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Academic literature on the topic 'Rio Essequibo'
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Journal articles on the topic "Rio Essequibo"
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Arbour, Jessica H., and Hernán López-Fernández. "Guianacara dacrya, a new species from the rio Branco and Essequibo River drainages of the Guiana Shield (Perciformes: Cichlidae)." Neotropical Ichthyology 9, no. 1 (March 2011): 87–96. http://dx.doi.org/10.1590/s1679-62252011000100006.
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A new species of Guianacara is described from tributaries of the Essequibo River and the rio Branco in Guyana and northern Brazil. Guianacara dacrya, new species, can be diagnosed from all congeners by the possession of a unique infraorbital stripe and by the shape of the lateral margin of the lower pharyngeal jaw tooth plate. Guianacara dacrya can be further distinguished from G. geayi, G. owroewefi, G. sphenozona and G. stergiosi by the possession of a thin midlateral bar, from G. cuyunii by the possession of dusky branchiostegal membranes and from G. oelemariensis by the possession of two supraneurals. This species differs from most congeners by the presence of white spots on the spiny portion of the dorsal fin, the placement of the midlateral spot, the presence of filaments on the dorsal, anal and in rare cases the caudal-fin and from at least the Venezuelan species by several morphometric variables. Guianacara dacrya is known from the Essequibo, Takutu and Ireng River basins of Guyana and possibly from the rio Uraricoera in the rio Branco basin in Brazil. A key to the species is provided.
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ARMBRUSTER, JONATHAN W., and LESLEY S. DE SOUZA. "Hypostomus macushi, a new species of the Hypostomus cochliodon group (Siluriformes: Loricariidae) from Guyana." Zootaxa 920, no. 1 (March 29, 2005): 1. http://dx.doi.org/10.11646/zootaxa.920.1.1.
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Hypostomus macushi is described as a new species of the H. cochliodon group based on the presence of a light background with widely separated black spots. The only members of the H. cochliodon group with similar coloration are H. cochliodon, H.ericae, H. ericius and H. paucipunctatus. Hypostomus macushi can be separated from H. cochliodon by lacking a longitudinal ridge on the pterotic-supracleithrum and a lack of longitudinal dark stripes; from H. ericius by lacking keels formed from sharp odontodes on the lateral plates; from H. ericae and H. paucipunctatus by lacking a buccal papilla; from H. ericae by having spots in the distal dorsal and caudal fins not combining (vs. spots combining to form wavy lines); and from H. paucipunctatus by having medium to large spots (vs. very small spots). Hypostomus macushi is found in tributaries of the Essequibo and Negro Rivers of Guyana. The range of H. taphorni is additionally expanded to cover much of the Essequibo River basin in Guyana and a single locality in the Takutu River drainage. Addition of H. macushi and H. sculpodon to the phylogeny of the Hypostomus cochliodon group collapsed most of the clades found in a previous analysis. Only the H. cochliodon group, the wood-specializing species, and H. ericius + H. oculeus are supported as clades.Hypostomus macushi é descrito como uma nova espécie do grupo H. cochliodon baseado no padrão de coloração do corpo claro com pontos esparços. Os únicos membros deste grupo com pigmentação similar são H. cochliodon, H.ericae, H. ericius e H. paucipunctatus. H. macushi difere de H. cochliodon pela ausência da crista do pterótico-supracleitro e pela ausência de listras largas; e difere de H. ericius pela presença de quilhas pouco desenvolvidas com odontóides arredondados; de H. ericae e H. paucipunctatus pela ausência de papila bucal; de H. ericae por apresentar máculas na porcão distal dorsal e nadadeira caudal organizados aleatóriamente (vs. máculas arranjadas formando linhas onduladas); e de H. paucipunctatus por porssuir máculas de tamanho médio a grande (vs. máculas diminutas). H. macushi é encontrado nos tributários dos Rios Essequibo e Negro, na Guiana. A distribuição de H. taphorni é expandida para a maior parte da bacia do Rio Essequibo e em uma localidade na drenagem do Rio Takutu. A adição de H. macushi e H. sculpodon na filogenia do grupo H. cochliodon colapsou a maioria dos clados encontrados em um estudo anterior.
