Ricardo M. C. Castro

Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling

BackgroundWith nearly 1,100 species, the fish family Characidae represents more than half of the species of Characiformes, and is a key component of Neotropical freshwater ecosystems. The composition, phylogeny, and classification of Characidae is currently uncertain, despite significant efforts based on analysis of morphological and molecular data. No consensus about the monophyly of this group or its position within the order Characiformes has been reached, challenged by the fact that many key studies to date have non-overlapping taxonomic representation and focus only on subsets of this diversity.ResultsIn the present study we propose a new definition of the family Characidae and a hypothesis of relationships for the Characiformes based on phylogenetic analysis of DNA sequences of two mitochondrial and three nuclear genes (4,680 base pairs). The sequences were obtained from 211 samples representing 166 genera distributed among all 18 recognized families in the order Characiformes, all 14 recognized subfamilies in the Characidae, plus 56 of the genera so far considered incertae sedis in the Characidae. The phylogeny obtained is robust, with most lineages significantly supported by posterior probabilities in Bayesian analysis, and high bootstrap values from maximum likelihood and parsimony analyses.ConclusionA monophyletic assemblage strongly supported in all our phylogenetic analysis is herein defined as the Characidae and includes the characiform species lacking a supraorbital bone and with a derived position of the emergence of the hyoid artery from the anterior ceratohyal. To recognize this and several other monophyletic groups within characiforms we propose changes in the limits of several families to facilitate future studies in the Characiformes and particularly the Characidae. This work presents a new phylogenetic framework for a speciose and morphologically diverse group of freshwater fishes of significant ecological and evolutionary importance across the Neotropics and portions of Africa.

Diversidade da ictiofauna do Alto Rio Paraná: composição atual e perspectivas futuras

Langeani, F., Castro, R.M.C., Oyakawa, O.T., Shibatta, O.A., Pavanelli, C.S. & Casatti, L. Ichthyofauna diversity of the upper rio Parana: present composition and future perspectives. Biota Neotrop. Sep/Dez 2007 vol. 7, no. 3 http://www.biotaneotropica.org.br/v7n3/pt/abstract?article+bn03407032007. ISSN 1676-0603. A synthesis concerning fishes from Upper Parana River basin is presented, based on data from fish-collections, literature, and new field samples. Three hundred and ten species, pertaining to 11 orders and 38 families, are referred to the drainage, elevating anterior estimates. Concerning total species, 236 (76.1%) are autochthonous, 67 (21.6%) are allochthonous, and seven (2.3%) are exotic. Principal causes of occurrence of non-native species are: a) dispersal from the Lower Parana, after the construction of Itaipu dam, and b) escapes from aquaculture farms. Most species (65%) are small-sized, having less than 21 cm of length, and the great majority occurs only in headwaters and small streams. One of the best known and most studied in Brazil, Upper Parana ichthyofauna richness is far from reaching actual numbers, considering the exponential elevation of species presented herein. Indeed, in the last years various new species have been described and around 50 other species, already recognized as new, are now under description. The improvement on the knowledge about Upper Parana ichthyofauna is proportional to the number of researchers involved with studies in the area and, unequivocally, reflects recent initiatives stimulating and incrementing taxonomic research, and also improving access to fish collections and to poor or never-sampled areas. However, if we are going to maintain the number of species descriptions per year of last decade, the 50 new species already recognized, will be described only in the next ten years, a period too long. In consequence it is very important that scientific community and grant agencies find and offer initiatives in order to elevate the number of new taxa descriptions per year.

Peixes de riacho do parque estadual Morro do Diabo, Bacia do Alto Rio Paraná, SP

AbstractResumo Stream fishes of the Morro do Diabo State Park, Upper Parana River basin, SP.A survey of the fish species in the streams of the Morro do Diabo State Park was performed. Four first and second order streams were sampled and 22 fish species and 1,573 individuals were collected, belonging to five orders and 11 families. A predominance of Order Siluriformes, followed by Characiformes was registered. Based on general aspects of their biology, the fish species were classified in eight guilds. The studied species are able to use several food sources and microhabitats available in these environments, being particularly favored by their small size. An identification key for the species, together with illustrations of their live coloration is provided.Peixes de riacho do Parque Estadual Morro do Diabo, bacia do Alto rio Parana, SPNeste trabalho foi realizado um levantamento das especies de peixes de riacho que ocorrem no Parque Estadual Morro do Diabo. Quatro riachos foram amostrados, de primeira a segunda ordem, onde foram coletadas 22 especies, pertencentes a cinco ordens e 1 1 familias, num total de 1.573 individuos. Foi registrado o predominio da Ordem Siluriformes, seguida por Characiformes. Com base em aspectos gerais da biologia das especies de peixes, as mesmas foram classificadas em oito guildas. De modo geral, as especies estudadas sao capazes de utilizar diversos recursos alimentares e micro-habitats disponiveis nesses ambientes, sendo particularmente favorecidas pelo pequeno porte apresentado. Chave de identificacao e fotos de exemplares recem-coletados de toda s as especies de peixes sao fornecidas.

