Revisão taxonômica de Moenkhausia grandisquamis e M. xinguensis (Teleostei: Characiformes: Characidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A new species of Hemigrammus from the upper Rio Tapajos basin in Brazil (Teleostei : Characiformes : Characidae)

Hemigrommus silimoni is described from the Rio Juruena, upper Rio Tapajos basin, Mato Grosso State, Brazil. The new species is distinguished from all congeners, and in fact from the remaining Characidae, by the autapomorphic presence of an ocellus-like blotch on the caudal-fin dorsal lobe. The high level of fish endemicity In the Rio Juruena (upper Rio Tapajos basin) is discussed.

Knodus dorsomaculatus (Characiformes: Characidae), a new species from Teles Pires River, Tapajos River basin, Brazil

Knodus dorsomaculatus, a new species, is described from Teles Pires River, a tributary of the Tapajos River, Brazil. It can be distinguished from its congeners by the presence of a conspicuous dark blotch on the base of the first five branched dorsal fin rays and the presence of ii,9 dorsal fin rays. Additional comparisons between K. dorsomaculatus and its congeners are presented.

New species of Moenkhausia Eigenmann (Characiformes: Characidae) from Rio Xingu and Rio Tapajos basins, Brazil, with comments on a putative case of polymorphic Batesian mimicry

A new species of Moenkhausia is described from Rio Xingu and Rio Tapajos basins, Brazil. The new species is distinguished from its congeners, except from Moenkhausia moisae, by having more scales in the lateral series, 43-47 (v. 23-41 in the remaining congeners). The new species is distinguished from M. moisae by its colour pattern, which consists of a dark midlateral stripe, and an asymmetrical caudal blotch (inconspicuous or faded in specimens from the Rio Arinos) continuous with the midlateral stripe (v. narrow dark midlateral line and conspicuous, regularly rounded and symmetrical blotch not continuous with the midlateral line). The new species is putatively assumed to be mimetic to Jupiaba apenima, in the Rio Xingu and Rio Teles Pires drainages, and to Jupiaba yarina in the Rio Arinos. The two species of Jupiaba are sympatric and remarkably similar in size, general external morphology and colouration to the new species. A small difference occurs in the colouration between the two species of Jupiaba and is also observed in the two respectively sympatric morphotypes of the new species of Moenkhausia. The occurrence of polymorphic Batesian mimicry is therefore discussed for neotropical freshwater fishes. (C) 2009 The Authors Journal compilation (C) 2009 The Fisheries Society of the British Isles

Two new species of Jupiaba (Characiformes: Characidae) from the rio Tapajos and rio Madeira drainages, Brazil, with an identification key to species of the genus

Two new species of Jupiaba Zanata are described from Brazil. Jupiaba iasy, new species, is described from rio Teles Pires and rio Jamanxim, tributaries of rio Tapajos, and from rio Aripuana, in the rio Madeira drainage. It is distinguished from its congeners by its color pattern consisting of a single posteriorly displaced dark crescent-shaped humeral blotch, situated over the first 5 to 7 lateral line scales, and an inconspicuous dark spot at the end of caudal peduncle. It also differs from all remaining Jupiaba for the following combination of characters: 34-36 lateral line scales, 19-21 branched anal-fin rays, 8-10 predorsal scales arranged in a regular row, 6 horizontal series of scales above and 4 series below lateral line, body depth 32.3-36.1% of SL, and absence of filamentous rays in the first dorsal and anal-fin rays. Jupiaba paranatinga, new species, is described from rio Teles Pires, tributary of rio Tapajos. It is distinguished by having 34-35 lateral line scales, two vertically elongated humeral blotches, a conspicuous caudal spot at the end of the caudal peduncle, extending over 8-10 median caudal-fin rays, eye diameter 43.7-46.9% of HL, and relatively low body depth (31.3-35.5% of SL). Additionally, comments on the putative relationships of the new species with their congeners and an updated key to the species of the genus are provided.

