Setor de Ictiologia
Setor de Ictiologia
Becker F.G.,Federal University of Rio Grande do Sul |
De Fries L.C.C.,Federal University of Rio Grande do Sul |
Ferrer J.,Federal University of Rio Grande do Sul |
Bertaco V.A.,Federal University of Rio Grande do Sul |
And 5 more authors.
Brazilian Journal of Biology | Year: 2013
The aquatic habitats of the Taquari-Antas river basin (in the Patos Lagoon basin, southern Brazil) are under marked environmental transformation because of river damming for hydropower production. In order to provide an information baseline on the fish fauna of the Taquari-Antas basin, we provide a comprehensive survey of fish species based on primary and secondary data. We found 5,299 valid records of fish species in the basin, representing 119 species and 519 sampling sites. There are 13 non-native species, six of which are native to other Neotropical river basins. About 24% of the total native species are still lacking a taxonomic description at the species level. Three native long-distance migratory species were recorded (Leporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis), as well as two potential mid-distance migrators (Parapimelodus nigribarbis and Pimelodus pintado). Although there is only one officially endangered species in the basin (S. brasiliensis), restricted range species (21.7% of total species) should be considered in conservation efforts.
Volcan M.V.,Instituto Pro Pampa IPPampa |
Cheffe M.M.,Setor de Ictiologia |
Lanes L.E.K.,Instituto Pro Pampa IPPampa |
Burns M.D.M.,Grande Rio University
Check List | Year: 2010
We present here the record of Dormitator maculatus (Bloch, 1792) to the Patos-Mirim lagoon system, Rio Grande do Sul, Brazil. This is also the southernmost occurrence in South America, extending species range ca. 150 km from the previously known localities. © 2010 Check List and Authors.
Azevedo M.A.,Setor de Ictiologia |
Malabarba L.R.,Federal University of Rio Grande do Sul |
Burns J.R.,George Washington University
Neotropical Ichthyology | Year: 2010
The reproductive biology and development of the gill gland are described for Macropsobrycon uruguayanae, an inseminating characid species of the tribe Compsurini, subfamily Cheirodontinae. Between April 2001 and March 2002, 117 males and 143 females of this species were collected in the rio Ibicui, Uruguay basin in the State of Rio Grande do Sul, Brazil. Reproductively active individuals were present during most months sampled, indicating lack of a well-defined seasonal reproductive period. Several maturing females were found to be inseminated before completing full maturation. Histological analyses demonstrated spermatozoa within the ovaries of females in different stages of gonadal maturation collected during most months. No immature females had inseminated ovaries. Standard length at first gonadal maturation was estimated to be 24 mm for both males and females. Mean absolute fecundity was 191.08 (± 48.83 SD) oocytes per female, one of the lowest among characids. Relative fecundity was 0.539 (± 0.069 SD) oocytes per mg weight of the female, a value similar to that found for the majority of species of Cheirodontinae. The presence of two cohorts of oocytes within ovaries ofM. uruguayanae indicates synchronous development, with total spawning. The mean diameter of mature oocytes was 0.6711 (± 0.1252 SD) mm, smaller than that found for the majority of species of Characidae. Gill glands occurred in all mature males, as well as in males undergoing advanced maturation. In the latter case, fewer gill filaments comprised the glands. Gill glands were not observed in immature males, males undergoing the initial stages of maturation, or in any female. A given gill gland may comprise as many as 24 filaments of the lateral hemibranch of the first gill arch. Secondary lamellae within most of the gill gland are greatly reduced, with columnar cells being present between them. These columnar cells contain abundant vesicles, suggesting secretory activity. The morphology of the gill gland of M. uruguayanae resembles that found in the majority of characid species that possess this structure. © 2010 Sociedade Brasileira de Ictiologia.
Silva D.S.,Federal University of Pará |
Peixoto L.A.W.,Setor de Ictiologia |
Pieczarka J.C.,Federal University of Pará |
Wosiacki W.B.,Setor de Ictiologia |
And 2 more authors.
