Parasites of the Shiny Cowbird, Molothrus bonariensis, and the Austral Blackbird, Curaeus curaeus, (Passeriformes: Icteridae) in Chile / Parasitas do chupim Molothrus bonariensis e do pássaro-preto-austral Curaeus curaeus (Passeriformes: Icteridae) no Chile

Comparative studies of parasites in sympatric bird species have been generally scarce. Parasitic infection/transmission can be spread in a number of ways that suggests possible direct and indirect, horizontal transmission between avian hosts. In order to determine whether two sympatric icterids from Central and Southern Chile share their parasite fauna (ecto- and endoparasites), we examined parasites of 27 Shiny Cowbirds, Molothrus bonariensis, and 28 Austral Blackbirds, Curaeus curaeus, including individuals captured in the wild and carcasses. We found that Shiny Cowbirds were infected with the chewing lice Brueelia bonariensis, Philopterus sp. 1, the feather mites Amerodectes molothrus, Proctophyllodes spp. (species 1 and 2), and the helminths Mediorhynchus papillosus, Plagiorhynchus sp., Dispharynx nasuta and Tetrameres paucispina, while Austral Blackbirds had the chewing lice Myrsidea sp., Philopterus sp. 2, the feather mites Proctophyllodes sp. 3, Amerodectes sp., and three helminths: Anonchotaenia sp., Capillaria sp. and M. papillosus. The flea Dasypsyllus (Neornipsyllus) cteniopus was found only on the Austral Blackbird. The only parasite species shared by both icterids was the acanthocephalan M. papillosus, possibly due to their feeding on the same intermediate insect hosts. With the exception of B. bonariensis and Philopterus sp. 1 found on the Shiny Cowbird, all species reported in this study represent new parasite-host associations and new records of parasite diversity in Chile.(AU)

Estudos comparativos de parasitas em espécies de aves simpátricas são escassos. A infecção/transmissão de parasitas pode acontecer de diversas maneiras, incluindo possível transmissão direta, indireta ou horizontal entre as aves hospedeiras. Com o objetivo de determinar se dois icterídeos simpátricos do centro e sul do Chile compartilham a sua fauna parasitária (ecto- e endoparasitas), foram examinados os parasitas de 27 chupins Molothrus bonariensis e 28 pássaros-pretos-austral Curaeus curaeus, incluindo indivíduos capturados com rede de neblina e em carcaças. Nos chupins analisados, foram encontrados os piolhos de penas Brueelia bonariensis, Philopterus sp. 1, os ácaros Amerodectes molothrus, Proctophyllodes spp. (espécie 1 e 2), e os helmintos Mediorhynchus papillosus, Plagiorhynchus sp., Dispharynx nasuta e Tetrameres paucispina. Em contraste, os pássaros-pretos-austral estavam infectados com os piolhos Myrsidea sp., Philopterus sp. 2, os ácaros Proctophyllodes sp. 3, Amerodectes sp., e os helmintos Anonchotaenia sp., Capillaria sp. e M. papillosus. Adicionalmente, um espécime de pássaro-preto-austral estava parasitado pela pulga Dasypsyllus (Neornipsyllus) cteniopus. A única espécie de parasita que foi encontrada nas duas espécies de aves foi o acantocéfalo M. papillosus, possivelmente devido ao fato de que ambas as aves se alimentam dos insetos que são os hospedeiros intermediários deste parasita. Exceto os registros de B. bonariensis e Philopterus sp. 1 encontrados no chupim, todas as espécies reportadas neste estudo correspondem à novas associações de parasita/hospedeiro e novos registros para a diversidade parasitológica do Chile.(AU)

Re-examining the hypothesis of allopatric distribution of Myoprocta acouchy and M pratti (Mammalia Dasyproctidae) in south america

