A New Genus and Species of a Minute Suckermouth Armored Catfish (Siluriformes: Loricariidae) from the Rio Tocantins Drainage, Central Brazil: The Smallest Known Loricariid Catfish

Nannoplecostomus eleonorae, a new genus and species of a miniature suckermouth armored catfish, is described based on specimens collected from the karst region of Sao Domingos, upper Rio Tocantins basin, Goias State, central Brazil. The new genus and species can be diagnosed among loricariids by presenting a unique reductive pattern of lateral dermal plates, with most of the body covered by only three series of plates (viz., dorsal, mid-ventral, and ventral). Based on the available published phylogenetic studies for the family, we provisionally consider Nannoplecostomus eleonorae as being an incertae sedis taxon within Loricariidae. Achieving a maximum standard length of 22.2 mm SL, Nannoplecostomus eleonorae is the smallest known loricariid catfish, and a list of the remaining smallest loricariids is provided.

A New Species of Hypostomus (Siluriformes: Loricariidae) from the Upper Rio Paraguay Basin, Brazil

A new small Loricariidae, Hypostomus careopinnatus, is described from the Rio Taquari drainage, upper Rio Paraguay basin, Mato Grosso, Brazil. The new species can be easily distinguished from all congeners, except Hypostomus kids, by the absence of adipose fin. Hypostomus careopinnatus is distinguished from H. levis mainly by the presence of slender bifid teeth, with mesial cusp large and rounded, and lateral cusp small and pointed (vs. spoon-shaped teeth). The new species described herein completely lacks the adipose fin and also lacks the median pre-adipose plates in almost all specimens examined. The absence of adipose fin is probably an independent acquisition for Hypostomus careopinnatus and Hypostomus levis.

A New Species of Cascudinho of the Genus Hisonotus (Siluriformes: Loricariidae: Hypoptopomatinae) from the Upper Rio Tapajos Basin, Brazil

Hisonotus bockmanni, new species, is described based on specimens collected in a sandbank in the Rio Cururu, a tributary to the Rio Teles Pires, one of the rivers forming the Rio Tapajos in the Amazon Basin. The new taxon is distinguished from its congeners by a unique color pattern, whose most striking features are: two elliptical white spots, anterior to nostrils; predorsal region darkly pigmented with five unpigmented spots arranged as anteriorly pointed chevron; and a rostrocaudally elongate cross along most of the caudal peduncle. The placement of the new species in Hisonotus as well as its possible affinities within that genus are discussed in light of the current knowledge of the phylogenetic relationships among the Hypoptopomatinae.

A New Diminutive Species of Loricaria (Siluriformes: Loricariidae) from the Rio Paraguay System, Mato Grosso do Sul, Brazil

Loricaria coximensis. new species, is described from the Rio Paraguay basin, in Mato Grosso do Sul State, Brazil. It is distinguished from all other species of Loricaria, except L. holmbergi, L. lundbergi, L. parnahybae, and L. pumila by having abdominal plates confined to the pre-anal shield and posterior median abdominal area, usually loosely joined or separated by naked areas, pectoral girdle mostly naked, with isolated plates near base of pectoral fins and posterior to gill opening vs. abdominal plates well developed and tightly arranged across the entire median abdominal area, including the pectoral girdle. It is distinguished from these other four species by meristic counts and several morphometric proportions, particularly a broader head (19.4-21.3% SL vs. 14.1-19.1% SL). Loricaria coximensis becomes the third described paedomorphic species of Loricaria, along with L. nickeriensis and L. pumila, based on its small adult size (<100 mm SL), reduced number of lateral dermal plates, and incomplete abdominal plate development. The new species is presently known only from a limited section of the Rio Coxim, which has been severely impacted by a hydroelectric dam and widespread conversion of land for agriculture.

A new armored catfish species of the genus Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae) from the upper rio Xingu basin, Brazil

A new armored catfish species of the genus Hypostomus is described from the upper rio Xingu basin, Mato Grosso State, Brazil. The new species is diagnosed from congeners by having high number of teeth (58 to 101, mean 77 on premaxilla, and 58 to 105, mean 80 on dentary), dark spots over body and fins, and abdomen mostly naked. The new species is known from the rapids of the rio Culuene, where it is sympatric with Hypostomus faveolus.