Neotropical Ichthyology | Year: 2015
Eigenmannia species are widely distributed in the Neotropics, with eight valid species currently recognized. Populations of Eigenmannia from three locations in the eastern Amazon were investigated using cytogenetic and morphological techniques, revealing two taxa designated here as Eigenmannia sp. “A” and Eigenmannia sp. “B”. The species differ in three morphometric characters, two meristic characters, and one osteological character. Eigenmannia sp. “A” presents 2n = 34 (22 m/sm+12 st/a) and Eigenmannia sp. “B” presents 2n = 38 (14 m/sm+24st/a) and simple differentiated sex chromosomes of the type XX/ XY. In both species the Constitutive Heterochromatin (CH) rich in A-T bases is distributed in the centromeric region of all chromosomes. Eigenmannia sp. “B” also presents CH blocks in the interstitial region of chromosome pairs 8, 9 and X which are positively stained with CMA3, indicating G-C rich regions. The NOR is located on the short arm of chromosome pair 17 of Eigenmannia sp. “A” and on the short arm of pair 14 of Eigenmannia sp. “B”. FISH with rDNA probes hybridized to different-sized regions between homologs, suggesting heteromorphism. The differentiation of the X chromosome in Eigenmannia sp. “B” could be the result of amplification of repetitive DNA sequences. © 2015 Sociedade Brasileira de Ictiologia.
Da de Santana C.,Smithsonian Institution |
Vari R.P.,Smithsonian Institution |
Wosiacki W.B.,Setor de Ictiologia
PLoS ONE | Year: 2013
Alternative hypotheses had been advanced as to the components forming the elongate fin coursing along the ventral margin of much of the body and tail from behind the abdominal region to the posterior margin of the tail in the Electric Eel, Electrophorus electricus. Although the original species description indicated that this fin was a composite of the caudal fin plus the elongate anal fin characteristic of other genera of the Gymnotiformes, subsequent researchers proposed that the posterior region of the fin was formed by the extension of the anal fin posteriorly to the tip of the tail, thereby forming a "false caudal fin." Examination of ontogenetic series of the genus reveal that Electrophorus possesses a true caudal fin formed of a terminal centrum, hypural plate and a low number of caudal-fin rays. The confluence of the two fins is proposed as an additional autapomorphy for the genus. Under all alternative proposed hypotheses of relationships within the order Gymnotiformes, the presence of a caudal fin in Electrophorus optimized as being independent of the occurence of the morphologically equivalent structure in the Apteronotidae. Possible functional advantages to the presence of a caudal fin in the genus are discussed. © 2013.
Azevedo M.A.,Setor de Ictiologia |
Fialho C.B.,Federal University of Rio Grande do Sul |
Malabarba L.R.,Federal University of Rio Grande do Sul
Journal of Fish Biology | Year: 2016
The reproductive biology of two inseminating Glandulocaudini species, Mimagoniates microlepis and Mimagoniates rheocharis, was investigated and compared with reproductive patterns described for other inseminating and non-inseminating characids, hypothesizing the evolutionary history of these reproductive traits. The long reproductive period, with higher activity in colder months, distinguishes the reproductive strategy of these species when compared with most characiforms. The M. rheocharis population was structured in two groups of males throughout the year, mature males with high gonado-somatic index (IG = 2·0 and 4·4) and immature and maturing males with low IG values (0·0 and 1·2). Mimagoniates rheocharis and M. microlepis showed the lowest absolute mean fecundities known for characids, indicating that inseminating species allocate less energy to oocyte production and reinforcing the hypothesis that insemination has an adaptive advantage, which provides a higher chance of fertilization. © 2016 The Fisheries Society of the British Isles
Birindelli J.L.O.,University of Sao Paulo |
Fayal D.F.,Setor de Ictiologia |
Wosiacki W.B.,Setor de Ictiologia
Neotropical Ichthyology | Year: 2011
The genus Hassar (Doradidae) is diagnosed by a single exclusive feature: basioccipital with ventral ring-like arch surrounding aorta; and by the combination of several non-exclusive characters, including dark blotch in distal half of anterior branched rays of dorsal fin, and anteriormost postinfranuchal scutes reduced in size. Three nominal species are recognized and redescribed in Hassar: H. orestis from the Orinoco, Essequibo and Amazonas basins, excluding Tocantins and middle to upper Xingu drainages; H. wilderi from Tocantins; and H. affinis from northeastern Brazil, including Turiaçu, Pindaré-Mearim, Itapecuru and Parnaíba drainages. The nominal Hemidoras notospilus and Hassar ucayalensis are recognized as junior synonyms of Hassar orestis; Hassar woodi is considered a junior synonym of H. affinis; Hassar iheringi is recognized as a junior synonym of H. wilderi, and its type locality as originally reported is considered incorrect. A fourth new species, Hassar gabiru, is described from middle to upper Xingu river basin. Hassar is considered to be the sister taxon of Anduzedoras + Leptodoras. A detailed anatomical description and discussion of the phylogenetic relationships of Hassar among fimbriate-barbel doradids are provided. © 2011 Sociedade Brasileira de Ictiologia.
