412 research outputs found

    Anatomy and phylogenetic relationships of a new catfish species from northeastern Argentina with comments on the phylogenetic relationships of the genus Rhamdella Eigenmann and Eigenmann 1888 (Siluriformes, Heptapteridae)

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    Rhamdella cainguae, a new species of the family Heptapteridae is described from the Arroyo Cuña-Pirú, a tributary of the Río Paraná, in the subtropical forest of Misiones, northeastern Argentina. The presence of a large differentiated ovoid area on the supraorbital laterosensory canal along the frontal-sphenotic boundary, delimited by the slender dorsal walls of the bones, and with no foramen for a laterosensory branch, is an autapomorphy for R. cainguae. A detailed description of the skeleton and laterosensory system of R. cainguae is provided. The genus Rhamdella is rediagnosed on the basis of three autapomorphies: a very large opening in the frontal for the exit of the s6 (epiphyseal) branch of the supraorbital laterosensory canal (reversed in R. rusbyi), a large optic foramen, and a dark stripe along the lateral surface of the body (reversed in R. rusbyi). Rhamdella is considered to be the sister group of a large heptapterid clade composed of the Nemuroglanis sub-clade plus the genera Brachyglanis, Gladioglanis, Leptorhamdia, and Myoglanis. Rhamdella is herein restricted to five valid species: R. aymarae, R. cainguae, R. eriarcha, R. longiuscula, and R. rusbyi. A sister group relationship between R. aymarae and R. rusbyi is supported by three synapomorphies. Rhamdella cainguae shares 12 apomorphic features with R. eriarcha and R. longiuscula.Facultad de Ciencias Naturales y Muse

    The earliest iconographic record of Gobioides broussonnetii La Cepède, 1800 (Gobiiformes: Gobiidae): the species identity of the “Caramuru” paintings of Dutch Brazil (1624-1654)

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    During the Mauritian period of Dutch Brazil (1637‑1644), a great deal of information about the biota of northeastern Brazil was obtained, consisting of both written records and paintings. Among them is an eel-like fish, depicted in two paintings labeled “Caramurû” and “Caramuru”, whose taxonomic identity is controversial. One of them, attributed to Albert Eckhout, is part of the Theatrum Rerum Naturalium Brasiliae collection, stored at the Jagiellonian University Library, in Poland. This painting was possibly a model for the second “Caramuru”, of unknown authorship, which is deposited at the Archive of the Russian Academy of Sciences. These paintings are doubtfully identified as the snake eel Echiophis intertinctus (Ophichthidae, Anguilliformes), a proposal likely induced by the vulgar name “caramuru”, which is applied to muraenids and ophichthids in Brazil. After careful examination of these two paintings regarding the anatomical details depicted, we concluded that the fish corresponds, with great certainty, to Gobioides broussonnetii (Gobiidae, Gobiiformes), popularly known as “aimoré” and “tajasica”. Furthermore, we suggest the possibility that the written counterpart of these paintings is the description associated with the woodcut of the fish labeled as “Tajasica” in the Historia Naturalis Brasiliae (Marggraf in de Laet, 1648). The confusion probably stems from mismatches between Georg Marggraf’s descriptions and the images of organisms produced at the time, perhaps before the return of Johan Maurits van Nassau-Siegen’s entourage to Europe. In an attempt to support our conclusions about the identity of that fish, as well as for historical purposes, we also discuss the vernacular names applied to G. broussonnetii and the authorship of the notes made on those paintings

    Anatomy and phylogenetic relationships of a new catfish species from northeastern Argentina with comments on the phylogenetic relationships of the genus Rhamdella Eigenmann and Eigenmann 1888 (Siluriformes, Heptapteridae)