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Bührnheim, Cristina M., and Luiz R. Malabarba. "Redescription of Odontostilbe pulchra (Gill, 1858) (Teleostei: Characidae: Cheirodontinae), and description of two new species from the río Orinoco basin." Neotropical Ichthyology 5, no. 1 (March 2007): 1–20. http://dx.doi.org/10.1590/s1679-62252007000100001.
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Odontostilbe pulchra, previously considered species inquirenda in Cheirodontinae and doubtfully assigned from the río Orinoco basin, is redescribed with the rediscovery of two syntypes. Originally described to the Island of Trinidad, O. pulchra is widespread in Venezuela, the río Orinoco basin, in smaller coastal drainages of northern South America, in the Lake Valencia system, and río Essequibo basin. A punctual occurrence in the upper rio Negro, near southernmost headwaters of the río Orinoco, extends its distribution to the Amazon basin. Additionally, two new species of Odontostilbe from the río Orinoco basin are described.
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ARMBRUSTER, JONATHAN W., and DONALD C. TAPHORN. "A new species of Pseudancistrus from the Rio Caroni Venezuela (Siluriformes: Loricariidae)." Zootaxa 1731, no. 1 (March 25, 2008): 33. http://dx.doi.org/10.11646/zootaxa.1731.1.3.
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Pseudancistrus reus is a new species from the Río Caroní (Río Orinoco drainage) of Venezuela known from two individuals. It differs from all other Pseudancistrus by having a color pattern consisting of alternating dark and light bars. In addition, it differs from all except P. genisetiger and P. papariae by having an incomplete mid-dorsal plate row and from P. genisetiger and P. papariae by having 18 contiguous mid-dorsal plates vs. 14 plates, a plateless break and then two more plates at the end of the caudal peduncle. The type locality of P. reus was submerged by the construction of the Caruachi dam, and is also the only known locality of the gymnotiform Sternarchorhynchus gnomus, making it imperative that the conservation status of these and other potential Caroní endemics be assessed. Pseudancistrus reus is the first species of Pseudancistrus sensu stricto from the Orinoco. Although the relationship of the species to other Pseudancistrus is unknown, P. reus may have gained access to the Orinoco either via stream capture between the Caroní and the Rio Uraricoera (Rio Branco – Rio Negro drainage) or via stream capture between the Caroní and either the Cuyuní or Mazaruni Rivers (Essequibo River drainage).key word: Siluriformes, Loricariidae, taxonomySe describe como especie nueva Pseudancistrus reus del río Caroní (cuenca del río Orinoco) en Venezuela, basada en dos ejemplares. Difiere de todas los demás Pseudancistrus en tener un patrón de pigmentación que consiste de barras claras alternando con oscuras. Además, difiere de todas los demás, menos P. genisetiger y P. papariae en tener la fila medio-dorsal de placas incompleta, y de P. genisetiger y P. papariae difiere en tener 18 placas medio-dorsales contiguas vs. 14 placas seguidas por una zona sin placas y luego dos placas más en el pedúnculo caudal). La localidad típica de P. reus fue sumergida por las aguas del embalse Caruachi. Ese sitio es también la localidad típica de Sternarchorhynchus gnomus, haciéndolo imprescindible evaluar el estado de conservación de estas dos especies más las otras endémicas del bajo Caroní. Pseudancistrus reus es la primera especies de Pseudancistrus sensu stricto de la cuenca del río Orinoco. Aunque desconocemos las relaciones con otras Pseudancistrus, P. reus puede haber ganado acceso al Caroní vía la captura de caños en las cabeceras del río Uraricoera-Branco-Negro o del río Cuyuní o Mazaruni, afluentes del río Essequibo.
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Souza, Jorge Manoel. "WAIWAI: UMA DESCRIÇÃO MÍNIMA À HISTÓRIA DO CONTATO." Boletim do Museu Integrado de Roraima (Online) 5, no. 01 (April 22, 2020): 01–12. http://dx.doi.org/10.24979/bolmirr.v5i01.730.
