Palpimanid spiders from Guyana: new species of the genera Fernandezina and Otiothops (Araneae, Palpimanidae, Otiothopinae)

Two new species of the spider family Palpimanidae from Guyana are described: Fernandezina takutu, the first species of this genus known from this country andOtiothops giralunas, that seems to be the sister species of O. goloboffi Grismado, 1996 from northwestern Argentina.

Tetraploidía en Ceratophrys (Anura, Leptodactylidae), análisis del registro fósil

It has been confirmed the existence of the tetraploid counterpart of the genus Ceratophrys Wied, 1824 (extint at the present time) in Argentina and Brazil since the Pliocene, and the apparition of the octaploidy in the Upper Pleistocene - Holocene. Fossil material of the diploid form, distinctive of the Chacoan District, has been reported from the horizons of the Montehermosense Formation in south-east of the province of Buenos Aires, Argentina. The coexistence of diploid-tetraploid and tetraploid-octaploid forms in the same province was documented.

Revisão taxonômica do gênero Homodiaetus (Teleostei, Siluriformes, Trichomycteridae)

The genus Homodiaetus Eigenmann & Ward, 1907 is revised and four species are recognized. Its distribution is restricted to southeastern South America, from Uruguay to Paraguay river at west to the coastal drainages of Rio de Janeiro State, Brazil. Homodiaetus is currently distinguished from other genus of Stegophilinae by the combination of the following characters: origin of ventral-fin at midlength between the snout tip and the caudal-fin origin; opercle with three or more odontodes; and gill membranes confluent with the istmus. Homodiaetus anisitsi Eigenmann & Ward, 1907, is diagnosed by the caudal-fin with black middle rays, margin of upper and lower procurrent caudal-fin rays with dark stripes extending to the caudal-fin, and 3-6 opercular odontodes; H. passarellii (Ribeiro, 1944) with 6-7 opercular odontodes, 21-24 lower procurrent caudal-fin rays and 23-26 upper procurrent caudal-fin rays; H. banguela sp. nov. with 9 opercular odontodes, 17-19 lower procurrent caudal-fin rays, 17-22 upper procurrent caudal-fin rays, reduction of fourth pharyngobranchial with only three teeth and untoothed fifth ceratobranchial; and H. graciosa sp. nov. with 5-6 dentary rows, 7-9 opercular odontodes and 16-23 upper procurrent caudal-fin rays.

Efectos del herbicida Paraquat sobre el zooplancton

The effects of 0.1; 0.2; 0.4 and 0.8 mlPQ/L were analized on a zooplankton community, to determine the most sensitive species and to analize the occurence of physical abnormalities. A total of 40 taxa were determined. Paraquat affected significantly the zooplankton density but not the species richness. A progressive state of deformation of these organisms was also observed. Paraquat showed to be highly toxic for the zooplankton, so this herbicide should be strictly regulated in aquatic and terrestrial ecosystems.

Novas espécies de Trichomyia (Diptera, Psychodidae) da Mata Atlântica da Bahia, nordeste do Brasil

Six new species of Trichomyia from Atlantic rain forest of Bahia, northeastern Brazil, are described: T. itabunensis, T. onorei, T. queirozi, T. silvatica, T. sulbaianensis and T. teimosensis. The first two have palpi with four segments, similar to the other Neotropical species. The other four species have palpi with three segments, similar to other species with wide world distribution.

Ecologia da ictiofauna de um córrego de cabeceira da bacia do alto rio Paraná, Brasil

Ecological studies were conducted in the ichthyofauna of Cedro, a small headwater stream located in a degraded area of State of São Paulo, Brazil, situated in the upper Paraná River basin. These are the results of two non-consecutive years observations and collections in two biotopes of that stream: a pool and a rapid. The ecological characteristics studied change in space and time. The present richness of species is high (21 species), nine of which are constant, six accessory and six accidental. The diversity is low (0.69 to 2.38), and the numeric predominance, from one to three species, occurred in both biotopes. The most frequent species are Poecilia reticulata (Peters, 1859) (28.1%), Corydoras cf. aeneus (Gill, 1858) (20.3%) and Hypostomus cf. ancistroides (Ihering, 1911) (19.8%). The density ranges from 0.7 to 19.8 specimens/m³. The similarity index indicates high similarity between the ichthyofauna (45.0% to 95.0%) inside the same or contiguous biotopes. The evenness (0.46 to 1.0) is comparable to those found in similar studies carried out in other streams.

