Sistemática do gênero Ageneiosus La Cépède (Siluriformes Auchenipteridae)

The catfish genus Ageneiosus is revised and a new hypothesis of phylogenetic relationships inter- and intra-generic is proposed. The taxonomic revision was based on the examination of available type specimens and analysis to the original descriptions. Taxonomic accuracy of the species was tested by morphometric, meristic and qualitative analyses of internal and external anatomy. Valid species were considered in the study of phylogenetic relationships. The phylogenetic analysis included 239 characters coded for 41 terminal taxa. Formerly with 12 species, the genus Ageneiosus comprises currently 19 species recognized herein as valid, some of which are widely distributed across large rivers in South America. Ageneiosus pardalis is the only trans-Andean species in the genus. Ageneiosus marmoratus is a junior synonym of Ageneiosus inermis. Ageneiosus dentatus and Ageneiosus rondoni are valid species and their names are removed from the synonymy of Ageneiosus ucayalensis and Ageneiosus brevis, respectively. Six new species are recognized. The parsimony analysis resulted in a single most parsimonious tree with 631 steps, consistency index 0.52 and retention index 0.85. The monophyly of Ageneiosus is corroborated and its diagnosis includes 10 synapomorphic characters unique between the Auchenipteridae. The genus is composed of two main clades: (1) clade comprising the majority of the species with large and not ossified swimbladder and (2) clade comprising Ageneiosus pardalis and the species with reduced and ossified swimbladder in large individuals. The ressurrection of Tympanopleura is proposed to accommodate the species of the first clade. According to the hypothesis presented here, the clade Ageneiosus-Tympanopleura is the sister-group of Tetranematichthys and the clade composed of these genera is the sister-group of (Entomocorus (Auchenipterus (Epapterus, Pseudepapterus))). A key for all nineteen valid species of Ageneiosus species is provided.O gênero Ageneiosus é revisado e uma hipótese das relações filogenéticas inter- e intra-genérica é proposta. A revisão taxonômica contou com o exame do material tipo disponível e consulta às descrições originais. A validade das espécies foi testada por meio de comparações estatísticas das medidas e contagens e análises qualitativas dos caracteres de anatomia interna e externa. Espécies conclusivamente válidas foram consideradas no estudo de relações filogenéticas. A análise filogenética incluiu 239 caracteres codificados para 41 táxons terminais. Ageneiosus, até então reconhecido numa composição com 12 espécies, é composto por 19 espécies válidas, algumas das quais amplamente distribuídas por grandes rios da América do Sul. Ageneiosus pardalis é a única espécie trans-Andina no gênero. Ageneiosus marmoratus é um sinônimo júnior de Ageneiosus inermis. Ageneiosus dentatus e Ageneiosus rondoni são espécies válidas e seus nomes são retirados da sinonímia de Ageneiosus ucayalensis e Ageneiosus brevis, respectivamente. Seis espécies novas foram reconhecidas. A análise de parcimônia resultou em uma única árvore mais parcimoniosa com 631 passos, índice de consistência 0,52 e índice de retenção 0,85. A monofilia de Ageneiosus é corroborada e sua diagnose inclui 10 caracteres sinapomórficos exclusivos entre os Auchenipteridae. O gênero é composto por dois grandes clados: (1) composto pela maioria das espécies com bexiga natatória grande e não ossificada e (2) composto por Ageneiosus pardalis e pelas espécies com bexiga natatória reduzida e ossificada em indivíduos grandes. É proposta a revalidação do gênero Tympanopleura para o primeiro clado. O clado Ageneiosus- Tympanopleura é grupo-irmão de Tetranematichthys e o clado composto por esses gêneros é grupo-irmão de (Entomocorus, (Auchenipterus, (Epapterus, Pseudepapterus))). É apresentada uma chave para identificação de todas as dezenove espécies válidas de Ageneiosus

Ageneiosus uranophthalmus, a new species of auchenipterid catfish (Osteichthyes: Siluriformes) from river channels of the central Amazon basin, Brazil