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Os Waiwai, índios de filiação karib, habitam atualmente aldeias localizadas ao norte do Brasil, nos Estados do Pará e Roraima, além do grupo localizado no rio Essequibo, na República Cooperativista da Guiana. A população atual dos Waiwai é superior a duas mil pessoas. Neste artigo, relato o processo de contato do grupo com a sociedade ocidental, em especial, a abor- dagem realizada por pesquisadores e estudiosos da questão indígena. O tema permite conhecer a origem da etnografia waiwai, a participação e a influência dos missionários entre esta sociedade, a movimentação dos grupos locais e, por fim, conseqüências advindas do contato.
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Sarmento-Soares, Luisa Maria, and José Luís Olivan Birindelli. "A new species of the catfish genus Centromochlus (Siluriformes: Auchenipteridae: Centromochlinae) from the upper rio Paraná basin, Brazil." Neotropical Ichthyology 13, no. 1 (March 2015): 77–86. http://dx.doi.org/10.1590/1982-0224-20140042.
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Centromochlus comprises twelve species, distributed in the main inland watersheds of South America, including the Orinoco, Essequibo, coastal rivers of Suriname, Amazon, upper Paraná and São Francisco basins. The new species is described from the upper rio Paraná based on material collected in 1965 during the construction of the UHE Ilha Solteira, São Paulo, Brazil. The new species is easily distinguished from all congeners due to absence of adipose fin, a condition otherwise restricted to Gelanoglanis nanonocticolus, among centromochlin catfishes. The new species comprises small catfishes (adults ranging from 35 to 39 mm SL), in which modified anal fin of males is devoid of denticulations or spines, and most posterior rays reduced in length. In addition, Tatia simplex Mees is transferred to Centromochlus and its generic reassignment discussed.
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CASATTI, LILIAN. "Taxonomy of the South American genus Pachypops Gill 1861 (Teleostei: Perciformes: Sciaenidae), with the description of a new species." Zootaxa 26, no. 1 (March 22, 2002): 1. http://dx.doi.org/10.11646/zootaxa.26.1.1.
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Pachypops is a South American freshwater sciaenid genus characterized by having two anal-fin spines, three mental barbels, an inferior mouth, a swimbladder with a pair of short appendages anteriorly and a pair of longer appendages projected posteriorly, and the haemal spine of the first caudal distinctly expanded. Three valid Pachypops species are recognized herein. Of the six nominal species previously assigned to Pachypops, two are herein recognized as valid (Perca fourcroi and Micropogon trifilis), two are assigned to other sciaenid genera (Pachypops adspersus and Pachypops cevegei) and two are considered junior synonyms (Corvina biloba and Pachypops camposi). A seventh nominal species, Pachyurus nattereri, formerly considered a valid species of Pachyurus, is determined to be a junior synonym of Pachypops fourcroi, and lectotype and paralectotypes are designated for it. Pachypops fourcroi occurs in the Orinoco, Amazonas, Essequibo, Corantijn, and Approuague River basins, and Pachypops trifilis in rivers of Guyana and middle and lower reaches of the Rio Amazonas basin. A third valid species, Pachypops pigmaeus n. sp., is herein described from tributaries of the Rio Amazonas, Brazil.
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LEHMANN A., PABLO, FLÁVIO C. T. LIMA, and ROBERTO E. REIS. "Parotocinclus yaka, a new species of armored catfish (Loricariidae: Hypoptopomatinae), from the Amazon basin in Brazil." Zootaxa 4521, no. 4 (November 15, 2018): 584. http://dx.doi.org/10.11646/zootaxa.4521.4.7.