Fator de condição gonadal, índice hepatossomático e recrutamento como indicadores do período de reprodução de Loricariichthys platymetopon (Osteichthyes, Loricariidae), bacia do rio Uruguai médio, sul do Brasil

The recruitment period of Locariichthys platymetopon (Isbrucker & Nijssen, 1979) was investigated. It has been found out, through the data analysis, that the gonadal condition factor is a good indicator of the reproductive period and that the hepatossomatic index is probably related to the storage of reservation for the winter period. The recruitment occurred in November coinciding with the reproductive activity of May.

Catelanus and Fusimorphus (Coleoptera, Elateridae, Agrypninae)

The historical review and the diagnosis for the monotypical genera Catelanus Fleutiaux, 1942 and Fusimorphus Fleutiaux, 1942 are presented. Catelanus trilineatus (Castelnau, 1836) and Fusimorphus submetallicus (Fleutiaux, 1924) are redescribed and illustrated and new diagnostic characters are raised up. The historical review and the discussion on the remainder Neotropical genera of Hemirhipini are also included.

Comportamento alimentar de aves em Miconia rubiginosa (Melastomataceae) em fragmento de Cerrado, São Paulo

Birds of 11 species were observed feeding on fruits of Miconia rubiginosa (Bonpl.)DL between February and March 1985 in Itirapina cerrado, State of São Paulo, Brazil. The feeding strategies of birds with regards to fruit use, and the role of the fruits as food resources for the birds in cerrado are analyzed.

Uma espécie nova de Schwarzula da Amazônia (Hymenoptera, Apidae, Meliponini)

Schwarzula coccidophila sp. nov., a tiny Amazonian stingless bee, that attends scale insects (Cryptostigma Ferris, 1922, Coccidae) in its nest, is described. It is distinguished from Schwarzula timida (Silvestri, 1902), the only other species of the genus, mainly by the malar area longer than diameter of 3rd flagellomere, and the denser plumose pilosity. Additional records of S. timida is presented.

Growth, molt and survival of Palaemonetes argentinus (Decapoda, Caridea) under different light-dark conditions

Growth, survival and molting rate in Palaemonetes argentinus Nobili, 1901 were compared under different light-dark conditions. During 80 days, 150 immatures of both sexes (initial mean weight 0.09±0.002g), from Los Padres lagoon, Mar del Plata, Argentina, were maintained in aquaria at 19±0.4°C under three light conditions: 0:24, 10:14 and 13:11 (L-D). They were fed daily on an artificial diet (45% proteins, 17.2% lipids, 7% water, 7% ash). Good weight increment was obtained with the three treatments, finding a positive linear correlation between mean weight and time (0:24, r=0.97; 10:14, r=0.99; 13:11, r=0.98). There were no significant differences in the percentage increment in mean weight among the treatments (0:24, 19.3%; 10:14, 29.3% and 13:11, 26.5%) (p<0.05). Molting rate was significantly higher at a long-day photoperiod (MR=1.7) than at a short-day (MR=0.6) or continuous dark condition (MR=0.3) (p<0.05). The lowest survival was found in animals maintained under 13:11 L-D conditions (77%), being statistically different of the other two treatments (92% and 89% at 10:14 and 0:24, respectively) (p<0.05). These results suggest that the best growth and survival in P. argentinus result with a 10:14 L-D cycle, and that the growth is less affected by photoperiod than molting rate and survival.