Estrutura e composição da ictiofauna de riachos do rio Paranapanema, Sudeste e Sul do Brasil

Seventeen 100 m long streams stretches, none of an order higher than three, were sampled to both sides of the main channel of Rio Paranapanema in the States of Sao Paulo and Parana, southeastern and southern Brazil. Each stream stretch had its midpoint located with a GPS satellite receiver and had its fish fauna sampled via a standardized environmental data and fish collection methodology (primarily utilizing electrofishing) with the aim of providing the following information about each stream: 1) the taxonomic composition of the fish fauna and the contribution of each species in that stream in terms of both number of individuals and biomass; 2) a photographic documentation of the live coloration of representative speci-mens of each collected species; and 3) the description of each sampled environment, with colored photographic illustra-tions and details of the main biotic and abiotic parameters. Overall 3,683 fishes were collected, belonging to six orders, 16 families, 37 genera, and 52 species, with a total biomass of 16.8 kg. Of the collected species, approximately 36% were Siluriformes, 36% Characiformes, 11% Gymnotiformes, 10% Perciformes, 4% Cyprinodontiformes, and 2% Synbranchiformes. The most abundant species in terms of total number of individuals were Astyanax altiparanae (15.2%) and Astyanax sp. 1 (12.3%); The species with the largest biomasses were Astyanax altiparanae (28%) and Geophagus brasiliensis (13%). In terms of abundance and biomass collected for each family, the Characidae was clearly the predominant family followed by the Loricariidae, Pimelodidae, and Cichlidae. Among the sampled stream stretches, locality 14 with 24 species and locality 13 with five species yielded the highest and lowest richness in terms of species numbers, respectively. This coincides with the values obtained for the Shannon-Wienner index of specific diversity (H´ = 0.99 and 0.32, respectively). The median species richness for all streams stretches was 11. In the species richness estimate by extrapolation for all 17 sampled stream stretches, a value of 69 species was obtained (with a standard error of four) indicating the need for an additional moderate sampling effort to reach the asymptote of the curve. Of the 52 collected species, eight (approximately 15% of the total) are clearly new to science and five other species (approximately 10% of the total) are of indefinite taxonomic status and require further analysis. Three of the captured species are introduced (approximately 6% of the total). Analysis of the trophic and spatial structure of the studied fish fauna indicates that the 10 numerically dominant species in the sampled streams can be grouped into four guilds that are in decreasing order of numeric importance: nektonic omnivores; benthonic invertivores; periphytovores; and benthonic omnivores. An identification key for all the species of fish collected during this study it is provided.

Testing the ecomorphological hypothesis in a headwater riffles fish assemblage of the rio São Francisco, southeastern Brazil

The ecomorphology of 14 fish species resident in a headwater riffles area of the Sao Francisco river, southeastern Brasil, was analyzed and combined with diet and feeding behavior data, previously obtained by us. The three larger species groups formed in the ecomorphological analysis were found to reflect primarily microhabitat occupation in the following manner: a) nektonic characids with compressed bodies, lateral eyes and lateral pectoral fins, with diurnal and opportunistic feeding habits (Astyanax rivularis, Bryconamericus stramineus, and Bryconamericus sp.); b) nektobenthic characiforms and siluriforms with fusiform bodies and expanded pectoral fins, including sit-and-wait characidiins, predators of aquatic insect larvae (Characidium fasciatum and Ch.zebra), as well as the algae grazing parodontids (Apareiodon ibitiensis and Parodon hilarii), and also the heptapterid and trichomycterid catfishes that practice substrate speculation and feed on benthic aquatic insect larvae (Cetopsorhamdia iheringi, Imparfinis minutus, Rhamdia quelen, and Trichomycterus sp.); c) benthic species with depressed bodies, suctorial oral discs, dorsal eyes, and horizontal pectoral fins, represented by the periphytivorous loricariid catfishes (Hisonotus sp., Harttia sp., and Hypostomus garmani). Correlation between diet and general morphology was not significant in our analysis, unless when the analyzed set included only nektonic and benthic species, indicating that the lack of correlation between these factors is most pronounced in the group of nektobenthic species. The unequivocal case of morphological convergence found between the nektobenthic Characidiinae and Parodontidae is a clear example of the integration between phylogenetic information and ecomorphology, and provides a way to objectively identify cases of morphological and adaptive convergence and divergence. Furthermore, the general congruence between the ecomorphological results and the independently obtained ecological data about the analyzed fish species in their natural environment seems to be strong evidence in favor of the proposed predictive capabilities of the ecomorphological hypothesis.