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Parotocinclus yaka is described as a new species of hypoptopomatine cascudinho from tributaries of the Rio Tiquié, tributary to the Rio Uaupés, upper Rio Negro drainage, Amazon basin, Amazonas State, Brazil. The new species is distinguished from its congeners in northeastern and southeastern Brazil by having the cheek canal plate elongated posteriorly on the ventral surface of the head and in contact with the cleithrum. Parotocinclus yaka is diagnosed from the Parotocinclus species of the Amazon, Orinoco and Guianas watersheds by having a conspicuous dark spots smaller than the pupil diameter distributed dorsally and laterally on the head; it is also differentiated from P. polyochrus (Casiquiare, Venezuela), P. longirostris (Rio Amazonas, Brazil), and P. eppleyi (Río Orinoco) by the absence of a Y-shaped light mark dorsally on the head. In addition, the absence of premaxillary and dentary accessory teeth and the presence of a Y-shaped spot on the snout distinguish the new species from P. collinsae (Essequibo River, Guyana), P. halbothi (Rio Trombetas, Brazil and Marowijne River, Suriname) and P. variola (Río Amazonas, Colombia). Parotocinclus yaka also differs from P. amazonensis (lower Amazon basin), P. aripuanensis (lower Amazon basin), P. britskii (Guyana, Suriname, eastern Venezuela, and Amapá State, Brazil), and P. dani (Rio Tapajós basin), by having more numerous oral teeth. The new species described herein is part of the group of small cascudinhos usually associated with marginal or submerged vegetation and submerged logs, of moderate current and clear transparency, found in conserved habitats in streams of the Amazon, Orinoco and Guianas rivers.
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Lehmann A., Pablo, Lucas J. Schvambach, and Roberto E. Reis. "A new species of the armored catfish Parotocinclus (Loricariidae: Hypoptopomatinae), from the Amazon basin in Colombia." Neotropical Ichthyology 13, no. 1 (March 24, 2015): 47–52. http://dx.doi.org/10.1590/1982-0224-20140113.
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A new species of hypoptopomatine cascudinho is described from a creek tributary to the Amazon River in Leticia, Amazonas Departament, Colombia. The new species of Parotocinclus is distinguished from congeners from northeastern to southeastern Brazilian rivers in having the cheek canal plate elongated posteriorly on the ventral surface of head and contacting the cleithrum. It is diagnosed from P. collinsae (Essequibo River basin, Guiana) and P. halbothi (rio Trombetas basin, Brazil and Marowijne River, Suriname), by having a triangular patch of dark pigmentation on the anterior portion of the dorsal-fin membrane, by the absence of unicuspid accessory teeth on both the premaxilla and dentary, and by having a Y-shaped light mark on the snout. The new species of Parotocinclus is distinguished from all remaining congeners by having a pigmentation pattern consisting of conspicuous dark dots smaller than a pupil diameter, broadly distributed dorsally and ventrally.
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Vari, Richard P., Carl J. Ferraris Jr., and Mário C. C. de Pinna. "The Neotropical whale catfishes (Siluriformes: Cetopsidae: Cetopsinae), a revisionary study." Neotropical Ichthyology 3, no. 2 (June 2005): 127–238. http://dx.doi.org/10.1590/s1679-62252005000200001.
