Julio Cesar Garavello

Revision of genus Steindachneridion Eigenmann & Eigenmann, 1919 (Ostariophysi, Siluriformes, Pimelodidae)

After several years collecting in the type-localities and studying representative samples of genus Steindachneridion Eigenmann & Eigenmann, 1919 from Brazilian and foreign museums, a taxonomic revision of the Recent species of the genus is presented, including the description of a new species from the rio Iguacu, above the great falls. Steindachneridion species are large sized fishes, reaching 1000 mm total length or more, and sharing some anatomical characters that, at least tentatively, support the monophyly of the genus. In addition to the general features found in the Pimelodidae, the species S. amblyurum (Eigenmann & Eigenmann, 1888), S. parahybae (Steindachner, 1877), S. doceanum (Eigenmann & Eigenmann, 1889), S. scriptum (Miranda Ribeiro, 1918), S. punctatum (Miranda Ribeiro, 1918), and S. melanodermatum, new species, share the shape of the vomer tooth plates, six to eight branched rays in the dorsal-fin, and a low number of gill-rakers. All species, except fossil ones, are redescribed and a key for their identification is provided.

Fish assemblage composition in a tributary of the Mogi Guaçu river basin, southeastern Brazil

Fish assemblage composition and seasonal patterns of species abundance were studied in Cabaceiras stream, a tributary of the Mogi Guacu river in Sao Paulo State, Brazil. Three stations were sampled monthly from June 1999 to May 2000 using sieves and small trawl net and gill nets. Fifteen fish families, 37 genera and 45 species were captured. Characiformes (27 spp.) and Siluriformes (13 spp.) were the most species-rich orders. Gymnotiformes and Perciformes were represented by two species each, and Synbranchiformes had only a single species. One group of species (approximately 75 %) persisted in the stream throughout the year. A second group (approximately 25 %) contained species that only occupy the stream for a limited period of their life cycle, and overall fish assemblage composition was associated with the seasonal flood cycle.

Ictiofauna do Ribeirão do Pântano, afluente do Rio Mogi-Guaçu, Bacia do Alto Rio Paraná, São Paulo, Brasil

The fish assemblages from Pântano stream were studied monthly from May 2000 to June 2001 and the composition, longitudinal distribution and constancy of fish species are described. Samples were performed in three different sites, using gill nets, sieves, cast net and trawl net. Sixty-three species of 46 genera, pertaining to 18 families were identified. Characiformes with 30 species (47.62%) and Siluriformes with 22 (34.92%) were the more specious orders. Five species of Perciformes, three species of Gymnotiformes, two species of Cyprinodontiformes, and only a single Synbranchiformes species were registered.

Platydoras brachylecis, a new species of thorny catfish (Siluriformes: Doradidae) from northeastern Brazil

Platydoras brachylecis, new species, is described from coastal drainages of northeastern Brazil (Pindare to Parnaiba rivers), and diagnosed from congeners by the unique combination of: pale yellow to white stripe beginning above orbits, continuing midlaterally on body and onto middle rays of caudal fin; skin in axil of each midlateral thorn without concentration of pigment forming small dark spot, midlateral scutes shallow (depth of 10 th scute 8.8-11.9% of SL), and midlateral scutes on caudal peduncle distinctly separated by strip of skin from middorsal and midventral caudal-peduncle plates. Three additional species of Platydoras are recognized as valid: P. armatulus (lower Orinoco, Amazon and Paraguay-Parana drainages), P. costatus (coastal drainages of Suriname and French Guiana), and P. hancockii (upper Orinoco, Negro, Essequibo and Demerara drainages). The nominal species P. dentatus and P. helicophilus are tentatively treated as junior synonyms of P. costatus. A key to species of Platydoras is provided. Platydoras brachylecis, especie nova, e descrita para as drenagens costeiras do nordeste do Brasil (rios Pindare a Parnaiba) e diagnosticada de suas congeneres pela exclusiva combinacao dos seguintes caracteres: faixa amarelo-palida a branco iniciando acima das orbitas, continuando medio-lateralmente sobre o corpo e atingindo os raios medianos da nadadeira caudal; pele das axilas dos espinhos medio-laterais sem concentracao de pequenas pintas negras; escudos medio-laterais baixos (altura do decimo escudo 8.8-11.9% do comprimento padrao) e escudos medio-laterais do pedunculo caudal distintamente separados das placas medio-dorsais e medio-ventrais da mesma regiao por uma faixa de pele. Mais tres especies de Platydoras sao reconhecidas como validas: P. armatulus (distribuida pelas drenagens do baixo Orinoco, Amazonia e Paraguai-Parana), P. costatus (drenagens costeiras do Suriname e Guiana Francesa) e P. hancockii (drenagens do Negro, Essequibo, Demerara e alto Orinoco). As especies nominais P. dentatus e P. helicophilus sao provisoriamente consideradas sinonimos juniores de P. costatus. Uma chave de identificacao para as especies do genero Platydoras e apresentada.

