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Belém, Brazil

Mattos J.L.,Federal University of Rio de Janeiro | 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.

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.

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 | 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

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