Ageneiosus uranophthalmus is described from river channels of the central Amazon basin, Brazil. The new species is widely distributed in the Amazon and is distinguished from its congeners by the V-shape snout and eye laterally placed and dorsally oriented, more visible in dorsal view than in ventral view. Ageneiosus uranophthalmus shows a range of variation on color pattern when compared with its congeners. This and other differences are described and discussed herein. © 2010 Sociedade Brasileira de Ictiologia

Pimelodus heraldoi Azpelicueta, 2001, a junior synonym of Pimelodus microstoma Steindachner, 1877 (Siluriformes: Pimelodidae)

The examination of the holotype and 61 of the 64 paratypes of Pimelodus heraldoi, syntypes of P. microstoma and additional specimens from the upper rio Paraná showed that the former species is a junior synonym of the latter. Both species were originally described from the rio Mogi-Guaçu, upper rio Paraná. © 2010 Sociedade Brasileira de Ictiologia

Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species

The Neotropical catfish genus Tympanopleura, previously synonymized within Ageneiosus, is revalidated and included species are reviewed. Six species are recognized, two of which are described as new. Tympanopleura is distinguished from Ageneiosus by having an enlarged gas bladder not strongly encapsulated in bone; a prominent pseudotympanum consisting of an area on the side of the body devoid of epaxial musculature where the gas bladder contacts the internal coelomic wall; short, blunt head without greatly elongated jaws; and smaller adult body size. Species of Tympanopleura are distinguished from each other on the basis of unique meristic, morphometric, and pigmentation differences. Ageneiosus melanopogon and Tympanopleura nigricollis are junior synonyms of Tympanopleura atronasus. Tympanopleura alta is a junior synonym of Tympanopleura brevis. A lectotype is designated for T. brevis. Ageneiosus madeirensis is a junior synonym of Tympanopleura rondoni. Tympanopleura atronasus, T. brevis, T. longipinna, and T. rondoni are relatively widespread in the middle and upper Amazon River basin. Tympanopleura cryptica is described from relatively few specimens collected in the upper portion of the Amazon River basin in Peru and the middle portion of that basin in Brazil. Tympanopleura piperata is distributed in the upper and middle Amazon River basin, as well as in the Essequibo River drainage of Guyana. © 2015 Sociedade Brasileira de Ictiologia

Three new Pimelodus species (Siluriformes: Pimelodidae) from the rio Tocantins drainage, Brazil

Three new species of Siluriformes from the rio Tocantins drainage of Brazil are placed in the genus Pimelodus, P. stewarti, P. joannis, and P. halisodous. Pimelodus halisodous differs from the sympatric P. joannis and P. stewarti by the number of premaxillary tooth rows (13-16 vs. 5-9). Pimelodus joannis differs from P. stewarti by the presence of two dark blotches on the base of the caudal fin. The three new species differ from all other species of Pimelodus by the possession of a uniform gray coloration along flanks; the relatively short distance between the posterior nostril and the anterior orbital border; a short maxillary barbel, that only slightly surpasses the caudal-fin base. Copyright © 2008 Sociedade Brasileira de Ictiologia

Karyotypic variation in the long-whiskered catfish Pimelodus blochii Valenciennes, 1840 (Siluriformes, Pimelodidae) from the lower Tapajós, Amazonas and Trombetas Rivers

The genus Pimelodus LaCépède, 1803 comprises 35 formally recognized species distributed along the major neotropical river basins. Despite conservatism in diploid number with 2n=56, an intense variation of chromosomal morphology (karyotypic formula) has been documented in Pimelodus species. In the present study, we analyzed karyotypes of 20 specimens, identified as Pimelodus blochii Valenciennes, 1840 and collected from the lower courses of the Tapajós, Amazonas and Trombetas Rivers. The karyotypes were characterized by Giemsa conventional staining, C-banding, silver staining (Ag-NOR) and fluorescent in situ hybridization (FISH) with 5S and 18S rDNA probes. The karyotypes showed 2n=56 chromosomes in fish from the Tapajós River. In contrast, fish from the Amazonas and Trombetas Rivers had 2n=58. The nucleolus organizing regions were labeled on the short arm of an acrocentric chromosome as demonstrated by silver staining and FISH. Signals for 18S and 5S rDNA were co-localized on one chromosome pair. Our results demonstrate karyotypic divergence between Tapajós and Amazonas-Trombetas populations of P. blochii, interpreted as supporting the existence of a species complex in this taxon