A new genus and species of inseminating characid fish from the rio Xingu basin (Characiformes: Characidae)

Phallobrycon adenacanthus, is described as a new genus and species belonging to Clade A characids of Malabarba & Weitzman (2003). The new taxon is the only characid possessing two developed spines on unbranched portions of fifth, sixth and seventh anal-fin rays associated with intumescent glandular tissue on the anterior portion of the anal fin of sexually mature males. Other non-exclusive diagnostic features of the new genus (observed in male specimens) are: urogenital papilla modified into a copulatory organ, absence of pelvic-fin hooks and glandular tissue not organized into an organ. The presence of these features in members of Clade A and other characids is discussed in order to hypothesize the relationships of Phallobrycon.

Threatened fishes of the world: Brycon nattereri Gunther, 1864 (Characidae)

Brycon nattereri (Ostariophysi: Characiformes: Characidae), a threatened South American freshwater fish, occurs in the Parana, Tocantins and Sao Francisco river basins in central Brazil. It is a middle-sized (up to 50 cm SL), omnivorous species, which occurs in swift, clear-water rivers with well-preserved riparian vegetation. Main threats to the species are water pollution, dam building, and deforestation.

Diet of Astyanax paranae (Characidae) in streams with different riparian land covers in the Passa-Cinco River basin, southeastern Brazil

An analysis of the diet of Astyanax paranae Eigenmann, 1914 in nine streams located in the Passa-Cinco River basin (upper Parana River system) was performed to investigate the feeding habits of this species, check for possible spatial variations in diet and to investigate the influence of riparian vegetation in the composition of the diet. Stomach contents of 243 specimens were analyzed by the methods of relative frequency of occurrence and volume, and the diet was characterized by the alimentary index (AI(i)). The species showed insectivorous feeding habits, with a predominance of terrestrial and aquatic insects in the diet, varying by location. In most streams, resources of allochthonous origin were the most consumed. The participation of aquatic insects and terrestrial plants were high in most streams, while terrestrial insects and invertebrates were highest in streams with a greater presence of riparian forest. The two streams located draining pasture fields were the only places were A. paranae consumed algae and macrophyte fragments. These results were corroborated by the analysis of similarity (ANOSIM): the descriptor "percentage of riparian forest" was the highest environmental influence on the diet of A. paranae. The study shows that riparian forest percentage on the stream reach determines the species diet composition, but A. paranae is also able to gather enough food resources in a variety of severely degraded environments.

The influence of captive breeding on the fatty acid profiles of Salminus hilarii (Characiformes: Characidae) eggs and larvae

In addition to the strong influence of the broodstock diet on the development and survival of offspring, domestication may also interfere with the larval life success. We obtained eggs from wild and domesticated Salminus hilarii females and domesticated males. Wild females were caught in the Tiete River and tributaries, and the domesticated females were born three years before the beginning of the experiment in the Ponte Nova Fish Farm. Animals from both groups were fed with the same feed to exclude feed variables. The eggs and larvae were sampled at 0, 8, 16, and 28 h after spawning (HAS), with the last sampling (28 HAS) coinciding with hatching time. After hatching, samplings proceeded at 32, 48, 66, and 96 HAS, with the last sampling (96 HAS) corresponding to the end of yolk sac consumption. Finally, the last experimental period was during the larvae exogenous feeding phase, at 102, 118, 166, and 214 HAS. Our data revealed that domestication of S. hilarii females influenced fatty acid (FA) metabolism during embryo and larva development. However, the structure of membrane phospholipid FA remained mostly stable, with changes principally in the neutral fraction. When the external conditions, mainly water and feed quality, remained constant, domestication of S. hilarii females did not significantly affect the structural FA composition but influenced the selectivity of consumption and/or storage of specific FA.