Stream fish, water and habitat quality in a pasture dominated basin, southeastern Brazil

A fish survey in 35 stream reaches (from 1st to 3rd order) with physicochemical and habitat assessment in the São José dos Dourados system, southeastern Brazil, was conducted. Most of the basin land cover (77.4%) is used for pasture. From the sampled stream reaches, 24 were of good physicochemical quality, 10 of fair quality, and only one of poor quality. A habitat assessment showed that 10 stream reaches were considered fair, 22 were poor, and 3 were very poor. Fifty species were collected and their abundances showed strong correlation with habitat descriptors. In addition to the correlation between fish abundance and habitat, some species also showed optimal distribution related to the degree of physical habitat conservation. Streams located in this region experience organic pollution, but the most important aspect is the decline of the instream physical habitat condition, especially in first order streams, which negatively affects coarse substrates and water column dependent fish species. Effluent control, riparian vegetation restoration programs, siltation control and adequate sustainable soil use are practices which could mitigate such impacts.

New Corydoradine Catfish (Siluriformes: Callichthyidae) from the Upper Paraná and São Francisco: The Sister Group of Brochis and Most of Corydoras Species

Abstract Corydoras difluviatilis, new species, is described from the upper rio Paraná and the upper rio São Francisco, Brazil. The new taxon differs from its congeners by three exclusive features: the posterior pectoral-spine serrations restricted to its proximal half, and the parapophyses of the fourth free vertebra reduced and separated from each other, not fused into a haemal arch. The new species has several plesiomorphic character states relative to the assemblage composed of Brochis and most Corydoras species, such as absence of contact between the supraoccipital and nuchal plate, reduction of the ossified portion of hypobranchial 2, and well-developed mesial expansions of the first and second infraorbitals, indicating its basalmost position within the genus.

New Species of Astyanax (Ostariophysi: Characiformes: Characidae) from the Upper Rio Paraná System, Brazil

Abstract Astyanax bockmanni, a new species of characid, is widespread in streams in the upper Rio Paraná system of central, southeastern, and southern Brazil. Samples of the species were identified by previous authors as A. eigenmanniorum, a species originally described from far southern Brazil. Astyanax bockmanni differs from A. eigenmanniorum and all congeners in the combination of morphometric, meristic, and pigmentary features and details of oral dentition. Uncertainties concerning the generic placement of Astyanax paranahybae are discussed, and it is proposed that the species is a member of a clade within the Characidae that does not include Astyanax. Astyanax bockmanni, uma nova espécie de caracídeo, é amplamente distribuída em riachos do Alto Rio Paraná, nas regiões centro-oeste, sudeste e sul do Brasil. Amostras dessa espécie foram previamente identificadas por diversos autores como A. eigenmanniorum, uma espécie originalmente descrita do extremo sul do Brasil. Astyanax bockmanni difere de A. eigenmanniorum e demais congêneres por uma combinação de caracteres morfométricos e de pigmentação, além de detalhes da dentição oral. Incertezas quanto ao posicionamento genérico de Astyanax paranahybae são discutidas e propõe-se que a espécie seja membro de um clado de Characidae que não inclui Astyanax.

Lophiobrycon weitzmani, a new genus and species of glandulocaudine fish (Characiformes: Characidae) from the rio Grande drainage, upper rio Paraná system, southeastern Brazil

A new genus and species of glandulocaudine, Lophiobrycon weitzmani, is described based on specimens collected in headwater tributary streams of the rio Grande, upper rio Parana system, State of Minas Gerais, southeastern Brazil. The inclusion of the new species in the phylogeny of the subfamily Glandulocaudinae proposed by Weitzman & Menezes (1998), reveals a sister group relationship between the new genus and the monophyletic group composed of Glandulocauda and Mimagoniates that currently form the tribe Glandulocaudini. The new species can be readily distinguished from all other species of the tribe by the autapomorphic presence in adult male individuals (with more than 23.9 mm standard length) of an adipose-fin whose base extends for almost the entire distance between the posterior terminus of the base of the dorsal fin and the base of the upper lobe of the caudal fin and averages approximately 25% standard length, along with the presence of globular expansions formed by the lepidotrichia and hypertrophied soft tissue in the middle portions of the first and second pectoral-fin rays. The diagnosis of the tribe Glandulocaudini is modified to accommodate the new genus.

The blind catfish from the caves of Chapada Diamantina, Bahia, Brazil (Siluriformes: Heptapteridae): description, anatomy, phylogenetic relationships, natural history, and biogeography

, a new troglobitic heptapterid catfish, is described from the caves of Chapada Diamantina, State of Bahia,northeastern Brazil. This species, although frequently cited in the scientific literature along the last seventeen years, remainedundescribed largely due to its uncertain phylogenetic affinities. The generic assignment of