The cascudos of the genus Hypostomus Lacépède (Ostariophysi: Loricariidae) from the rio Iguaçu basin

We reviewed several large collections of the genus Hypostomus from the rio Iguaçu basin summing up to 793 specimens mainly from the Laboratório de Ictiologia do Departamento de Ecologia e Biologia Evolutiva from Universidade Federal de São Carlos, from fish collection of Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura da Universidade Estadual de Maringá, and from the Museu de História Natural do Capão da Imbuia. Hypostomus albopunctatus, H. commersoni, H. derbyi, and H. myersi are redescribed and Hypostomus nigropunctatus is described as a new species. A practical key for identification of Hypostomus species from the rio Iguaçu is also provided.

New species of Harttia (Loricariidae, Loricariinae) from the Rio Sao Francisco Basin

A new species of the mailed catfish genus Harttia is described from the Sao Francisco River drainage, States of Minas Gerais and Bahia, Brazil. The new species is distinguished from congeners by the combination of an abdominal region covered by small bony plates; plates 3-4 times in eye diameter; interorbital width 3.1-4.0 in head length and greater than eye diameter; body width at anal fin origin 6.3-8.3 in standard length; margins of the head and pectoral fin spine of mature males with elongate and conspicuous odontodes; anal fin of males longer than of females. A key to Harttia species and a comparison with other species are provided.

Composição elementar corporal, desbalanço alimentar e reciclagem de nutrientes em peixes de um riacho costeiro de Mata Atlântica

No presente estudo foi avaliada a variação na dieta e na composição elementar corporal (C:N:P) de oito espécies de peixes que coocorrem em dois trechos de um riacho. Além disso, foram investigadas as diferenças na demanda e excreção de nutrientes por duas espécies de Loricariidae, sendo uma nativa (Hypostomus punctatus) e a outra não nativa (Parotocinclus maculicauda). As coletas foram realizadas no rio Ubatiba, através de pesca elétrica em diferentes meses entre os anos de 2010 e 2012. A partir da análise alimentar, observamos que as espécies apresentaram variação na dieta entre as localidades, com exceção das duas espécies de Characidium. Apesar destas variações, o presente estudo corroborou a hipótese de homeostase estequiométrica corporal. A exceção foi a espécie Hoplias malabaricus que apresentou variação na concentração elementar corporal e alto desbalanço alimentar entre as localidades, sendo as diferenças mais acentuadas na área aberta. Analisando as diferenças na demanda nutricional dos Loricariidae verificamos uma maior concentração corporal de carbono e nitrogênio para a espécie nativa e maior de fósforo na espécie não nativa, sendo essa diferença confirmada por um maior consumo de fósforo pela espécie não nativa. A análise da excreção revelou que a espécie nativa excreta mais nitrogênio e fósforo que a não nativa. Sendo assim, os resultados sugerem que a espécie não nativa apresenta uma requisição de fósforo maior do que a nativa. Logo, ambientes com altas concentrações de nutrientes, tal como o riacho estudado, podem favorecer o estabelecimento desta espécie

Biologia alimentar da taxocenose de peixes do Rio Silveira (cabeceira do Rio Pelotas), São José dos Ausentes, Rio Grande do Sul, Brasil

A região de São José dos Ausentes (planalto sul-riograndense), onde se situa o rio Silveira pertencente a cabeceira do rio Pelotas (bacia do rio Uruguai), caracteriza-se por uma ictiofauna composta de espécies endêmicas e várias espécies novas ainda não descritas. O conhecimento referente a estrutura trófica da ictiofauna desta região ainda é inexistente, motivo pelo qual este trabalho teve com objetivo caracterizar a biologia alimentar das espécies de peixes encontradas no rio Silveira. O período de amostragem iniciou em julho de 2000 e concluiu-se em julho 2001. Os indivíduos foram capturados mensalmente através de redes de espera (malhas 1,5 cm entrenós) e puçás, em ambientes de corredeiras e remansos. Foram encontradas seis espécies de peixes neste trecho do rio Silveira: Astyanax sp. n. 4 (Characidae), Eurycheilichthys pantherinus (Loricariidae), Hemipsilichthys sp. n. I (Loricariidae), Cichlasoma facetum (Cichlidae), Rhamdia sp. (Pimelodidae) e Bryconamericus sp. n. 1 (Characidae). O conteúdo estomacal foi identificado para cada uma destas espécies, sendo somente analisado através do método de freqüência de ocorrência, composição percentual e pelo cálculo do índice de importância alimentar para as três espécies mais freqüentes e abundantes. Dentre os itens encontrados destacam-se para Astyanax sp. n. 4 matéria vegetal e Ephemeroptera; para Eurycheilichthys pantherinus larvas de Diptera Simulidae e Ephemeroptera; e em Hemipsilichthys sp. n. I detritos, onde se verificou a presença de diatomáceas e clorofítas. O cálculo do coeficiente de sobreposição alimentar não apresentou valor significativo para estas três espécies. As demais espécies apresentaram os seguintes itens em sua dieta, Cichlasoma facetum larvas de Tricoptera, Ephemeroptera, Gastropoda e insetos alóctones; Rhamdia sp. escamas, Gastropoda, larvas de Lepidoptera, Tricoptera, Ephemeroptera, sementes, matéria vegetal, sedimento; e Bryconamericus sp. n. 1 larvas de Diptera (Simulidae, Psychodidae, Chironomidae), larvas de Tricoptera, Ephemeroptera, Diatomáceas, Clorofítas, Diptera adulto, Hymenoptera, Coleoptera. Esta dieta sugere os seguintes hábitos alimentares para Astyanax sp. n. 4 onívoro, Eurycheilichthys pantherinus insetívoro, Hemipsilichthys sp. n. I detritívoro, Cichlasoma facetum insetívoro, Rhamdia sp. onívoro, e Bryconamericus sp. n. 1 insetívoro.