Currently, two allopatric species of acouchies, genus Myoprocta (Rodentia: Dasyproctidae) are recognized. Nevertheless, there is morphological variability in the regions where the species are distributed that suggests either sympatry of two (or more) distinct species or else breakdowns in the characters that have been used to diagnose the species. We reviewed specimens of Myoprocta from Colombia and found that both reddish and greenish forms are sympatric in the Amazon basin of the country, including areas adjoining Ecuador and Peru. These records apparently refute the hypothesis of allopatry for these species in South America. However, the results of a principal components analysis showed little or no morphological separation between these two forms. In addition, a review of skulls throughout the geographic range of M. pratti shows high morphological variation. Although sympatry of reddish and greenish acouchies has been suggested for the Amazon region of Ecuador, our review found no evidence of this. In view of our findings, further revisionary work is needed to clarify the status of these forms.

Re-examining the hypothesis of allopatric distribution of Myoprocta acouchy and M pratti (Mammalia Dasyproctidae) in south america

Currently, two allopatric species of acouchies, genus Myoprocta (Rodentia: Dasyproctidae) are recognized. Nevertheless, there is morphological variability in the regions where the species are distributed that suggests either sympatry of two (or more) distinct species or else breakdowns in the characters that have been used to diagnose the species. We reviewed specimens of Myoprocta from Colombia and found that both reddish and greenish forms are sympatric in the Amazon basin of the country, including areas adjoining Ecuador and Peru. These records apparently refute the hypothesis of allopatry for these species in South America. However, the results of a principal components analysis showed little or no morphological separation between these two forms. In addition, a review of skulls throughout the geographic range of M. pratti shows high morphological variation. Although sympatry of reddish and greenish acouchies has been suggested for the Amazon region of Ecuador, our review found no evidence of this. In view of our findings, further revisionary work is needed to clarify the status of these forms.(AU)

Food niche overlap between two sympatric leaf-litter frog species from Central Amazonia

We studied the feeding habits and similarities in the diet of two sympatric and syntopic Amazonian frog species, Anomaloglossus stepheni (Aromobatidae) and Leptodactylus andreae (Leptodactylidae) in a forested area in Central Amazonia. The breadth of the trophic niche of these species was 5.89 and 3.75, respectively, and approximately 85% of their diets were similar. Ants were main food item in the diets of both frog species. The coexistence between these frog species may be facilitated by the significant differences in the size of their mouths. This difference allows them to consume preys items of different sizes.

Food niche overlap between two sympatric leaf-litter frog species from Central Amazonia

We studied the feeding habits and similarities in the diet of two sympatric and syntopic Amazonian frog species, Anomaloglossus stepheni (Aromobatidae) and Leptodactylus andreae (Leptodactylidae) in a forested area in Central Amazonia. The breadth of the trophic niche of these species was 5.89 and 3.75, respectively, and approximately 85% of their diets were similar. Ants were main food item in the diets of both frog species. The coexistence between these frog species may be facilitated by the significant differences in the size of their mouths. This difference allows them to consume preys items of different sizes.

Food niche overlap between two sympatric leaf-litter frog species from Central Amazonia

We studied the feeding habits and similarities in the diet of two sympatric and syntopic Amazonian frog species, Anomaloglossus stepheni (Aromobatidae) and Leptodactylus andreae (Leptodactylidae) in a forested area in Central Amazonia. The breadth of the trophic niche of these species was 5.89 and 3.75, respectively, and approximately 85% of their diets were similar. Ants were main food item in the diets of both frog species. The coexistence between these frog species may be facilitated by the significant differences in the size of their mouths. This difference allows them to consume preys items of different sizes.

