A new species of Leptophoxoides Barnard, 1962 (Amphipoda, Phoxocephalidae) from the Brazilian northeastern continental slope

A new species of Leptophoxoides Barnard, 1962 is described with material from the continental slope of Rio Grande do Norte state, northeastern Brazil at three different depths: 150, 400 and 2,500 meters. Leptophoxoides longisetae sp. nov. can be diagnosed and distinguished from the other two species of the genus, L. molaris Barnard, 1962 and L. marina Senna, 2010, by the following characters: antenna 1 peduncular article 1 ventral apex weakly ensiform; maxilla 1 inner plate longer than outer; maxilliped palp article 3 with blunt and extremely protuberant apex; gnathopods 1-2 carpus almost cryptic; gnathopod 2 palm defined by a large and sharply produced palmar hump; pereopod 6 basis posterodistal corner produced as a blunt lobe; and telson with two dorsal long plumose setae on each side. This is the first record of the genus for northeastern Brazilian waters, uncovering a higher biodiversity in deep waters.(AU)

A new species and record of Biancolina Della Valle, 1893 (Amphipoda, Senticaudata, Ampithoidae) from the Southwestern Atlantic

Here we describe a new species of Biancolina from Pernambuco, Brazil, found in association with the brown algae Sargassum spp., between 0.5 and 1.0 m depth. The new species differs from its congeners mainly by the following combination of characters: antenna 1 twice the length of antenna 2, lacinia mobilis present in both mandibles, article 4 of the maxilliped bulbose; coxa 6 with anteroventral lobe well developed as in posteroventral lobe, peduncle of uropod 1 weakly setose, palm of pereopods 5-7 lacking robust seta. This is the first record of Biancolina from the southwestern Atlantic.(AU)

First record and a new species of Foxiphalus Barnard, 1979 (Crustacea: Amphipoda: Phoxocephalidae) from the Atlantic Ocean, with two new records of the family from northeastern Brazil

A new species of Foxiphalus Barnard, 1979 is described. The material examined was collected as part of the project "Avaliação da biota bentônica e planctônica da Bacia Potiguar e Ceará" (BPOT), off northeastern Brazilian continental slope on the state of Rio Grande do Norte at depths ranging from 135 to 283 meters. Foxiphalus potiguara sp. nov. is recognized among its congeners by: rostrum slightly exceeding the article 2 of antenna 1; lower lip outer lobes with strong shoulder cusps; maxilliped inner plate with two apical robust setae; gnathopod 2 carpus shortened; pereopod 5 basis tapering distally; and epimeral plate 3 posterior margin weakly crenulated. This is the first record of Foxiphalus for the Atlantic Ocean and we provide an amended diagnosis of the genus and an identification key to its world species. In addition, two new records of Phoxocephalidae are reported from northeastern Brazil: Heterophoxus shoemakeri Andrade & Senna, 2020 and Metharpinia dentiurosoma Alonso de Pina, 2003.

Estrutura populacional de Talitroides topitotum (Crustacea: Amphipoda: Talitridae) em Santa Maria, região central do Rio Grande do Sul, Brasil / Population structure of Talitroides topitotum (Crustacea: Amphipoda: Talitridae) from Santa Maria, central region of Rio Grande do Sul State, Brazil

Tallitroides topitotum (Burt, 1934) (Talitridae) is one of the representatives of Amphipoda that has adapted to terrestrial environment. This research aimed to describe the population structure of this talitrid in the morphometric and reproductive aspects. The study was carried out in the central region of Rio Grande do Sul, Brazil, from June 2020 to May 2021. The talitrids were monthly collected with pitfalls exposed for 48 hours and they were sexed, photographed, and measured (body length, cephalic length, and marsupium length ­ in millimeters). Ovigerous females had their eggs counted and measured. In addition, we correlated the size data and the sampling latitudes of T. topitotum from previous and present studies. A total of 492 individuals were collected, from which 62 were ovigerous females, 188 non-ovigerous females, and 242 juveniles. No male was sampled. There was a significant correlation between body and head lengths and body and marsupium lengths in ovigerous females. We found no correlation between morphometric data and female fertility. Although not significant, there was a positive correlation between the size of talitrids and the latitude of occurrence. Body size can be inferred from head size, and marsupium size from body size, as both are strongly correlated. The absence of relationship between body size and fecundity may be related to environmental factors that can affect the talitrid reproduction. A clear relationship between the mean body size of T. topitotum and the latitude of their occurrence can be obtained with more studies conducted with a large sampling.