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    Rhamdella cainguae, a new species of the family Heptapteridae is described from the Arroyo Cuña-Pirú, a tributary of the Río Paraná, in the subtropical forest of Misiones, northeastern Argentina. The presence of a large differentiated ovoid area on the supraorbital laterosensory canal along the frontal-sphenotic boundary, delimited by the slender dorsal walls of the bones, and with no foramen for a laterosensory branch, is an autapomorphy for R. cainguae. A detailed description of the skeleton and laterosensory system of R. cainguae is provided. The genus Rhamdella is rediagnosed on the basis of three autapomorphies: a very large opening in the frontal for the exit of the s6 (epiphyseal) branch of the supraorbital laterosensory canal (reversed in R. rusbyi), a large optic foramen, and a dark stripe along the lateral surface of the body (reversed in R. rusbyi). Rhamdella is considered to be the sister group of a large heptapterid clade composed of the Nemuroglanis sub-clade plus the genera Brachyglanis, Gladioglanis, Leptorhamdia, and Myoglanis. Rhamdella is herein restricted to five valid species: R. aymarae, R. cainguae, R. eriarcha, R. longiuscula, and R. rusbyi. A sister group relationship between R. aymarae and R. rusbyi is supported by three synapomorphies. Rhamdella cainguae shares 12 apomorphic features with R. eriarcha and R. longiuscula.Facultad de Ciencias Naturales y Muse

    Trichomycterus maracaya, a new catfish from the upper rio Paraná, southeastern Brazil (Siluriformes: Trichomycteridae), with notes on the T. brasiliensis species-complex

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    Trichomycterus maracaya, a new species of Trichomycteridae, is described from a streamlet in the upper rio Paraná, Poços de Caldas, State of Minas Gerais, southeastern Brazil. The following putative autapomorphies distinguishes T. maracaya from congeneric species: 1) row of lateral blotches not forming a stripe at any phase during ontogeny; 2) superficial layer of pigmentation of juveniles and large (presumably adults) specimens consisting solely of scattered chromatophores. Furthermore, the new species is characterized by a combination of yellow ground color in life and mottled pattern formed by small to medium-sized, brown, irregularly-coalescent, well-defined deeper-lying blotches, and more superficial dots on the body. Trichomycterus maracaya is assigned to the T. brasiliensis species-complex (which includes T. brasiliensis, T. iheringi, T. mimonha, T. potschi, T. vermiculatus, and several undescribed species apparently endemic to the main river basins draining the Brazilian Shield) based on the presence of: 1) blotches in four longitudinal rows of deeper-lying pigmentation on the trunk large, horizontally-elongated, and well-defined; 2) pectoral fin with I+5-6 rays; 3) separation between the anterior and posterior cranial fontanels by the primordial epiphyseal cartilaginous bar being present only in larger specimens; and 4) pelvic-fin bases very close to each other, sometimes in contact.Trichomycterus maracaya, uma espécie nova de Trichomycteridae, é descrita de exemplares obtidos num riacho do alto rio Paraná, Poços de Caldas, Estado de Minas Gerais, sudeste do Brasil. As seguintes supostas autapomorfias distinguem T. maracaya de outras espécies do gênero: 1) fileira de manchas laterais que não se fundem em listra em nenhuma fase da ontogenia; 2) camada superficial de pigmentação de juvenis e exemplares maiores (supostamente adultos) consistindo somente de cromatóforos dispersos. Além disso, a nova espécie é caracterizada pela combinação de coloração de fundo amarela em vida e padrão mosqueado, formado por manchas castanhas pequenas a médias bem definidas e aglutinadas irregularmente, situadas em camada mais profunda do tegumento, além de pontos mais superficiais espalhados pelo corpo. Trichomycterus maracaya é aqui designada ao complexo de espécies T. brasiliensis (que inclui T. brasiliensis, T. iheringi, T. mimonha, T. potschi e T. vermiculatus, além de várias espécies não descritas, aparentemente endêmicas às bacias dos rios principais que drenam o Escudo Brasileiro), com base em: 1) manchas horizontalmente alongadas, grandes e bem definidas, situadas mais profundamente no tegumento e dispostas em quatro fileiras longitudinais no corpo; 2) nadadeira peitoral com I+5-6 raios; 3) separação entre as fontanelas cranianas anterior e posterior, por barra cartilaginosa primordial da epífise, apenas nos exemplares maiores; e 4) bases das nadadeiras pélvicas muito próximas uma da outra, por vezes em contato.617

    Phylogenetic relationships of Chanidae (Teleostei: Gonorynchiformes) as impacted by Dastilbe moraesi, from the Sanfranciscana basin, Early Cretaceous of Brazil