Pleistocene karyotypic divergence in Hoplias malabaricus (Bloch, 1794) (Teleostei: Erythrinidae) populations in southeastern Brazil

The lacustrine system of the middle rio Doce basin is considered a paradigm of Pleistocene geomorphology. In these lakes, two Hoplias malabaricus karyomorphs (2n = 42A and 2n = 42B) live in sintopy in Carioca Lake. Cytogenetic analyses were performed on 65 specimens from 8 lakes (including Carioca Lake) to determine the distribution and relative frequency of these karyomorphs and the degree of cytogenetic divergence caused putatively by recent geographic isolation. All fish were 2n = 42B karyomorphs, except for 1 specimen from the Marola Lake, which was 2n = 42A. Among-population variation was especially high for C-banding patterns. Other characters such as X chromosome size and CMA3/DAPI also varied among populations. Our results suggested that the karyotype of H. malabaricus is able to respond rapidly to geographic isolation, and revealed that heterochromatic variation may represent the lowest hierarchical level of chromosomal evolution.(AU)

O sistema lacustre da bacia do médio rio Doce é considerado um paradigma da geomorfologia do Pleistoceno. Nestes lagos, dois cariomorfos de Hoplias malabaricus (2n = 42A e 2n = 42B) vivem em sintopia na lagoa Carioca. Análises citogenéticas foram realizadas em 65 amostras de 8 lagos (incluindo lagoa Carioca) para determinar a distribuição e frequência relativa destes cariomorfos e o grau de divergência citogenética aparentemente causada pelo isolamento geográfico recente. Todos os peixes apresentaram o cariomorfo 2n = 42B, com exceção de 1 espécime da lagoa Marola, que foi 2n = 42A. Entre as populações, a variação foi especialmente elevada nos padrões de bandamento C. Outros caracteres como o tamanho do cromossomo X e os padrões de CMA3/DAPI também variaram entre as populações. Nossos resultados sugerem que o genoma de H. malabaricus é capaz de responder rapidamente ao isolamento geográfico, revelando que a variação de heterocromatina pode representar o nível hierárquico mais baixo de evolução cromossômica.(AU)

Comparative dietary analysis of Eurycheilichthys pantherinus and Pareiorhaphis hystrix: two Loricariidae species (Ostariophysi, Siluriformes) from Campos Sulinos biome, southern Brazil

This work was carried out in Marco river, São José dos Ausentes municipality, state of Rio Grande do Sul, southern Brazil. This region is located within the Campos Sulinos biome, an area of great biological importance due to its high diversity and endemism of fish. The feeding habits and food overlap between Eurycheilichthys pantherinus (Reis & Schaefer, 1992) (n=108) and Pareiorhaphis hystrix Pereira & Reis, 2002 (n=60) are described. Monthly samples were obtained between September 2000 and July 2001 with dipnets using the kick sampling technique. Stomach contents were analyzed based on frequency of occurrence, volumetric frequency and index of alimentary importance. The level of dietary specialization and food overlap were determined by the Levins measure and the Morisita index, respectively. Eurycheilichthys pantherinus fed mainly on immature aquatic insects, such as Dipterans and Ephemeropterans, and was classified as insectivore. Pareiorhaphis hystrix fed mainly on detritus associated with small amounts of aquatic insects, and was classified as detritivore. Species are clearly segregated by the use of food resources in Marco River. Their diets did not overlap and the differences observed in their feeding habits probably contribute for their coexistence.

Este estudo foi realizado no rio do Marco, município de São José dos Ausentes, estado do Rio Grande do Sul, sul do Brasil. Esta região está inserida no bioma Campos Sulinos, considerada uma área de grande importância biológica devido à grande diversidade e endemismo de peixes. Este trabalho tem como objetivos descrever os hábitos alimentares e verificar a presença de sobreposição alimentar na dieta de duas espécies simpátricas de Loricariidae do rio do Marco: Eurycheilichthys pantherinus (Reis & Schaefer, 1992) (n=108) e Pareiorhaphis hystrix Pereira & Reis, 2002 (n=60). Os espécimes foram coletados mensalmente, entre setembro de 2000 e julho de 2001 com redes do tipo puçá utilizando a técnica de kick sampling. Os conteúdos estomacais foram analisados através dos métodos de frequência de ocorrência, frequência volumétrica e índice de importância alimentar. O grau de especialização alimentar e a sobreposição nas dietas foram calculadas através da medida de Levins e do índice de Morisita, respectivamente. Eurycheilichthys pantherinus alimentou-se preferencialmente de formas imaturas de insetos aquáticos, tais como Diptera e Ephemeroptera, apresentando o hábito alimentar insetívoro. Pareiorhaphis hystrix alimentou-se de detrito associado a pequenas quantidades de insetos aquáticos, apresentando o hábito alimentar detritívoro. As espécies estão claramente segregadas quanto ao uso dos recursos alimentares no rio do Marco e possivelmente as diferenças nos hábitos alimentares contribuem para sua coexistência.