Talitroides topitotum (Burt, 1934) (Talitridae) é um dos representantes de Amphipoda que se adaptaram ao ambiente terrestre. O objetivo desta pesquisa foi avaliar a estrutura populacional deste talitrídeo e correlacionar entre si dados morfométricos e aspectos reprodutivos da população. O estudo foi realizado na região central do Rio Grande do Sul, Brasil, entre junho de 2020 e maio de 2021. Para tal, foram coletados mensalmente espécimes com o auxílio de armadilhas de queda (pitfalls), que ficaram expostos durante 48 horas no campo. Os animais foram sexados, fotografados e medidos (comprimento corporal, comprimento cefálico e comprimento do marsúpio ­ em milímetros). As fêmeas ovígeras tiveram todos os seus ovos contados e medidos. Além disso, foram comparados os tamanhos máximos e latitudes de estudos populacionais realizados com a espécie. No total foram coletados 492 indivíduos, dos quais 62 eram fêmeas ovígeras, 188 não-ovígeras e 242 juvenis. Nenhum macho foi amostrado. Houve correlação significativa entre o comprimento corporal e cefálico e o comprimento corporal e de marsúpio nas fêmeas ovígeras. Não houve correlação entre os dados morfométricos e a fecundidade das fêmeas. Na análise de correlação entre tamanho dos talitrídeos e latitude houve correlação positiva, embora não significativa. O tamanho corporal pode ser inferido a partir do tamanho cefálico, bem como o do marsúpio a partir do corporal, pois ambos estão fortemente correlacionados. O fato de não haver relação entre tamanho e fecundidade pode estar relacionado a fatores ambientais, já que os mesmos podem afetar a reprodução do grupo. No que diz respeito à relação entre tamanho e latitude, mais estudos devem ser conduzidos com uma amostra maior, a fim de que seja verificada se a relação é significativa ou não.

A new species of Gammarus Fabricius, 1775 (Crustacea Amphipoda Gammaridae) from extreme high altitude Lake Tong Tso, Qinghai Tibetan Plateau

A new species of the genus Gammarus Fabricius, 1775 is described from Lake Tong Tso, an extreme high-altitude lake in the Qinghai-Tibetan Plateau. Gammarus pontualsp. nov. is considered part of the Gammarus lacustris G.O. Sars, 1863 group, which is characterized by having the inner ramus of uropod 3 longer than half the length of the outer ramus, and by having both rami covered with plumose setae. The new species stands apart from their congeners, mainly, by the following combination of characters: head with cephalic lateral lobe truncated; gnathopods 1-2 propodus weakly armed, with 1 stout seta defining palm; palm longer than posterior margin of propodus, with 1 main stout seta medially; pereopods 5-7 basis slender, posterior margin crenulate; epimeral plate 1 posterior margin produced into a short spine, facial ridge present; epimeral plates 2-3 posteroventral corner sharply pointed; uropod 3 rami covered with plumose setae, inner ramus about 80% the length of the outer ramus; telson apex with 2 stout setae on each side.(AU)

New and additional records of Metharpinia Schellenberg, 1931 and Microphoxus Barnard, 1960 (Crustacea: Amphipoda: Phoxocephalidae) from Brazilian waters

New records of the species Metharpinia dentiurosoma Alonso de Pina, 2003, M. grandirama Alonso de Pina, 2003, M. iado Alonso de Pina, 2003, Microphoxus cornutus (Schellenberg, 1931) and Mi. uroserratus Bustamante, 2002 are reported for Brazilian waters. A discussion about the Metharpinia-Microphoxus complex is presented based on literature review and new observations of sampled species. Emended diagnoses are presented for the recorded species of Metharpinia and identification keys to world species of Metharpinia and Microphoxus are provided.(AU)

New and additional records of Metharpinia Schellenberg, 1931 and Microphoxus Barnard, 1960 (Crustacea: Amphipoda: Phoxocephalidae) from Brazilian waters

New records of the species Metharpinia dentiurosoma Alonso de Pina, 2003, M. grandirama Alonso de Pina, 2003, M. iado Alonso de Pina, 2003, Microphoxus cornutus (Schellenberg, 1931) and Mi. uroserratus Bustamante, 2002 are reported for Brazilian waters. A discussion about the Metharpinia-Microphoxus complex is presented based on literature review and new observations of sampled species. Emended diagnoses are presented for the recorded species of Metharpinia and identification keys to world species of Metharpinia and Microphoxus are provided.