A database of freshwater fish species of the Amazon Basin

The Amazon Basin is an unquestionable biodiversity hotspot, containing the highest freshwater biodiversity on earth and facing off a recent increase in anthropogenic threats. The current knowledge on the spatial distribution of the freshwater fish species is greatly deficient in this basin, preventing a comprehensive understanding of this hyper-diverse ecosystem as a whole. Filling this gap was the priority of a transnational collaborative project, i.e. the AmazonFish project - https://www.amazon-fish.com/. Relying on the outputs of this project, we provide the most complete fish species distribution records covering the whole Amazon drainage. The database, including 2,406 validated freshwater native fish species, 232,936 georeferenced records, results from an extensive survey of species distribution including 590 different sources (e.g. published articles, grey literature, online biodiversity databases and scientific collections from museums and universities worldwide) and field expeditions conducted during the project. This database, delivered at both georeferenced localities (21,500 localities) and sub-drainages grains (144 units), represents a highly valuable source of information for further studies on freshwater fish biodiversity, biogeography and conservation

Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species

The Neotropical catfish genus Tympanopleura, previously synonymized within Ageneiosus, is revalidated and included species are reviewed. Six species are recognized, two of which are described as new. Tympanopleura is distinguished from Ageneiosus by having an enlarged gas bladder not strongly encapsulated in bone; a prominent pseudotympanum consisting of an area on the side of the body devoid of epaxial musculature where the gas bladder contacts the internal coelomic wall; short, blunt head without greatly elongated jaws; and smaller adult body size. Species of Tympanopleura are distinguished from each other on the basis of unique meristic, morphometric, and pigmentation differences. Ageneiosus melanopogon and Tympanopleura nigricollis are junior synonyms of Tympanopleura atronasus. Tympanopleura alta is a junior synonym of Tympanopleura brevis. A lectotype is designated for T. brevis. Ageneiosus madeirensis is a junior synonym of Tympanopleura rondoni. Tympanopleura atronasus, T. brevis, T. longipinna, and T. rondoni are relatively widespread in the middle and upper Amazon River basin. Tympanopleura cryptica is described from relatively few specimens collected in the upper portion of the Amazon River basin in Peru and the middle portion of that basin in Brazil. Tympanopleura piperata is distributed in the upper and middle Amazon River basin, as well as in the Essequibo River drainage of Guyana

A new species of Pimelodus LaCépède, 1803 (Siluriformes: Pimelodidae) from rio Itacaiunas, rio Tocantins basin, Brazil

Pimelodus luciae is described from rio Itacaiunas, rio Tocantins basin. The new species exhibits a unique spotted pigmentation pattern for Pimelodidae. Pimelodus luciae differs further from remaining valid Pimelodus species by the following combination of characters: the relatively short distance between the posterior nostril and the anterior orbital border; dorsal surface of the supraoccipital process rounded; horizontal orbital diameter greater than interorbital distance; and distal portion of dorsal fin hyaline. Pimelodus luciae is known only from the type-locality. Copyright © 2010 Magnolia Press

A new species of Nemuroglanis (Siluriformes: Heptapteridae) from the rio Guariba, rio Madeira basin, Brazil

Nemuroglanis furcatus is described from streams of the rio Guariba, a clear water tributary of the rio Aripuanã, rio Madeira basin in Brazil. Nemuroglanis furcatus can be distinguished from its congeners by the possession of a long lateral line, reaching the middle portion of the adipose-fin base; a narrow posterior cranial fontanel (16 to 27% of its length); and the anterior border of pectoral bridge with a pointed contour. The plesiomorphic state of some of the synapomorphies for Nemuroglanis in N. furcatus suggests that this species might be the sister-group to the remaining species of the genus. A key for all four valid species of Nemuroglanis species is provided. © 2011. Magnolia Press