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    Fossil gonorynchiform fishes range from the Lower Cretaceous to the early Miocene, and are represented by a few dozen living species. The order is currently divided into two major clades: Gonorynchoidei, which includes the families Gonorynchidae and Kneriidae, and Chanoidei, encompassing a single family, Chanidae, with a single recent species, the Indo-Pacific Chanos chanos, and several fossil taxa. Chanidae includes some poorly known taxa, such as Dastilbe moraesi, described from the Aptian (Lower Cretaceous) of the Areado Formation, Sanfranciscana basin, Brazil. This species is currently considered to be a junior synonym of the type species of its genus, Dastilbe crandalli, from Santana Formation, Aptian, northeastern Brazil. The analysis of abundant D. moraesi specimens revealed several new morphological features, many of which had previously been misinterpreted. Dastilbe moraesi was incorporated into a gonorynchiform character matrix as revised and modified for the Chanidae. We obtained a single most parsimonious tree in which D. moraesi is distinct and phylogenetically apart from D. crandalli. According our analysis, D. moraesi forms a sister pair with Chanos, a clade which is closely related to Tharrhias, all composing the tribe ChaniniGonorynchiformes fósseis ocorrem desde do Cretáceo inferior ao Mioceno inferior, e são representados por alguns representantes viventes. A ordem está dividida atualmente em dois clados principais: Gonorynchoidei, que inclui as famílias Gonorynchidae e Kneriidae, e Chanoidei, compreendendo uma única família, Chanidae, com uma única espécie vivente, Chanos chanos, do Indo-Pacífico, além de vários representantes fósseis. Chanidae inclui alguns táxons problemáticos, tais como Dastilbe moraesi, descrito do Aptiano (Cretáceo Inferior) da Formação Areado, bacia Sanfranciscana, Brasil. Esta espécie é atualmente considerada um sinônimo júnior da espécie-tipo de seu gênero, Dastilbe crandalli, da Formação Santana, Aptiano do nordeste do Brasil. A análise de abundante material de D. moraesi revelou várias novas características anatômicas, muitas das quais haviam sido previamente mal interpretadas. Dastilbe moraesi foi incorporado em uma matriz revisada de caracteres da família Chanidae. Nós obtivemos uma única árvore mais parcimoniosa na qual D. moraesi é distinto e filogeneticamente distante de D. crandalli. De acordo com nossa análise, D. moraesi é o grupo-irmão de Chanos, um clado intimamente relacionado a Tharrhias, com todos compondo a tribo ChaniniThis study was supported by CNPq (process # 401818/2010-1) and project CGL2013-42643P, Ministerio de Ciencia e Innovación de Españ

    Effects of food-borne nanomaterials on gastrointestinal tissues and microbiota

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    Ingestion of engineered nanomaterials is inevitable due to their addition to food and prevalence in food packaging and domestic products such as toothpaste and sun cream. In the absence of robust dosimetry and particokinetic data, it is currently challenging to accurately assess the potential toxicity of food-borne nanomaterials. Herein, we review current understanding of gastrointestinal uptake mechanisms, consider some data on the potential for toxicity of the most commonly encountered classes of food-borne nanomaterials (including TiO2 , SiO2 , ZnO, and Ag nanoparticles), and discuss the potential impact of the luminal environment on nanoparticle properties and toxicity. Much of our current understanding of gastrointestinal nanotoxicology is derived from increasingly sophisticated epithelial models that augment in vivo studies. In addition to considering the direct effects of food-borne nanomaterials on gastrointestinal tissues, including the potential role of chronic nanoparticle exposure in development of inflammatory diseases, we also discuss the potential for food-borne nanomaterials to disturb the normal balance of microbiota within the gastrointestinal tract. The latter possibility warrants close attention given the increasing awareness of the critical role of microbiota in human health and the known impact of some food-borne nanomaterials on bacterial viability. For further resources related to this article, please visit the WIREs website.</p

    Identification of Melatonin-Regulated Genes in the Ovine Pituitary Pars Tuberalis, a Target Site for Seasonal Hormone Control