Crustacean communities in coastal ephemeral pools in the Araucanía region (38° S, Chile) / Comunidades de crustáceos em lagoas efêmeras costeiras na região de Araucanía (38° S, Chile)

The fauna communities of ephemeral pools in southern Chile are characterized by heterogeneity of crustacean taxa; nevertheless, no detailed studies exist of their community structure. The aim of the present study was to analyze the crustacean community structure in two groups of ephemeral pools (Puaucho and Nigue pools) in the coastal zone of the Araucanía region. A correlation matrix was made by species abundance against temperature, conductivity, pH and total dissolved solids. In a second step, a null model for species co-occurrence was applied to the total data and to each group. The results for total data revealed a significant direct relation between the abundance of H. costera, C. dubia and Mesocyclops. For the Puaucho pools, the same results were found together with direct associations with total dissolved solids, conductivity and pH. Finally, different results were found for the Nigue pools, with no clear significant associations, either direct or indirect, between the abundance of different crustacean taxa and abiotic parameters. These results were supported by the co-occurrence null model analysis, which revealed the presence of regulator factors for the total data, and for each of the two groups. Ecological topics are discussed with emphasis on meta-community dynamics.(AU)

As comunidades faunísticas das lagoas efêmeras do sul do Chile são caracterizadas pela heterogeneidade dos seus táxons. Entretanto, estudos detalhados da sua estrutura de comunidade ainda não existem. O objetivo do presente estudo foi analisar a estrutura da comunidade de crustáceos em dois grupos de lagoas efêmeras (Puaucho e Nigue) na zona costeira da região de Araucanía. A matriz de correlação foi feita com a abundância das espécies em função da temperatura, condutividade, pH e sólidos totais dissolvidos. Num segundo passo, um modelo nulo para as espécies de coocorrência foi aplicado aos dados totais e para cada grupo. Os resultados para os dados totais revelaram uma relação direta e significativa entre a abundância de H. costera, C. dubia e Mesocyclops. Para as lagoas Puaucho, os mesmos resultados foram encontrados, juntamente com associações diretas com sólidos totais dissolvidos, condutividade e pH. Finalmente, diferentes resultados foram encontrados para as lagoas Nigue, sem associações significativas claras, diretas ou indiretas entre a abundância de diferentes táxons de crustáceos e parâmetros abióticos. Estes resultados foram suportados pela análise de modelo de coocorrência nula, a qual revelou a presença de fatores reguladores para o total de dados, e para cada um dos dois grupos. Temas ecológicos são discutidos com ênfase na dinâmica de meta-comunidade.(AU)

Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.(AU)

La raya de círculos, Atlantoraja cyclophora , es una especie endémica del Atlántico Sudoccidental, que se distribuye desde Río de Janeiro, Brasil, hasta el norte de la Patagonia, Argentina. Los hábitos alimentarios de esta especie fueron evaluados frente a la costa de Uruguay y norte de Argentina, utilizando un enfoque de modelado de múltiples hipótesis. En general, la dieta estuvo compuesta principalmente por crustáceos decápodos (71,37 %IRI), seguido de peces teleósteos (28,54 %IRI). En menor proporción fueron consumidos moluscos, misidáceos, anfípodos, isópodos, anfioxos y elasmobranquios. El consumo de decápodos Natantia disminuyó con el incremento del tamaño del cuerpo de A. cyclophora . Por otro lado, el consumo de teleósteos se incrementó con el incremento del tamaño del cuerpo. Individuos maduros consumieron cangrejos en mayor proporción que individuos inmaduros. Los teleósteos fueron consumidos mayormente en la región sur (34º - 38ºS) y los cangrejos en la región norte (38º - 41ºS). Los decápodos Natantia fueron más consumidos en la estación cálida que en la estación fría. El tamaño de las presas consumidas se incrementó con el aumento del tamaño corporal de A. cyclophora , pero individuos de mayor tamaño no abandonadon el consumo de pequeños cangrejos y teleósteos. Atlantoraja cyclophora presenta hábitos alimentarios demersal-bentónicos, cambia su dieta con el incremento del tamaño corporal y en respuesta a cambios estacionales y regionales en la disponibilidad y distribución de las presas.(AU)

Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.(AU)

La raya de círculos, Atlantoraja cyclophora , es una especie endémica del Atlántico Sudoccidental, que se distribuye desde Río de Janeiro, Brasil, hasta el norte de la Patagonia, Argentina. Los hábitos alimentarios de esta especie fueron evaluados frente a la costa de Uruguay y norte de Argentina, utilizando un enfoque de modelado de múltiples hipótesis. En general, la dieta estuvo compuesta principalmente por crustáceos decápodos (71,37 %IRI), seguido de peces teleósteos (28,54 %IRI). En menor proporción fueron consumidos moluscos, misidáceos, anfípodos, isópodos, anfioxos y elasmobranquios. El consumo de decápodos Natantia disminuyó con el incremento del tamaño del cuerpo de A. cyclophora . Por otro lado, el consumo de teleósteos se incrementó con el incremento del tamaño del cuerpo. Individuos maduros consumieron cangrejos en mayor proporción que individuos inmaduros. Los teleósteos fueron consumidos mayormente en la región sur (34º - 38ºS) y los cangrejos en la región norte (38º - 41ºS). Los decápodos Natantia fueron más consumidos en la estación cálida que en la estación fría. El tamaño de las presas consumidas se incrementó con el aumento del tamaño corporal de A. cyclophora , pero individuos de mayor tamaño no abandonadon el consumo de pequeños cangrejos y teleósteos. Atlantoraja cyclophora presenta hábitos alimentarios demersal-bentónicos, cambia su dieta con el incremento del tamaño corporal y en respuesta a cambios estacionales y regionales en la disponibilidad y distribución de las presas.(AU)

