diversity (Squalomorphii, Squatinomorphii, and Galeomorphii) from the Langhian of Brielas (Lower Tagus Basin, Portugal)

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    The fossiliferous marine Miocene sediments of the Lower Tagus Basin (Portugal) present a great diversity of Chondrichthyes forms. The current study focuses on the fossil sharks from the Langhian Vc unit of the Brielas section, located in the Setúbal Peninsula. A total of 384 isolated fossil teeth were analysed and ascribed to 17 species from the Orders Hexanchiformes, Squaliformes, Squatiniformes, Lamniformes, and Carcharhiniformes. Centrophorus granulosus and Iago angustidens are described for the first time in Portuguese sediments, whereas Pachyscyllium dachiardii and Rhizoprionodon ficheuri represent only their second reported occurrence. Galeorhinus goncalvesi was already known from the Portuguese uppermost Miocene (Alvalade Basin), but it is now recognized in older sediments. Furthermore, the new material seems to include the first reported occurrence of Hexanchus cf. agassizi in Miocene sediments. As a whole, these new findings support the previous palaeoenvironment characterization of a warm infralittoral setting gradually deepening to a circalittoral one, where seasonal upwelling phenomena could have occurred

    The centrosome and spindle as a ribonucleoprotein complex

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Chromosome Research 19 (2011): 367-376, doi:10.1007/s10577-011-9186-7.The presence of nucleic acids in centrosomes and the spindle have been proposed, observed, and reported since the 1950s. Why did the subject remain, perhaps even until today, such a controversial issue? The explanation is manifold, and includes legitimate concern over contamination from other cellular compartments in biochemical preparations. With a typically high background of cytoplasmic ribosomes, even microscopic images of stained intact cells could be difficult to interpret. Also, evidence for RNA and DNA in centrosomes accumulated for approximately 40 years but was interspersed with contradictory studies, primarily regarding the presence of DNA (reviewed in Johnson and Rosenbaum, 1991; Marshall and Rosenbaum, 2000). Perhaps less tangible but still a likely cause for lingering controversy is that the presence of nucleic acids in the spindle or centrosomes will require us to look differently at these structures from a functional, and more to the point, evolutionary standpoint.This work was supported by grants from the NIH (GM088503) and NSF (MCB0843092) to MCA

    O comércio internacional de peles silvestres na Amazônia brasileira no século XX

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    Durante o século XX, o comércio internacional de peles foi responsável pelo abate de milhões de mamíferos e répteis na Amazônia. Negociadas no regime de comércio fluvial e aviamento, as peles seguiam dos portos e seringais, localizados no interior, para as casas aviadoras e exportadoras de Manaus e Belém, de onde eram exportadas principalmente para os Estados Unidos, a Europa e o sul brasileiro. Neste artigo, analisamos documentos fiscais inéditos liberados pelo extinto império econômico do aviamento - a empresa J. G. Araujo -, bem como periódicos da Associação Comercial do Amazonas e os registros portuários da Manáos Harbour Ltd. O comércio internacional de peles silvestres intensificou-se imediatamente após a crise da borracha (1912) e atingiu seu auge entre 1935 e 1946, com o pico durante a Segunda Guerra Mundial. O segundo pico ocorreu na década de 1960, principal e ironicamente logo após a publicação da Lei de Proteção à Fauna (1967). Ao longo do período que antecedeu a aprovação da Convenção sobre o Comércio Internacional de Espécies Ameaçadas (CITES), em 1973-1975, não houve depreciação significativa no preço ou na demanda internacional por peles silvestres, sugerindo um esforço de caça constante e intenso por quase meio século

    Uma promenade nos trópicos: os barões do café sob as palmeiras-imperiais, entre o Rio de Janeiro e São Paulo

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    This paper proposes to discuss the transformation of urban landscapes in the Paraíba River Valley as members of the coffee elite emerged in this area and a specific landscape configuration was projected there based on the use of imperial palms (Roystonea oleracea). Chronologically speaking, the paper covers a period from 1808 to 1911; with regard to space, it focuses on the stretch between Rio de Janeiro and São Paulo, with a closer look at the case of the city of Lorena (SP), so as to encompass all the changes that took place in this region from the introduction to the decline of coffee growing as an economic activity. The urban changes during this period were accompanied by the advent and consolidation of landscapes typical of the society of coffee growers: streets lined with palm trees, a token of their close connections with the royal court, a display of their adherence to "Frenchified customs". Such configurations were used to characterize public areas and raise them to the same status as the new buildings that gradually replaced those built in colonial style. The paper is structured around three key moments, namely: the introduction of imperial palms in Rio de Janeiro and their association with the idea of nobility and rank, and consequently with neoclassical architecture, which was brought to the colony by the 1816 French Mission; the dissemination of the use of imperial palms as a landscaping resource typical of public spaces from the royal court to the capital of São Paulo, particularly by the coffee barons during the second period of monarchic rule; and, finally, the hypothesis that the use of imperial palms to embellish public areas in São Paulo may have been introduced by a Lorena citizen associated with the coffee elite, albeit later, when Brazil was already a republic.O presente trabalho propõe-se a discutir a transformação da paisagem urbana das cidades vale-paraibanas, a partir do estabelecimento de uma elite ligada à cultura do café nessa região e do surgimento de uma configuração paisagística específica, apoiada na utilização da palmeira-imperial (Roystonea oleracea). Seu recorte cronológico abrange o período entre 1808 e 1911, enquanto espacialmente seu foco direciona-se para o eixo Rio de Janeiro-São Paulo, com estudo mais aproximado do caso da cidade de Lorena, São Paulo, de modo a cobrir as transformações aí ocorridas desde a chegada do café até o esgotamento dessa cultura. Acompanhando as transformações urbanas do período, surgiram e consolidaram-se exemplos paisagísticos próprios da sociedade do café: ruas arborizadas com renques de palmeiras, a demonstrar a proximidade com a Corte, a sinalizar os novos "modos afrancesados". Utilizaram-se tais configurações com o propósito de qualificar os logradouros públicos, a fim de equipará-los aos novos edifícios que substituíam aqueles da tradição colonial. O texto desenvolve-se em três momentos principais: a introdução da palmeira-imperial no Rio de Janeiro, sua vinculação à idéia de nobreza e classe, e conseqüente aproximação com a arquitetura neoclássica trazida pela Missão Francesa de 1816; a difusão de sua utilização como recurso paisagístico qualificador dos espaços públicos desde a Corte até a capital paulista, principalmente pelo baronato do Segundo Império; e, finalmente, a possibilidade de sua introdução nos espaços públicos paulistanos ter sido viabilizada por um lorenense, vinculado à elite cafeeira, embora já sob a República

    Biogeography of Amazonian fishes: deconstructing river basins as biogeographic units

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    Obituary. Edward Charles Pelham-Clinton (1920-1988)

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    Volume: 3Start Page: 107End Page: 11
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