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    The pars tuberalis (PT) of the pituitary gland expresses a high density of melatonin (MEL) receptors and is believed to regulate seasonal physiology by decoding changes in nocturnal melatonin secretion. Circadian clock genes are known to be expressed in the PT in response to the decline (Per1) and onset (Cry1) of MEL secretion, but to date little is known of other molecular changes in this key MEL target site. To identify transcriptional pathways that may be involved in the diurnal and photoperiod-transduction mechanism, we performed a whole genome transcriptome analysis using PT RNA isolated from sheep culled at three time points over the 24-h cycle under either long or short photoperiods. Our results reveal 153 transcripts where expression differs between photoperiods at the light-dark transition and 54 transcripts where expression level was more globally altered by photoperiod (all time points combined). Cry1 induction at night was associated with up-regulation of genes coding for NeuroD1 (neurogenic differentiation factor 1), Pbef / Nampt (nicotinamide phosphoribosyltransferase) , Hif1α (hypoxia-inducible factor-1α), and Kcnq5 (K channel) and down-regulation of Rorβ, a key clock gene regulator. Using in situ hybridization, we confirmed day-night differences in expression for Pbef / Nampt, NeuroD1, and Rorβ in the PT. Treatment of sheep with MEL increased PT expression for Cry1, Pbef / Nampt, NeuroD1, and Hif1α, but not Kcnq5. Our data thus reveal a cluster of Cry1-associated genes that are acutely responsive to MEL and novel transcriptional pathways involved in MEL action in the PT

    Developing a Collaborative Strategy to Manage and Preserve Cultural Heritage During the Libyan Conflict. The Case of the Gebel Nafusa

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    The paper discusses the potential of a collaborative scheme for the development of a protocol for recording and managing the cultural heritage in Libya. The critical political situation in the country urges the development of cultural heritage management policies in order to protect it more thoroughly and consistently. Moving on from the numerous international initiatives and projects dealing with a mostly “remote” approach to the issue, the project here presented to engages with staff members of the Department of Antiquities (DoA) in the development of a joint strategy for the application of remote sensing and geographical information systems (GIS) to the preservation and monitoring of Libyan cultural heritage. A series of training courses resulted in an initial development of new ways of recording and analysing field data for a better awareness of the full range of threats that the archaeology of the country is subject to. Focussing on the case of the Jebel Nafusa, the training involved the assessment of site visibility on satellite imagery, the analysis of high-resolution satellite datasets for archaeological mapping, the creation of a GIS spatial database of field data, and the mapping of risks and threats to archaeology from remote sensing data. This led to the creation of of a risk map showing the areas that are affected by a number of threats, thus giving the DoA a tool to prioritise future fieldwork to keep the assessment of site damage up to date. Only a collaborative approach can lead to a sustainable strategy for the protection of the invaluable cultural heritage of Libya

    Baryon masses from lattice QCD: Beyond the perturbative chiral regime

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    Consideration of the analytic properties of pion-induced baryon self-energies leads to new functional forms for the extrapolation of light baryon masses. These functional forms reproduce the leading non-analytic behavior of chiral perturbation theory, the correct non-analytic behavior at the NπN \pi threshold and the appropriate heavy-quark limit. They involve only three unknown parameters, which may be obtained by fitting to lattice data. Recent dynamical fermion results from CP-PACS and UKQCD are extrapolated using these new functional forms. We also use these functions to probe the limit of applicability of chiral perturbation theory to the extrapolation of lattice QCD results.Derek B. Leinweber, Anthony W. Thomas, Kazuo Tsushima, and Stewart V. Wrigh

    Ancestral TSH mechanism signals summer in a photoperiodic mammal

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    SummaryIn mammals, day-length-sensitive (photoperiodic) seasonal breeding cycles depend on the pineal hormone melatonin, which modulates secretion of reproductive hormones by the anterior pituitary gland [1]. It is thought that melatonin acts in the hypothalamus to control reproduction through the release of neurosecretory signals into the pituitary portal blood supply, where they act on pituitary endocrine cells [2]. Contrastingly, we show here that during the reproductive response of Soay sheep exposed to summer day lengths, the reverse applies: Melatonin acts directly on anterior-pituitary cells, and these then relay the photoperiodic message back into the hypothalamus to control neuroendocrine output. The switch to long days causes melatonin-responsive cells in the pars tuberalis (PT) of the anterior pituitary to increase production of thyrotrophin (TSH). This acts locally on TSH-receptor-expressing cells in the adjacent mediobasal hypothalamus, leading to increased expression of type II thyroid hormone deiodinase (DIO2). DIO2 initiates the summer response by increasing hypothalamic tri-iodothyronine (T3) levels. These data and recent findings in quail [3] indicate that the TSH-expressing cells of the PT play an ancestral role in seasonal reproductive control in vertebrates. In mammals this provides the missing link between the pineal melatonin signal and thyroid-dependent seasonal biology
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