Description of the first species of Metharpinia (Crustacea: Amphipoda: Phoxocephalidae) from Brazil

A new amphipod species of Metharpinia Schellenberg, 1931 is described from Campos Basin, southeastern Brazilian coast. The material was collected with van Veen grab from unconsolidated substratum, off the mouth of the Paraíba do Sul River. The new species can be distinguished from its congeners by presenting a strongly constricted rostrum and a slender palp of maxilla 1. There are four species in Metharpinia from the South Atlantic: M. dentiurosoma Alonso de Pina, 2003, M. grandirama Alonso de Pina, 2003 and M. iado Alonso de Pina, 2003, and Metharpinia taylorae sp. nov. This is the first record of a species of the genus from Brazilian waters.

Description of the first species of Metharpinia (Crustacea: Amphipoda: Phoxocephalidae) from Brazil

A new amphipod species of Metharpinia Schellenberg, 1931 is described from Campos Basin, southeastern Brazilian coast. The material was collected with van Veen grab from unconsolidated substratum, off the mouth of the Paraíba do Sul River. The new species can be distinguished from its congeners by presenting a strongly constricted rostrum and a slender palp of maxilla 1. There are four species in Metharpinia from the South Atlantic: M. dentiurosoma Alonso de Pina, 2003, M. grandirama Alonso de Pina, 2003 and M. iado Alonso de Pina, 2003, and Metharpinia taylorae sp. nov. This is the first record of a species of the genus from Brazilian waters.(AU)

Inland water microcrustacean assemblages in an altitudinal gradient in Aysen region (46° S, Patagonia Chile) / Crustáceos zooplâncton de águas continentais litorales na gradiente de altitude na região de Aysén (46 ° S, Patagônia Chile)

The Chilean Patagonia has numerous kinds of inland water ecosystems such as lakes, ponds, wetlands and rivers that have been poorly studied due to access difficulties. This study was carried out in Aysen region, in southern Chile, and it included different kinds of water bodies such as rivers, streams, ponds, lagoons and lakes distributed along an altitudinal gradient at 46° S. It was found a low species number, essentially cladocerans, copepods and amphipods. A null model was applied in order to determine the existence of regulator factors of species associations, and the results revealed that they are not random. The patterns would be influenced by geographical and limnological characteristics of the studied sites. Our results would agree with regional studies on habitat heterogeneity such as in Torres del Paine National Park and other zones in Tierra del Fuego island.(AU)

A Patagônia chilena apresenta numerosos tipos de ecossistemas aquáticos, como lagos, lagoas, pântanos e rios, os quais tem sido pouco estudados devido a dificuldades de acesso. Este estudo foi feito na região de Aysén, no sul do Chile, e inclui diferentes tipos de corpos d'água, tais como rios, córregos, lagos, lagoas e lagos distribuídos ao longo de um gradiente de altitude a 46° S. Constatou-se baixo número de espécies que inclui, essencialmente, cladóceros, copépodos e anfípodos. Um modelo nulo foi aplicado para determinar a existência de fatores reguladores das associações de espécies os resultados indicam que estes não são aleatórios. Os padrões poderiam ser influenciados pelas características geográficas e limnológicas do locais estudados. Os resultados expostos concordariam com estudos regionais sobre com habitats heterogeneidade como Torres del Paine Parque Nacional e outras zonas na ilha de Tierra del Fuego.(AU)

First record of Amphipoda Talitroides topitotum (Burt, 1934) (Gammaridea, Talitridae) in the State of Espírito Santo, Brazil / Primeiro registro do Amphipoda Talitroides topitotum (Burt, 1934) (Gammaridea, Talitridae) no Estado do Espírito Santo, Brasil

Talitroides topitotum (Amphipoda) was introduced in Brazil by silviculture activities. Currently the species is distributed in the states of Paraná, Rio de Janeiro and São Paulo. This paper describes the species occurrence in the state of Espírito Santo. The objective of this study was to determine the interference of the edge effect on community structure of macroinvertebrates associated with leaf litter, where a T. topitotum female specimen was observed in coffee cultivations in March 2008.(AU)