Diversidade Ictiofaunística e Ecologia reprodutiva de uma espécie nativa de peixe da Bacia Piranhas-Assu, RN

The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning

Effects of the spermatozoa: oocyte ratio, water volume and water temperature on artificial fertilization and sperm activation of cascudo-preto

The objective of this study was to evaluate the effects of water volume and water temperature on the sperm motility duration and the number of spermatozoa, and the water volume on the fertilization rates of oocytes of Rhinelepis aspera. Experiments were carried out to evaluate the effect of semen dilutions (1.74×10-5, 1.74×10-4, 1.74×10-3, 1.74×10-2, 1.74×10-1 and 1.00 mL of sperm.mL-1 of water) and water temperature (5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 ºC) on spermatozoa motility duration. In addition, the effects of insemination dose (7×10³, 7×10(4), 7×10(5), 7×10(6) and 7×10(7) spermatozoa.oocyte-1) and water volume (1.0, 30.0, 60.0, 90.0 and 120.0 mL water.2.0 mL-1 oocytes) on the artificial fertilization rates of oocytes were evaluated. The longest sperm motility duration were observed for the semen dilution of 1.74×10-5 mL semen.mL-1 water and in water at 5 ºC. The highest fertilization rates were obtained for insemination doses between 7.00×10³ and 1.23×10(7) spermatozoa. oocyte-1 and water volume of 28.11 mL water.2.0 mL-1 oocytes.

Molecular phylogeny of the armored catfish family Callichthyidae (Ostariophysi, Siluriformes)

The family Callichthyidae comprises eight genera of fishes widely distributed across the Neotropical region. In the present study, sequences of the mitochondrial genes 12S rRNA, 16S rRNA, ND4, tRNA(His), and tRNA(Scr) were obtained from 28 callichthyid specimens. The sample included 12 species of Corydoras, three species of Aspidoras, two species of Brochis, Dianema, Lepthoplosternum, and Megalechis, and two local populations of Callichthys and Hoplosternum. Sequences of Nematogenys inermis (Nematogenyidae), Trichomycterus areolatus, and Henonemus punctatus (Trichomycteridae), Astroblepus sp. (Astroblepidae), and Neopleeostomus paranensis, Delturus parahybae, and Hemipsilichthys nimius (Loricariidae) were included as the outgroup. Phylogenetic analyses were performed by using the methods of maximum parsimony and maximum likelihood. The results of almost all analyses were very similar. The family Callichthyidae is monophyletic and comprises two natural groups: the subfamilies Corydoradinae (Aspidoras, Brochis, and Corydoras) and Callichthyinae (Callichthys, Dianema, Hoplosternum, Lepthoplosternum, and Megalechis), as previously demonstrated by morphological studies. The relationships observed within these subfamilies are in several ways different from those previously proposed on the basis of morphological data. Molecular results were compared with the morphologic and cytogenetic data available on the family. (C) 2003 Elsevier B.V. All rights reserved.

Description of a new species of Pareiorhina (Siluriformes: Neoplecostominae) from Rio Sao Francisco basin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The fish zonation of the Itanha,m river basin in the Atlantic Forest of southeast Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)