24 research outputs found

    Gareth Nelson: os desafios atuais e o futuro da biogeografia

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    The distribution of organisms has captured the attention of scientists for a long time. Great naturalists studied their groups of interest and described geographic patterns, evoking dispersion to explain their distribution. The development of phylogenetic systematics in the sixties represented a paradigm shift for biogeography, incorporating the concept of vicariance, process through which groups of organisms are isolated and differentiate, providing testable models in biogeography. In this context emerged Gareth Nelson, a North-American ichthyologist that contributed to the development of Cladistic Biogeography, providing its theoretical basis and proposing methodologies for its study. Herein, Nelson answers an interview regarding some of the main topics in modern biogeography such as its tendencies and future, interface with conservation, among other epistemological questions.A distribuição dos organismos tem chamado a atenção dos cientistas desde muito tempo. Grandes naturalistas preocuparam-se em estudar seus grupos de interesse e descrever padrões geográficos, evocando dispersão para explicar sua distribuição. O advento da sistemática filogenética na década de 60 representou uma mudança de paradigma na biogeografia incorporando o conceito de vicariância, processo pelo qual grupos de organismos são isolados e sofrem diferenciação, fornecendo assim modelos testáveis em biogeografia. Neste contexto apareceu Gareth Nelson, ictiólogo norte-americano que contribuiu para o desenvolvimento da Biogeografia Cladística, pautando suas bases teóricas e propondo metodologias para seu estudo. Neste artigo, Nelson responde uma entrevista tangenciando alguns dos principais assuntos da biogeografia moderna como suas tendências e futuro, interface com a conservação, e outras questões epistemológicas

    The quadrate-metapterygoid fenestra of otophysan fishes, its development and homology

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    We compare the ontogeny of the hyopalatine arch in representatives of the Otophysi to shed light on the homology of the so-called quadrate-metapterygoid fenestra, QMF. Described initially as a character of characiforms (tetras and allies), presence of a QMF has also been reported for cobitid loaches and a handful of cyprinids among cypriniforms, as well as for a few clupeoids. In characiforms the QMF is either already present as an opening in the palatoquadrate cartilage in the earliest developmental stages we studied, or it forms later in the cartilage by resorption of chondrocytes. Some characiforms may lack a QMF during all stages of development. In cobitids the so-called QMF develops after the bones have ossified and forms mainly by resorption of bone tissue of quadrate and metapterygoid. Previous reports of a QMF in cyprinids are erroneous and the opening in this area forms by spatial separation of the quadrate and metapterygoid from the symplectic and not by the formation of a fenestra in the palatoquadrate cartilage. We suggest referring to this type as a quadrate-metapterygoid gap, QMG. Presence of a QMF in the palatoquadrate cartilage is a putative synapomorphy of characiforms. Development of a QMF by bone resorption in the ossified palatoquadrate is a putative synapomorphy of Cobitidae. A QMG is variously present and developed to different degrees in opsariichthyine and danionine cyprinids. A QMF is also present in several clupeoids and deserves further study

    Molecular species delimitation and description of a new species of Phenacogaster (Teleostei, Characidae) from the southern Amazon basin

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    Phenacogaster is the most species-rich genus of the subfamily Characinae with 23 valid species broadly distributed in riverine systems of South America. Despite the taxonomic diversity of the genus, little has been advanced about its molecular diversity. A recent molecular phylogeny indicated the presence of undescribed species within Phenacogaster that is formally described here. We sampled 73 specimens of Phenacogaster and sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene in order to undertake species delimitation analyses and evaluate their intra- and interspecific genetic diversity. The results show the presence of 14 species, 13 of which are valid and one undescribed. The new species is known from the tributaries of the Xingu basin, the Rio das Mortes of the Araguaia basin, and the Rio Teles Pires of the Tapajós basin. It is distinguished by the incomplete lateral line, position of the humeral blotch near the pseudotympanum, and shape of the caudal-peduncle blotch. Meristic data and genetic differentiation relative to other Phenacogaster species represent strong evidence for the recognition of the new species and highlight the occurrence of an additional lineage of P. franciscoensis

    Para que servem os inventários de fauna?

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    Inventários de fauna acessam diretamente a diversidade de uma localidade, em um determinado espaço e tempo. Os dados primários gerados pelos inventários compõem uma das ferramentas mais importantes na tomada de decisões a respeito do manejo de áreas naturais. Entretanto, vários problemas têm sido observados em diversos níveis relacionados aos inventários de fauna no Brasil e vão desde a formação de recursos humanos até a ausência de padronização, de desenho experimental e de seleção de métodos inadequados. São apresentados estudos de caso com mamíferos, répteis, anfíbios e peixes, nos quais são discutidos problemas como variabilidade temporal e métodos para detecção de fauna terrestre, sugerindo que tanto os inventários quanto os programas de monitoramento devam se estender por prazos maiores e que os inventários devem incluir diferentes metodologias para que os seus objetivos sejam plenamente alcançados.Inventories of fauna directly access the diversity of a locality in a certain period of time. The primary data generated by these inventories comprise one of the most important steps in decisions making regarding the management of natural areas. However, several problems have been observed at different levels related to inventories of fauna in Brazil, and range from the training of humans to the lack of standardization of experimental design and selection of inappropriate methods. We present case studies of mammals, reptiles, amphibians and fishes, where they discussed issues such temporal variability and methods for detection of terrestrial fauna, suggesting that both inventories and monitoring programs should be extended for longer terms and that inventories should include different methodologies to ensure that their goals are fully achieved

    Religiosity and decreased risk of substance use disorders: is the effect mediated by social support or mental health status?

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    The negative association between religiosity (religious beliefs and church attendance) and the likelihood of substance use disorders is well established, but the mechanism(s) remain poorly understood. We investigated whether this association was mediated by social support or mental health status. We utilized cross-sectional data from the 2002 National Survey on Drug Use and Health (n = 36,370). We first used logistic regression to regress any alcohol use in the past year on sociodemographic and religiosity variables. Then, among individuals who drank in the past year, we regressed past year alcohol abuse/dependence on sociodemographic and religiosity variables. To investigate whether social support mediated the association between religiosity and alcohol use and alcohol abuse/dependence we repeated the above models, adding the social support variables. To the extent that these added predictors modified the magnitude of the effect of the religiosity variables, we interpreted social support as a possible mediator. We also formally tested for mediation using path analysis. We investigated the possible mediating role of mental health status analogously. Parallel sets of analyses were conducted for any drug use, and drug abuse/dependence among those using any drugs as the dependent variables. The addition of social support and mental health status variables to logistic regression models had little effect on the magnitude of the religiosity coefficients in any of the models. While some of the tests of mediation were significant in the path analyses, the results were not always in the expected direction, and the magnitude of the effects was small. The association between religiosity and decreased likelihood of a substance use disorder does not appear to be substantively mediated by either social support or mental health status

    Notes on the skeletal anatomy of Priocharax ariel Weitzman & Vari, 1987 with implications for its taxonomy (Teleostei: Characiformes)

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    Mattox, George M. T., Kubicek, Kole M., Britz, Ralf (2022): Notes on the skeletal anatomy of Priocharax ariel Weitzman & Vari, 1987 with implications for its taxonomy (Teleostei: Characiformes). Zootaxa 5138 (5): 597-599, DOI: https://doi.org/10.11646/zootaxa.5138.5.
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