Hisonotus insperatus: New Species, from the Upper Rio Paraná Basin (Pisces: Ostariophysi: Loricariidae)

Abstract Hisonotus insperatus, new species, is distinguished from all the other species of the genus Hisonotus Eigenmann and Eigenmann by the combination of a pair of rostral plates at the tip of the snout, the complete median plate series to base of the caudal fin, a lateral line that is continuous along the middle of the body, a pectoral spine smooth and lacking odontodes along its posterior dorsal margin for a distance more than one-half of its width, and a scapular bridge that is completely exposed, sometimes with a very reduced median pair of arrector fossae.

Composição da ictiofauna do rio Quilombo, tributário do rio Mogi-Guaçu, bacia do alto rio Paraná, sudeste do Brasil

A study about fish composition in the Quilombo river, of the upper Parana hydrographic system, is presented. We aimed to identify which species inhabit this small river, to verify the frequency they occur and to study the longitudinal distribution of the ichthyofauna. Fish were sampled for a period of one year and ten months (September 2003 to June 2005) at four collection sites defined through the river basin, comprising dry and wet seasonal periods. Trawlnet, gillnets, seine net, sieves and hooks were used for fish sample. Fish collected were immediately fixed in 10% formalin solution. In the laboratory specimens were preserved in ethanol 70%, identified and deposited in the fish collection of the Laboratorio de Ictiologia Sistematica (LISDEBE) of the Departamento de Ecologia e Biologia Evolutiva of the Universidade Federal de Sao Carlos. An amount of 2982 specimens belonging to 6 orders, 19 families, 52 genera and 68 species were collected. The orders Characiformes (57.3%) and Siluriformes (30.9%) predominated in terms of species richness. The orders Gymnotiformes, Cyprinodontiformes, Perciformes and Synbranchiformes summed 11.8% of total fish richness. The analysis of constancy revealed that the ichthyofaunistic composition in the middle and lower sampled stretches suffered higher temporal variability in comparison to upper stretches of Quilombo river basin. The similarity (Jaccard index) among samples showed that each collection site have distinct assemblages of fish.

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 Iguacu basin summing up to 793 specimens mainly from the Laboratorio de Ictiologia do Departamento de Ecologia e Biologia Evolutiva from Universidade Federal de Sao Carlos, from fish collection of Nucleo de Pesquisas em Limnologia, Ictiologia e Aquicultura da Universidade Estadual de Maringa, and from the Museu de Historia Natural do Capao 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 Iguacu is also provided.

A new species of the genus Pimelodus La Cépède, 1803 from the rio Iguaçu basin and a reappraisal of Pimelodus ortmanni Haseman, 1911 from the rio Paraná system, Brazil (Ostariophysi: Siluriformes: Pimelodidae)

A new species, Pimelodus britskii, is described from the rio Iguacu in the rio Parana drainage, on the border of Parana and Santa Catarina states, Brazil. Specimens of this species were wrongly included in the type series of Pimelodus ortmanni. Pimelodus britskii is distinguished from its congeners by color pattern, having circular dark brown blotches usually smaller than one orbital diameter, regularly and scattered along the trunk. Differs from P. ortmanni by the following characters: body depth at posterior cleithral process greater than head length; lips not prominent; and maxillary barbel reaching or surpassing vertical drawn through median of adipose fin. Pimelodus britskii represents the second species of the genus Pimelodus from the rio Iguacu basin.

A cytochemical, light and electron microscopic study of the peripheral blood leucocytes of hybrid surubim catfish (Pseudoplatystoma corruscans x Pseudoplatystoma fasciatum)

This paper describes the results of our initial studies with hybrid surubim catfish leucocytes and suggests that the techniques used may have further application. According to size, shape, staining patterns and ultrastructure, five blood leucocyte types were identified in the peripheral blood of surubim: lymphocytes, thrombocytes, monocytes, neutrophils and eosinophils. A tentative plasma cell was also observed by electron microscopy. Haematocrit and leucocrit were also analysed and reference values for these parameters are proposed. The results obtained in the present study should be useful to support further evaluations, and to develop or refine methods to properly evaluate the health status of this fish.

Geographic variation in Leporinus friderici (Bloch) (Pisces: Ostariophysi: Anostomidae) from the Paraná‐Paraguay and Amazon River basins

Morphological variation among populations of Leporinus friderici (Bloch), an anostomid fish of widespread neotropical distribution, has been hypothesized but never conclusively demonstrated. We used multivariate procedures to examine patterns of morphometric variation among populations of L. friderici from three South American biogeographic regions: the Paraná‐Paraguay River and Amazon River basins of Brazil, and the Marowijne River basin of Suriname. Samples from the southern Paraná‐Paraguay basin are completely distinct from the northern Amazonian and Suriname regions in principal components analysis, primarily on the basis of body elongation and orbit differcnces. Samples from the two northern regions were separated in a size‐free canonical variates analysis by differences in relative body depth. These results emphasize a need for further studies of neotropical fish species with similar distribution patterns.