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The catfishes of the subfamily Cetopsinae of the Neotropical family Cetopsidae are revised. Four genera, Cetopsidium new genus, Cetopsis, Denticetopsis, and Paracetopsis Bleeker are recognized as valid. Bathycetopsis, Hemicetopsis, and Pseudocetopsis are considered synonyms of Cetopsis and Paracetopsis Eigenmann & Bean and Cetopsogiton synonyms of Paracetopsis. Thirty-seven species are recognized in the Cetopsinae. Cetopsidium includes six species: C. ferreirai, new species, rio Trombetas; C. minutum, Essequibo River; C. morenoi, central and western portions of río Orinoco; C. orientale, coastal rivers of Suriname and French Guiana, and tentatively rio Tocantins and rio Xingu; C. pemon, new species, río Caura, río Caroni, río Meta, and rio Branco; and C. roae, new species, Rupununi River. Cetopsis includes 21 species: C. amphiloxa, río San Juan, río Atrato, and río Patia, western Colombia, and rivers of northwestern Ecuador; C. arcana, new species, rio Tocantins; C. baudoensis, río Baudo; C. caiapo, new species, rio Tocantins; C. candiru, Amazon basin; C. fimbriata, new species, río Truando; C. coecutiens, rio Amazonas, rio Tocantins, and río Orinoco; C. gobioides, upper rio São Francisco, rio Paraná, río Uruguay, and rio Juquiá; C. jurubidae, río Jurubidá; C. montana, new species, western portions of Amazon basin; C. motatanensis, Lago Maracaibo basin; C. oliveirai, Amazon basin; C. orinoco, río Orinoco, río Aroa, and río Yaracuy; C. othonops, río Magdalena and río Sinú; C. parma, western Amazon basin; C. pearsoni, new species, upper portions of rio Madeira; C. plumbea, western portions of rio Amazonas; C. sandrae, new species, rio Tapajós; C. sarcodes, new species, rio Tocantins; C. starnesi, new species, northwestern río de La Plata and southern rio Madeira; and C. umbrosa, new species, western río Orinoco. Cetopsis chalmersi is a synonym of C. gobioides. Cetopsis macroteronema is a synonym of C. plumbea. Denticetopsis includes seven species: D. epa, new species, rio Tocantins; D. iwokrama, new species, Siparuni River; D. macilenta, Potaro River; D. praecox, río Baria; D. royeroi, upper río Negro; D. sauli, upper río Negro; and D. seducta, new species, western portions of rio Amazonas and río Orinoco. Paracetopsis consists of three species: P. atahualpa, new species, río Tumbes, northwestern Peru, and río Zarumilla, southwestern Ecuador; P. bleekeri, río Guayas and río Santa Rosa, south-western Ecuador; and P. esmeraldas, new species, rivers of northwestern Ecuador. Cetopsis ventralis and C. occidentalis are synonyms of Paracetopsis bleekeri. A neotype is designated for Paracetopsis bleekeri. Lectotypes are designated for Cetopsis candiru, Cetopsis chalmersi, and Cetopsis plumbeus.
Dissertations / Theses on the topic "Rio Essequibo"
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COUTINHO, Daniel Pires. "Revisão taxonômica do gênero Polycentrus Müller & Troschel, 1848 (Perciformes; Polycentridae) com a descrição de três novas espécies." Universidade Federal do Pará, 2010. http://repositorio.ufpa.br/jspui/handle/2011/4441.
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O gênero Polycentrus Müller & Troschel é revisado. Quatro espécies são reconhecidas P. schomburgkii redescrita e três espécies novas descritas. A diagnose do gênero é ampliada baseada em dados merísticos, morfológicos e do colorido. Polycentrus “Caxiuanã”, do baixo Amazonas, diferencia-se pela borda ventral do inter-opercular totalmente serreada vs. lisa ou parcialmente serreada nos congêneres, entre outros caracteres. Polycentrus n. sp. “Rio Negro”, do médio Rio Negro, pelo osso lacrimal liso vs. serreado nos congêneres mais a combinação de outros caracteres não exclusivos. Polycentrus n. sp. “Flechal”, da bacia do rio Araguari, diferencia-se por apresentar barra negra vertical no opérculo vs. máculas não formando barras nos congêneres, mais a combinação de outros caracteres não exclusivos. Uma chave dicotômica para espécies, bem como comentários sobres caracteres exclusivos e compartilhados são apresentados.
The genus Polycentrus Müller & Troschel is revised. Four species are recognized, P. schomburgkii is redescribed and three species are described as new. The genus diagnosis is enlarged based in meristic, morfology and colour pattern. Polycentrus n. sp. “Caxiuanã”, from Lowlands Amazon Bansin, is diagnosed by the totaly serrated interopercular edge vs. smooth or partialy serrated on the congeners. Polycentrus sp. n. “Rio Negro” from midle rio Negro, is diagnosed by the smooth lacrhymal bone vs. serrated in congeners plus a combination of non-exclusive characters. Polycentrus n. sp. “Flechal” is diagnosed by a dark opercular vertical bar vs. vertical opercular bar absent plus a combination of non-exclusive characters. A dichotomic key to species and remarks about exclusive characters is provided.