Comparative dietary analysis of Eurycheilichthys pantherinus and Pareiorhaphis hystrix: two Loricariidae species (Ostariophysi, Siluriformes) from Campos Sulinos biome, southern Brazil

This work was carried out in Marco river, São José dos Ausentes municipality, state of Rio Grande do Sul, southern Brazil. This region is located within the Campos Sulinos biome, an area of great biological importance due to its high diversity and endemism of fish. The feeding habits and food overlap between Eurycheilichthys pantherinus (Reis & Schaefer, 1992) (n=108) and Pareiorhaphis hystrix Pereira & Reis, 2002 (n=60) are described. Monthly samples were obtained between September 2000 and July 2001 with dipnets using the kick sampling technique. Stomach contents were analyzed based on frequency of occurrence, volumetric frequency and index of alimentary importance. The level of dietary specialization and food overlap were determined by the Levins measure and the Morisita index, respectively. Eurycheilichthys pantherinus fed mainly on immature aquatic insects, such as Dipterans and Ephemeropterans, and was classified as insectivore. Pareiorhaphis hystrix fed mainly on detritus associated with small amounts of aquatic insects, and was classified as detritivore. Species are clearly segregated by the use of food resources in Marco River. Their diets did not overlap and the differences observed in their feeding habits probably contribute for their coexistence.

Este estudo foi realizado no rio do Marco, município de São José dos Ausentes, estado do Rio Grande do Sul, sul do Brasil. Esta região está inserida no bioma Campos Sulinos, considerada uma área de grande importância biológica devido à grande diversidade e endemismo de peixes. Este trabalho tem como objetivos descrever os hábitos alimentares e verificar a presença de sobreposição alimentar na dieta de duas espécies simpátricas de Loricariidae do rio do Marco: Eurycheilichthys pantherinus (Reis & Schaefer, 1992) (n=108) e Pareiorhaphis hystrix Pereira & Reis, 2002 (n=60). Os espécimes foram coletados mensalmente, entre setembro de 2000 e julho de 2001 com redes do tipo puçá utilizando a técnica de kick sampling. Os conteúdos estomacais foram analisados através dos métodos de frequência de ocorrência, frequência volumétrica e índice de importância alimentar. O grau de especialização alimentar e a sobreposição nas dietas foram calculadas através da medida de Levins e do índice de Morisita, respectivamente. Eurycheilichthys pantherinus alimentou-se preferencialmente de formas imaturas de insetos aquáticos, tais como Diptera e Ephemeroptera, apresentando o hábito alimentar insetívoro. Pareiorhaphis hystrix alimentou-se de detrito associado a pequenas quantidades de insetos aquáticos, apresentando o hábito alimentar detritívoro. As espécies estão claramente segregadas quanto ao uso dos recursos alimentares no rio do Marco e possivelmente as diferenças nos hábitos alimentares contribuem para sua coexistência.

Distribution patterns and trophic characteristics of salmonids and native species inhabiting high altitude rivers of Pampa de Achala region, Argentina