Spongia (Heterofibria) catarinensis sp. nov. (Porifera, Spongiidae) no litoral de Santa Catarina, Brasil

Uma nova espécie, Spongia (Heterofibria) catarinensis, é descrita para a Ilha das Aranhas (27º29'077''S, 48º21'380''W), Estado de Santa Catarina, Brasil. Difere das outras espécies do gênero do Atlântico sudoeste pela morfologia externa e arquitetura. A nova espécie é caracterizada por apresentar forma massiva, incrustante com projeções lobulares; fibras primárias medindo 60-100 µm; fibras secundárias 11,5-69 µm; fibras pseudoterciárias 2,3-23 µm e distância entre fibras primárias 391-920 µm; distância entre fibras secundárias/pseudoterciárias 92-575 µm; fibras secundárias/pseudoterciárias constituindo malhas poligonais com 30-700 µm de diâmetro. A espécie pertence ao subgênero Heterofibria Cook & Bergquist, 2001 por apresentar uma clara dicotomia de suas fibras.

Crescimento de Chasmagnathus granulatus (Crustacea, Decapoda, Varunidae) na Lagoa do Peixe, Rio Grande do Sul, Brasil

O estudo do crescimento em largura da carapaça de Chasmagnathus granulatus Dana, 1851 foi baseado em dados de 1940 exemplares coletados na Lagoa do Peixe, Estado do Rio Grande do Sul, Brasil. As coletas foram realizadas de julho/1994 a junho/1995. Os caranguejos foram coletados manualmente nas margens da lagoa e em laboratório foram separados por sexo e a largura da carapaça mensurada. O modelo de von Bertalanffy foi utilizado para a descrição do crescimento. As curvas de crescimento em largura (mm), para dados obtidos através da progressão modal, são descritas pelas equações: Lt= 44,69 [1- e -0.0066(t+20,45)] e Lt= 37,63 [1- e -0.0072(t+21,92)], resultando em idades máximas estimadas de 2 anos para ambos os sexos.

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

As assembléias de peixes do ribeirão do Pântano, São Paulo, Brasil foram estudadas mensalmente entre os meses de maio de 2000 e junho de 2001. Estudos sobre sua composição, distribuição longitudinal e constância das espécies de peixes foram realizados. Foram feitas coletas da ictiofauna com auxilio de redes de espera, peneiras, tarrafas e redes de arrasto em três diferentes pontos do ribeirão. Sessenta e três espécies pertencentes a 46 gêneros de 18 famílias foram identificadas. As ordens Characiformes (com 30 espécies registradas, representando 47,62% da ictiofauna) e Siluriformes com 22 espécies, (34,92% do total), foram as ordens melhor representadas no elenco das espécies do ribeirão do Pântano. Cinco espécies pertencentes a ordem Perciformes, três a ordem Gymnotiformes, duas a Cyprinondontiformes e uma de Synbranchiformes também foram encontradas.

Reproductive traits of Gymnogeophagus labiatus (Teleostei, Cichlidae), in an upper stretch of Sinos river, Caraá, Brazil

This work describes the reproduction of Gymnogeophagus labiatus (Hensel, 1870) from an upper stretch of Sinos river, southern Brazil, based on the analysis of 174 males and 132 females captured in monthly samples taken from January to December 2007. Results showed that reproductive activity occur in spring and summer although ripe males were found along the year. The standard length of the smallest ripe male was 104.74 mm (Lt) and the smallest ripe female was 55.00 mm (Lt). There was a significant difference in total sex ratio, with 1.32 males to each female (χ2 = 5.76). Males were much more abundant in March (1.75 males: 1 female) and December (5 males: 1 female). Females were more abundant in the 62├77 mm interval (1 male: 2.36 female) while males were more abundant in the 77├92 mm size interval (2.57 males: 1 female). The largest length intervals were composed of only males. Mean absolute fecundity was 113.4 (± 31.24 sd) and mean relative fecundity was 0.0125 (± 0.0026 sd) oocytes/mg. In ripe ovaries, small-diameter oocytes were observed at high frequencies while larger ones occurred at lower frequencies. This pattern is common in fishes with asynchronous oocyte development. Characteristics of G. labiatus, such as low fecundity, asynchrony in oocyte development, multiple spawning, and its well-known parental care behavior, are consistent with an equilibrium strategy, as proposed for other cichlids.