Immunohistochemical study of pituitary cells in wild and captive Salminus hilarii (Characiformes: Characidae) females during the annual reproductive cycle

Freshwater fish that live exclusively in rivers are at particular risk from fragmentation of the aquatic system, mainly the species that migrate upriver for reproduction. That is the case of Salminus hilarii, an important migratory species currently classified as “almost threatened” in the São Paulo State (Brazil), facing water pollution, dam construction, riparian habitat destruction and environmental changes that are even more serious in this State. Additionally, this species show ovulation dysfunction in captivity. Our studies focused on the identification and distribution of the pituitary cell types in the adenohypophysis of S. hilarii females, including a morphometric analysis that compares pituitary cells from wild and captive broodstocks during the reproductive annual cycle. The morphology of adenohypophysial cells showed differences following the reproductive cycle and the environment. In general, optical density suggested a higher cellular activity during the previtellogenic (growth hormone) and vitellogenic (somatolactin) stages in both environments. Additionally, the nucleus/cell ratio analysis suggested that growth hormone and somatolactin cells were larger in wild than in captive females in most reproductive stages of the annual cycle. In contrast, prolactin hormone showed no variation throughout the reproductive cycle (in both environments). Morphometrical analyses related to reproduction of S. hilarii in different environmental conditions, suggest that somatolactin and growth hormone play an important role in reproduction in teleost and can be responsible for the regulation of associated processes that indirectly affect reproductive status.

Two new species and a review of the inseminating freshwater fish genus Monotocheirodon (Characiformes: Characidae) from Peru and Bolivia

Two new species of inseminating freshwater fishes of the genus Monotocheirodon, family Characidae, are described from Peru. Males and females of both new species have an external, visually obvious urogenital papilla that was not detected in the females in previous studies, with this longer in males, which use it as an inseminating organ. A third inseminating species from Bolivia, Monotocheirodon pearsoni, unstudied in any detail since its original description in 1924, is redescribed. This latter species lacks an inseminating organ. Monotocheirodon is redescribed, its phylogenetic relationships are briefly discussed and it is suggested that it is possibly related to the stevardiin genera Ceratobranchia, Othonocheirodus, and Odontostoechus.

Immunohistochemical study of pituitary cells in wild and captive Salminus hilarii (Characiformes: Characidae) females during the annual reproductive cycle

Freshwater fish that live exclusively in rivers are at particular risk from fragmentation of the aquatic system, mainly the species that migrate upriver for reproduction. That is the case of Salminus hilarii, an important migratory species currently classified as “almost threatened” in the São Paulo State (Brazil), facing water pollution, dam construction, riparian habitat destruction and environmental changes that are even more serious in this State. Additionally, this species show ovulation dysfunction in captivity. Our studies focused on the identification and distribution of the pituitary cell types in the adenohypophysis of S. hilarii females, including a morphometric analysis that compares pituitary cells from wild and captive broodstocks during the reproductive annual cycle. The morphology of adenohypophysial cells showed differences following the reproductive cycle and the environment. In general, optical density suggested a higher cellular activity during the previtellogenic (growth hormone) and vitellogenic (somatolactin) stages in both environments. Additionally, the nucleus/cell ratio analysis suggested that growth hormone and somatolactin cells were larger in wild than in captive females in most reproductive stages of the annual cycle. In contrast, prolactin hormone showed no variation throughout the reproductive cycle (in both environments). Morphometrical analyses related to reproduction of S. hilarii in different environmental conditions, suggest that somatolactin and growth hormone play an important role in reproduction in teleost and can be responsible for the regulation of associated processes that indirectly affect reproductive status.