The Pampa de Achala in central Argentina is an area with low fish species richness where salmonids were first introduced at the beginning of the twentieth century. A total of 19 rivers of different order were sampled during the low water period by using portable electrofishing equipment. We covered different identified macrohabitats (pools, riffles, glides and cascades) in reaches of 300-500 m length. The native species Trichomycterus corduvensis and two exotic salmonids such as Salvelinus fontinalis and Oncorhynchus mykiss represented the most common species, showing allopatric and sympatric distribution in some streams. Stomach contents and diet overlapping were also analyzed. Cluster results showed a first main group comprised those streams with high diet similitude between T. corduvensis and O. mykiss whereas a second main group consisted of streams with high diet similitude between O. mykiss and S. fontinalis. Mean niche width was similar among all these species but T. corduvensis showed that widest range whereas S. fontinalis exhibited the narrowest trophic niche. We were able to document a direct predation on T. corduvensis by O. mykiss in two stream although distribution overlapping among native and exotic species were low. In turn diet overlapping among species were negligible. Trophic niche amplitude of S. fontinalis was inversely related to stream order, providing clues that geomorphology and hydrology may exert also influence of trophic characteristics and can be used for predicting the potential for food competition with native species. Analysis by Tokeshi plot revealed that T. corduvensis ranged from specialist to generalist whereas both salmonids showed generalist feeding habits with a heterogeneous and homogeneous diet.(AU)

El área de Pampa de Achala, en el centro de Argentina, posee una baja riqueza específica y donde los salmónidos fueron introducidos al comienzo del siglo XX. Se muestrearon 19 ríos de diferente orden durante el período de aguas bajas utilizando un equipo de pesca eléctrica portátil. Se cubrieron diferentes macrohábitats (pozones, correderas, tablas y cascadas) en tramos de 300 a 500 m de longitud. Las especie nativa Trichomycterus corduvensis y dos salmódios exóticos, Salvelinus fontinalis y Oncorhynchus mykiss, representaron las especies más comunes mostrando distribuiciones alopátricas y simpátricas en algunos de estos ríos. Se analizaron los contenidos estomacales y la superposición de sus dietas. El análisis por agrupamiento puso en evidencia un primer gran grupo compuesto por aquellos ríos con alta similitud de dieta entre T. corduvensis y O. mykiss, ancho medio de nicho fue similar entre estas especies pero T. corduvensis exhibió el rango de mayor amplitud y S. fontinalis que la superposición de distribución entre especies nativas y exóticas fue escasa. Por su parte, la superposición de dietas entre estas especies fue muy baja. La amplitud de nicho trófico de S. fontinalis estuvo inversamente correlacionada con el orden del río, proporcionando indicios que la geomorfología y hidrología podrían influir sobre las características tróficas y podrían ser utilizadas para predecir la competencia potencial con las especies nativas . El análisis mediante gráficos de Tokeshi reveló que T. corduvensis se comportó como especialista a generalista mientras ambos salmónidos mostraron hábitos generalistas con dietas homogéneas y heterogéneas.(AU)

Padrões de distribuição e diversidade genética das espécies Didelphis albiventris, Didelphis marsupialis e Didelphis aurita (Didelphimorphia: Didelphidae) de ocorrência no Nordeste brasileiro