Talitroides topitotum (Amphipoda) foi introduzido no Brasil pelas atividades de silvicultura. Atualmente a espécie está distribuída nos Estados do Paraná, Rio de Janeiro e São Paulo. Este trabalho descreve a ocorrência desta espécie no Estado do Espírito Santo. O objetivo deste estudo foi determinar a interferência do efeito de borda na estruturada comunidade de macroinvertebrados associados ao folhiço, onde um espécime fêmea de T. topitotum foi observado em cultivo de café em março de 2008.(AU)

Fish diet composition in permanent and semi-permanent pools in tropical wetlands of the Yucatan Peninsula

We compared fish diet composition between permanent (P) and semi-permanent (SP) pools in Petenes Biosphere Reserve (PBR), Campeche. A total of 445 gut contents were examined to determine stomach relative fullness (RF), fish diet as index of niche breadth (INB) and diet overlap. In SP pools, species showed a RF of 1.66 (57.20 % empty stomachs) whereas in P pools, the RF was 2.91 (31.16%). We classified fish diet into six trophic groups: detritivorous, herbivorous-detritivorous, insectivorous, piscivorous, omnivorous and malacophagous. Species in P pools were found to be specialist. Conversely, species present in both habitats shifted to generalist patterns. There was a 54.0% dissimilarity in fish diet composition between pools. From all items identified, detritus (21.33% of the total dissimilarity), aquatic and terrestrial invertebrates (12.31%), fish remains (10.29%), plant remains (7.37%), and crustaceans (2.74%) distinguished diets between pools. Significant diet overlaps (>0.6) and low INB values (<0.3) were observed in P pools, whereas in SP pools, intermediate-low diet overlaps (<0.4) and higher INB values (>0.5) were observed. In SP pools seasonality had a strong effect on fish diet, increasing the frequency of food items such as terrestrial insects, amphipods and arachnids, during the rainy season while P pools showed lower variation. Thus, fish trophic habits appear to be regulated by pools hydrology.(AU)

Se analizaron y compararon los contenidos estomacales de la ictiofauna en cuerpos de agua permanentes (P) y semi-permanente (SP) de la reserva de la Biosfera Los Petenes, Campeche. Se analizaron un total de 445 estómagos en los cuales se determino la diversidad de dieta (como Índice de amplitud de nicho = INB), plenitud relativa de estómagos (PRE) y traslape de dietas. En las pozas SP 57.20 % de los estómagos se encontraron vacíos y los estómagos con alimento presentaron un PRE de 1.66. En las pozas P solo el 31.16 % de los estómagos se encontraron vacíos y un PRE de 2.91. Los peces se clasificaron en seis grupos tróficos: detritívoros, herbívoros-detritívoros, insectívoros, piscívoros, omnívoros y malacófagos. Los individuos en la pozas P tendieron a presentar dietas especializadas mientras que en las pozas SP patrones generalistas. Se observo una disimilitud de dietas entre pozas del 54.0 % asociada a los items: detritus (21.33%), invertebrados acuáticos y terrestres (12.31%), fragmentos de peces (10.29%), fragmentos de vegetación (7.37%) y crustáceos (2.74%). Los mayores traslapes de dietas (> 0.6) y menores INB (< 0.3) se observaron en especies presentes en las pozas P mientras que en las pozas SP se observaron valores de traslape intermedios-bajos (<0.4) e INB mayores (> 0.5) en especies que utilizaron mayores fuentes de alimento. En las pozas SP la estacionalidad tuvo una marcada influencia en la proporción de los ítems: insectos acuáticos, anfípodos y arácnidos, los cuales presentaron mayores frecuencias, sobre todo en la época de lluvias, mientras que las pozas P no presentaron cambios significativos. Los resultados sugieren que los peces en pozas de la RBP modifican su dieta en función de la hidrología de los cuerpos de agua, con un patrón trófico particular a escala regional comparado con otros cuerpos de agua estacionales en Centro y América del Sur.(AU)

Variações ontogênicas e sazonais na dieta de Etropus crossotusJordan e Gilbert, 1882 ( Paralichthydae ) na baía de Ubatuba-Enseada,Estado de Santa Catarina, Brasil / Ontogenetic and seasons changes in the diet of Etropus crossotus Jordan and Gilbert, 1882 ( Paralichthydae ) at Ubatuba-Enseada Bay, Santa Catarina State, Brazil