The American Characidae / by Carl H. Eigenmann.

v.43 (1917-1929) text

Ecologia alimentar e reprodutiva da piaba-do-rabo-amarelo, Astyanax cf. lacustris (Reinhardt, 1874) (Osteichthyes: Characidae) na Lagoa do Piató, Assu, Rio Grande do Norte, Brasil

The feeding habits and biological aspects of the reproductive cycle of two-spot astyanax, Astyanax cf. lacustris (Reinhardt, 1874) were investigated. Fish samples were captured on a monthly basis, using gillnets of 4 cm mesh size, from the Piató Lake, Assu, Rio Grande do Norte, during the period of September, 2006 to August, 2007. Physico-chemical parameters, such as, temperature, electrical conductivity and dissolved oxygen of the lake were registered. The monthly values of rainfall also were obtained. The 360 individuals captured, were measured, weighed, dissected, and stomach weight and the stage of gonadal maturity were registered. The stomach contents analyses were carried out based on volumetric method, points, frequency of occurrence and applying the Index of Relative Importance. The degrees of repletion of the stomachs were determined besides the Index of Repletion relating to feeding activity variations and frequency of ingestion with limnological parameters and rainfall. The food items identified were separated into distinct groups according to their origin. Sex ratio and Gonadosomatic Relation of females were verified to determine the spawning period and fecundity. The physico-chemical parameters presented the following annual mean values: temperature = 28.8ºC, electrical conductivity = 992.5 µS.cm-1; dissolved oxygen = 4.9 mg.L-1 during the study period. The annual mean of the rainfall was 63.5 mm. The results indicate that this species present an omnivorous feeding habit with a tendency towards insectivory, with an increase in feeding activity during the dry season. The aquatic oxygen to interfere very importance in the feeding activity than the others factors physico-chemicals of water and rainfall. There was a predominance of females, with a sex proportion of 1M:7F. The macroscopic characteristics of the ovaries and testicles revealed four stages of gonadal development: immature, maturing, mature and spent. A temporal variation was observed for the gonadal development of males and females. There was reproductive activity through out the year, with peaks in the months of February, April and June to correspond with the rain of precipitation of the region. The mean fecundity was 7.681 mature oocytes, varying from 4.476 to 12.036, with mean of 7.681. There was positive relation between fecundity and body mass. Condition Factor is not an efficient indicator of the reproductive period of this species. The species A. cf. lacustris is an opportunist and is well adapted to the conditions of the semi-arid Caatinga Biome

Efeito do fungo Metarhizium anisopliae (Metsch.) Sorok. (Deuteromycetes) para Astyanax scabripinnis (Jenyns, 1842) (Pisces: Characidae).

Avaliou-se o efeito de Metarhizium anisopliae (Metsch.) para Astyanax scabripinnis (Jenyns, 1842)(Pisces, Characidae), em condições de laboratório. Suspensões aquosas de conídios recémproduzidos, viáveis (viabilidade mínima 90%) e inviabilizados por meio de autoclavagem (121º C, 20 minutos, a 1 atm), na concentração de 6,5 x 1010 conídios/aquário (equivalente a 5 x 1015 conídios/ ha, que representa 1.000 vezes a concentração recomendada para o controle de cigarrinhas de pastagens, principal praga-alvo deste entomopatógeno no Brasil), foram aplicadas em aquários contendo A. scabripinnis. Foram analisadas amostras de água e dos peixes, dos quais foram dissecados as brânquias e o estômago, em diferentes intervalos de tempo, a fim de se avaliar a presença dos conídios. Observaram-se diariamente o comportamento e a mortalidade de peixes em ambos os tratamentos. Avaliou-se nos peixes sobreviventes a morfologia das células das brânquias e do fígado. Verificou-se que nas brânquias não houve alteração no número de conídios ao longo de 16 dias de contato, sendo que no estômago houve um ligeiro acréscimo inicial seguido de redução constante. A viabilidade dos conídios em todos os locais avaliados decresceu após 24 horas da aplicação. Constatou-se que não houve morte ou quaisquer alterações comportamentais após 30 dias de contato, indicando a ausência de efeitos adversos associados à capacidade do fungo em provocar infecção ou exercer efeitos tóxicos em ambos os organismos-teste.