Azevedo M.A.,Setor de Ictiologia
Iheringia - Serie Zoologia | Year: 2010
In this study, I investigated the reproductive biology of fish species from the family Characidae of the order Characiformes. I also investigated the relationship between reproductive biology and body weight and interpreted this relationship in a phylogenetic context. The results of the present study contribute to the understanding of the evolution of the reproductive strategies present in the species of this family. Most larger characid species and other characiforms exhibit a reproductive pattern that is generally characterized by a short seasonal reproductive period that lasts one to three months, between September and April. This is accompanied by total spawning, an extremely high fecundity, and, in many species, a reproductive migration. Many species with lower fecundity exhibit some form of parental care. Although reduction in body size may represent an adaptive advantage, it may also require evolutionary responses to new biological problems that arise. In terms of reproduction, smaller species have a tendency to reduce the number of oocytes that they produce. Many small characids have a reproductive pattern similar to that of larger characiforms. On the other hand they may also exhibit a range of modifications that possibly relate to the decrease in body size and the consequent reduction in fecundity. Examples of changes in the general reproductive pattern include the following: reduction in the size of mature oocytes; increase in fecundity; production of several batches of oocytes; an extended reproductive period or even continuous reproduction that allows individuals to reproduce more than once a year; high growth rates; rapid recruitment of juveniles; presence of more than one reproductive cohort that increases the sexually active population; and multiple independent development of insemination as a reproductive strategy. These changes are possibly associated with adaptive pressures that are related to the reduction in body size. In addition, such reproductive characteristics or novelties may reflect the phylogenetic history of a given species.
Mattos J.L.,Federal University of Rio de Janeiro |
Schindler I.,Berlin |
Ottoni F.P.,Federal University of Rio de Janeiro |
Cheffe M.M.,Setor de Ictiologia
Vertebrate Zoology | Year: 2014
Crenicichla lucenai sp. n. from the upper Rio das Antas basin, dos Patos lagoon system, southern Brazil is here described. The new species is similar to C. punctata and C. maculata. It is distinguished from both these species by the conspicuous pattern of dark brown irregular lines extending from longitudinal stripe to ventral profile (versus irregular lines absent). In addition, C. lucenai can be distinguished from C. punctata by the absence of dots on the sides of its head. © 2014 Senckenberg Gesellschaft für Naturforschung.
Marceniuk A.P.,Federal University of Pará |
Caires R.A.,University of Sao Paulo |
Wosiacki W.B.,Setor de Ictiologia |
Di Dario F.,Federal University of Rio de Janeiro
Biota Neotropica | Year: 2013
The tropical western South Atlantic, which includes a substantial portion of the Brazilian Exclusive Economic Zone, is a region of endemism broadly recognized as being of prime importance for the conservation of the marine biodiversity. The north coast of Brazil, which comprises the states of Amapá, Pará and Maranhão from the mouth of the rio Oiapoque to the mouth of the rio Parnaíba, harbors the largest continuous mangrove in the world, with approximately 8,900 km2. The high discharge of freshwater and continental sediments in the delta of the Amazonas affects the regime of tides, ocean currents, and several oceanographic processes of the north coast, with direct impact on the composition of the biota found in the region. Despite its economic value and intrinsic biological relevance, several aspects of the diversity of the marine and estuarine fishes of the region are poorly known. This situation results mainly from a historical imbalance in terms of the number of studies devoted to increasing the knowledge of the marine biota along the Brazilian coast, such as those dealing with species inventory and taxonomic revisions, which are typically concentrated in the south and southwestern portions of the country. The scientific production focused on marine organisms of the north coast is also imbalanced, and reflects the relatively small number of taxonomists and research groups working on that subject. The insufficient knowledge of the biodiversity of the marine and estuarine fishes of the north coast is an impediment to the implementation of adequate public policies aimed at the management of natural resources in the region. In the long term, that situation is potentially harmful in terms of conservation of a still poorly known biota. A better understanding of the marine fish fauna of the north coast of Brazil will be achieved only through the investment in scientific research and personnel training in systematics and biogeography, coupled with the modernization of the current infrastructure and expansion of scientific collections of the region.