Foram investigadas as variações ontogênicas e sazonais na dieta de Etropuscrossotus coletados na baía de Ubatuba-Enseada, Estado de Santa Catarina, Brasil. Redes dearrasto com porta foram utilizadas para as coletas mensais, e 60 exemplares foram coletadosentre outubro de 2003 e setembro de 2004. Maior similaridade entre os Índices deImportância Alimentar foi observada entre a primavera e o outono. Crustáceos decápodesrepresentaram 50% dos itens alimentares durante a primavera e outono, e crustáceosanfípodes foram os itens mais representativos no inverno. Maior similaridade entre os IAifoi observada entre as classes 1, 2 e 4, pela alta representatividade de Decapoda, e entre asclasses 5, 6 e 7, em função da representatividade de Decapoda e Amphipoda. Os resultadosobtidos foram similares a outros estudos realizados na região costeira Sul do Brasil.(AU)

Ontogenetic and seasonal changes in the diet of Etropus crossotussampled at Ubatuba-Enseada Bay in Santa Catarina State, Brazil were investigated. A trawlnet was used for the surveys, and 60 fish were collected monthly during October (2003) andSeptember (2004). The highest similarity of the Alimentary Importance Index (AII) wasobserved between spring and autumn. Crustacea Decapoda represented 50% of the feedingitems during spring and fall, and Crustacea Amphipoda were the most representative itemin winter. The highest AII similarity was observed among length classes 1, 2 and 4, whichwas related to Decapoda representation, and among length classes 5, 6 and 7, because ofDecapoda and Amphipoda importance. Results were similar to other studies in the southerncoast of Brazil.(AU)

Diel density variation of amphipods associated with Sargassum beds from two shores of Ubatuba, Southeastern, Brazil

Densities of mobile epifaunal assemblages associated with macrophytes are very variable during the day and the activity of visually-oriented predators is thought to have an important influence on this pattern. Here we compared densities of amphipods associated with a common brown alga, Sargassum stenophyllum (Phaeophyceae), at sites contrasting in water turbidity. We expected that diel variation of amphipods would occur in a shore with clear waters (Perequê), whereas no variation was expected in a shore with turbid waters (Lamberto). Amphipod density varied during the day at both shores, with no indication of a larger variation at Perequê. Most species showed two density peaks, one at night and the other in the afternoon. These peaks occurred close the times of high tide, suggesting that tidal rhythms could influence more amphipod densities than the activity of predators. Thus, more studies are necessary to understand factors that influence short-term variation of epifaunal assemblages.

As densidades da epifauna móvel associada a macrófitas variam muito ao longo do dia, sendo a atividade de predadores visualmente orientados um dos principais fatores apontados para explicar este padrão. Neste estudo, comparamos as densidades de anfípodos associados a uma alga parda comum, Sargassum stenophyllum (Phaeophyceae), em praias contrastando em turbidez da água. Era esperada a ocorrência de variação ao longo do dia numa praia com águas claras (Perequê) e nenhuma variação na praia com águas turvas (Lamberto). A densidade de anfípodos variou ao longo do dia em ambas as praias, sem indicação de maior variação em Perequê. A maioria das espécies apresentou dois picos de densidade: um à noite e outro à tarde. Estes ocorreram próximos aos períodos de maré alta, sugerindo que o ritmo de maré poderia influenciar mais as densidades de anfípodos que a atividade de predadores. Assim, mais estudos são necessários para se compreender os fatores que influenciam a variação de curto prazo das comunidades epifaunais.

Diel density variation of amphipods associated with Sargassum beds from two shores of Ubatuba, Southeastern, Brazil

Densities of mobile epifaunal assemblages associated with macrophytes are very variable during the day and the activity of visually-oriented predators is thought to have an important influence on this pattern. Here we compared densities of amphipods associated with a common brown alga, Sargassum stenophyllum (Phaeophyceae), at sites contrasting in water turbidity. We expected that diel variation of amphipods would occur in a shore with clear waters (Perequê), whereas no variation was expected in a shore with turbid waters (Lamberto). Amphipod density varied during the day at both shores, with no indication of a larger variation at Perequê. Most species showed two density peaks, one at night and the other in the afternoon. These peaks occurred close the times of high tide, suggesting that tidal rhythms could influence more amphipod densities than the activity of predators. Thus, more studies are necessary to understand factors that influence short-term variation of epifaunal assemblages.

As densidades da epifauna móvel associada a macrófitas variam muito ao longo do dia, sendo a atividade de predadores visualmente orientados um dos principais fatores apontados para explicar este padrão. Neste estudo, comparamos as densidades de anfípodos associados a uma alga parda comum, Sargassum stenophyllum (Phaeophyceae), em praias contrastando em turbidez da água. Era esperada a ocorrência de variação ao longo do dia numa praia com águas claras (Perequê) e nenhuma variação na praia com águas turvas (Lamberto). A densidade de anfípodos variou ao longo do dia em ambas as praias, sem indicação de maior variação em Perequê. A maioria das espécies apresentou dois picos de densidade: um à noite e outro à tarde. Estes ocorreram próximos aos períodos de maré alta, sugerindo que o ritmo de maré poderia influenciar mais as densidades de anfípodos que a atividade de predadores. Assim, mais estudos são necessários para se compreender os fatores que influenciam a variação de curto prazo das comunidades epifaunais.

Alimentación del barbo Genidens genidens Valenciennes, 1839 en un banco de arena de arena y lodo en Ilha do Mel, Paraná, Brasil / The feeding of the catfish Genidens genidens Valenciennes, 1839 in a muddy sandbank, Ilha do Mel, Paraná, Brazil / A alimentação do bagre Genidens genidens Valenciennes, 1839 em um banco areno-lodoso da Ilha do Mel, Paraná, Brasil

Se estudió la alimentación del barbo Genidens genidens y se determinó la composición y la variación estacional de su alimento. Los contenidos del estómago de 48 barbos capturados con una red de arrastrar con puertas de 20 x 35 metros y trama de 1 cm, siempre en los períodos máximos de pleamar, entre julio de 1991 y junio de 1992. Emplearanse los métodos de frecuencia de ocurrencia, volumétrico y índice de importancia del alimento. El barbo no mostró variaciones significantes en tamaño medio (27,83 ± 2,91 cm) y peso (196,82 ± 80,12 g). La existencia del barbo durante todas las estaciones del año y en toda la bahía de Paranaguá permisos la conclusión que la especie vive en este estuario. Los artículos alimentarios más frecuentemente encontrados en el estómago de los barbos eras sedimentos, crustáceos decapodos, crustáceos anfipodos y polychaetas. Entre los decapodos la presencia de piernas y fragmentos de las garras se observó notablemente, representando Alpheus heterochaelis, Penaeus schmitti y Xanthidae. Los artículos alimentarios más importantes encontrados en invierno fueran crustáceos decapodos, sedimentos, anfipodos y tubos de Corophidae. En la primavera fueran encontrados sedimentos y crustáceos decapodos, principalmente Alpheus heterochaelis y Hexapanopeus schmitti. Los artículos alimentarios encontrados en el verano y otoño fueran sedimentos y fragmentos de crustáceos de

It was studied the feeding of the catfish Genidens genidens, determining the composition and seasonal variation of its feed. The stomach contents of 48 catfishes captured with a trawl net with doors 20 x 35 meters, 1 cm mesh, between July, 1991 and June, 1992 were analysed through the methods of frequency of occurrence, volumetric and alimentary index. The catfish didnt show significant variations in average lengh (27.83 ± 2.91 cm) and weight (196.82 ± 80.12 g). The existence of the catfish during all seasons of the year and all over the Paranaguá bay permits the conclusion that the species lives in this estuary. The alimentary items found more frequently in the stomachs were sediment, decapod crustaceans, anphipod crustaceans and polychaetas. Among the decapods the presence of walking legs and claws fragments was remarkably observed, representatives of Alpheus heterochaelis, Penaeus schimitti and Xanthidae. The most important items found in winter were decapod crustaceans, sediments, anphipods and tubes of Corophidae. The items found in spring were sediments and decapod crustaceans, mainly the A. heterochaelis and Hexapanopeus schmitti. The items found in summer and autumn were sediments and fragments of decapods crustaceans. The feeding of the G. genidens in the muddy sandbank studied was influenced by the environmental status of each season of the year due to the alternatio

Foi avaliada a variação sazonal da alimentação do bagre Genidens genidens em um banco areno-lodoso na Ilha do Mel, bem como observada as variações por classes de comprimento, peso, estádio de maturação gonadal e número de anéis de crescimento. As coletas foram realizadas entre os meses de julho de 1991 e junho de 1992 através de uma rede de arrasto com portas com 20 m de boca e 35 m de comprimento, com malha de 1 cm, sempre nos períodos de amplitude máxima de marés de sizígia (lua cheia). Foram analisados 48 estômagos através dos métodos de freqüência de ocorrência, volumétrico e índice alimentar. Os itens de maior importância foram crustáceos (decápodos - 41,72% - Alpheus heterochaelis, Xanthidae, Eurytium limosum, Hexapanopeus schmitti, Portunidae, Paguridae e Brachyura; anfípodos - 4,69% - Corophidae e Caprellidae), material não identificado (42,32%) e poliquetas (1,15% - Armandia e Glycinde multidens). Constatou-se que G. genidens apresenta a dieta influenciada pelas variações sazonais, e que está usando o banco areno-lodoso como local de alimentação. Variações significativas de comprimento (27,83 ± 2,91cm) e peso (196,82 ± 80,12g) não foram observadas, e a maioria dos indivíduos apresentou as gônadas nos estádios imaturo e em maturação com 5,4 ± 0,46 anéis de crescimento. Para a região estudada existe uma forte predominância de crustáceos decápodos na alimentação deste

Alimentación del barbo Genidens genidens Valenciennes, 1839 en un banco de arena de arena y lodo en Ilha do Mel, Paraná, Brasil / The feeding of the catfish Genidens genidens Valenciennes, 1839 in a muddy sandbank, Ilha do Mel, Paraná, Brazil / A alimentação do bagre Genidens genidens Valenciennes, 1839 em um banco areno-lodoso da Ilha do Mel, Paraná, Brasil

Se estudió la alimentación del barbo Genidens genidens y se determinó la composición y la variación estacional de su alimento. Los contenidos del estómago de 48 barbos capturados con una red de arrastrar con puertas de 20 x 35 metros y trama de 1 cm, siempre en los períodos máximos de pleamar, entre julio de 1991 y junio de 1992. Emplearanse los métodos de frecuencia de ocurrencia, volumétrico y índice de importancia del alimento. El barbo no mostró variaciones significantes en tamaño medio (27,83 ± 2,91 cm) y peso (196,82 ± 80,12 g). La existencia del barbo durante todas las estaciones del año y en toda la bahía de Paranaguá permisos la conclusión que la especie vive en este estuario. Los artículos alimentarios más frecuentemente encontrados en el estómago de los barbos eras sedimentos, crustáceos decapodos, crustáceos anfipodos y polychaetas. Entre los decapodos la presencia de piernas y fragmentos de las garras se observó notablemente, representando Alpheus heterochaelis, Penaeus schmitti y Xanthidae. Los artículos alimentarios más importantes encontrados en invierno fueran crustáceos decapodos, sedimentos, anfipodos y tubos de Corophidae. En la primavera fueran encontrados sedimentos y crustáceos decapodos, principalmente Alpheus heterochaelis y Hexapanopeus schmitti. Los artículos alimentarios encontrados en el verano y otoño fueran sedimentos y fragmentos de crustáceos de

It was studied the feeding of the catfish Genidens genidens, determining the composition and seasonal variation of its feed. The stomach contents of 48 catfishes captured with a trawl net with doors 20 x 35 meters, 1 cm mesh, between July, 1991 and June, 1992 were analysed through the methods of frequency of occurrence, volumetric and alimentary index. The catfish didnt show significant variations in average lengh (27.83 ± 2.91 cm) and weight (196.82 ± 80.12 g). The existence of the catfish during all seasons of the year and all over the Paranaguá bay permits the conclusion that the species lives in this estuary. The alimentary items found more frequently in the stomachs were sediment, decapod crustaceans, anphipod crustaceans and polychaetas. Among the decapods the presence of walking legs and claws fragments was remarkably observed, representatives of Alpheus heterochaelis, Penaeus schimitti and Xanthidae. The most important items found in winter were decapod crustaceans, sediments, anphipods and tubes of Corophidae. The items found in spring were sediments and decapod crustaceans, mainly the A. heterochaelis and Hexapanopeus schmitti. The items found in summer and autumn were sediments and fragments of decapods crustaceans. The feeding of the G. genidens in the muddy sandbank studied was influenced by the environmental status of each season of the year due to the alternatio

Foi avaliada a variação sazonal da alimentação do bagre Genidens genidens em um banco areno-lodoso na Ilha do Mel, bem como observada as variações por classes de comprimento, peso, estádio de maturação gonadal e número de anéis de crescimento. As coletas foram realizadas entre os meses de julho de 1991 e junho de 1992 através de uma rede de arrasto com portas com 20 m de boca e 35 m de comprimento, com malha de 1 cm, sempre nos períodos de amplitude máxima de marés de sizígia (lua cheia). Foram analisados 48 estômagos através dos métodos de freqüência de ocorrência, volumétrico e índice alimentar. Os itens de maior importância foram crustáceos (decápodos - 41,72% - Alpheus heterochaelis, Xanthidae, Eurytium limosum, Hexapanopeus schmitti, Portunidae, Paguridae e Brachyura; anfípodos - 4,69% - Corophidae e Caprellidae), material não identificado (42,32%) e poliquetas (1,15% - Armandia e Glycinde multidens). Constatou-se que G. genidens apresenta a dieta influenciada pelas variações sazonais, e que está usando o banco areno-lodoso como local de alimentação. Variações significativas de comprimento (27,83 ± 2,91cm) e peso (196,82 ± 80,12g) não foram observadas, e a maioria dos indivíduos apresentou as gônadas nos estádios imaturo e em maturação com 5,4 ± 0,46 anéis de crescimento. Para a região estudada existe uma forte predominância de crustáceos decápodos na alimentação deste