As espécies do gênero Didelphis são conhecidas popularmente no Brasil como mucuras, timbus e sariguês. Seis são endêmicas das Américas: cinco ocorrem na América do Sul e uma na América do Norte (D. virginiana). As espécies desse gênero são classificadas em dois grupos: albiventris (gambás-de-orelhas-brancas) e marsupialis (gambás-deorelhas-pretas), das quais quatro ocorrem no Brasil (D. albiventris, D. imperfecta, D. marsupialis e D. aurita). D. aurita é endêmica da Mata Atlântica, D. albiventris é típica do Cerrado, D. marsupialis e D. imperfecta ocorrem na Amazônia. Devido às semelhanças morfológicas, D. aurita e D. marsupialis são identificadas somente por dados moleculares e morfométricos. Neste estudo, objetivou-se compreender os padrões de distribuição e diversidade genética das espécies D. albiventris, D. marsupialis e D. aurita de ocorrência no Nordeste brasileiro, a fim de se inferir quanto à sua problemática taxonômica e biogeográfica. Para tanto, analisaram-se (n=63) amostras das espécies D. albiventris (n=52), D. marsupialis (n=8) e D. aurita (n=4) provenientes de sete estados da região Nordeste do Brasil: Alagoas, Sergipe, Pernambuco, Paraíba, Ceará, Piauí e Maranhão, compreendendo os biomas: Cerrado, Caatinga e Mata Atlântica. Para obtenção dos dados moleculares, fez-se extração do DNA a partir de tecidos musculares, fígado, pele e cauda e fez-se amplificação e sequenciamento dos genes rRNA 16S, Citocromo b e Citocromo Oxidase I. Para a análise dos dados, utilizaram-se softwares específicos, bem como plataformas bioinformáticas de livre acesso. Os dados gerados a partir dos três marcadores moleculares foram eficientes e revelaram o monofiletismo de D. albiventris para a região Nordeste do Brasil, a identificação de D. marsupialis para o Cerrado maranhense; confirmando, assim, sua expansão para o leste maranhense e uma linhagem distinta de D. aurita para a Mata Atlântica alagoana. O estudo de populações para D. albiventris nos diferentes estados da região Nordeste e diferentes biomas não evidenciaram estruturação populacional indicando ausência de barreiras biológicas na área de distribuição analisada. Este estudo permitiu ainda inferir quanto à simpatria dos grupos de Didelphis para as espécies D. albiventris e D. marsupialis no Cerrado maranhense, registro raro para essas espécies.

The species of the genus Didelphis are known popularly in Brazil as mucuras, timbus and sariguês (opossum or possum in English for all of them). Six are endemic to the Americas: five occur in South America and one in North America (D. virginiana). The species of this genus are classified into two groups: albiventris (opossum-the-earswhite) and marsupialis (opossums-of-ears-black), of which four occur in Brazil (D. albiventris, D. imperfecta, D. marsupialis and D. aurita). D. aurita is endemic to the Atlantic Forest, D. albiventris is typical of the Cerrado, D. marsupialis and D. imperfecta occur in Amazônia. Due to morphological similarities, D. aurita and D. marsupialis are identified only by molecular and morphometric data. In this study, it was aimed to understand the distribution patterns and genetic diversity of the species D. albiventris, D. marsupialis and D. aurita that occur in Brazilian Northeast, in order to infer as to its taxonomic and biogeographic problems. For that, it were analyzed samples (n=63) of the species D. albiventris (n=52), D. marsupialis (n=8) and D. aurita (n=4) from seven states in the Northeast of Brazil: Alagoas, Sergipe, Pernambuco, Paraíba, Ceará, Piauí and Maranhão, comprising the biomes Cerrado, Caatinga and Atlantic Forest. To get the molecular data, it was made DNA extraction from muscle tissue, liver, skin and tail and there was amplification and sequencing of rRNA 16S genes, Cytochrome b and Cytochrome Oxidase I. For the analysis of data, it were used specific software programs as well as bioinformatics platforms of free access. The data generated from the three molecular markers were efficient and showed the monophyly of D. albiventris in the Northeast region of Brazil, the identification of D. marsupialis for the Cerrado of Maranhão; thereby confirming its expansion to the east of Maranhão and distinct lineage of D. aurita for the Atlantic Forest in Alagoas. The populations study for D. albiventris in different states in the Northeast and different biomes did not evidence population structure indicating absence of biological barriers in the area of analyzed distribution. This study also allowed inferring as the sympatry of Didelphis groups for the species D. albiventris and D. marsupialis in the Cerrado of Maranhão, rare record for these species.

On the type material of Scyllarides deceptor Holthuis, 1963 (Crustacea: Decapoda: Scyllaridae)

The only specimen listed in the original description of Scyllarides deceptor Holthuis, 1963 is the holotype from São Paulo, Brazil, presently housed in the Leiden Museum. From the original description, however, it is clear that the new species was actually based on a number of additional specimens. Six of them exist in the collections of the Museum of Zoology in São Paulo, and are shown herein to be paratypes of S. deceptor. Scyllarides deceptor and S. brasiliensis Rathbun, 1906, continue to be confounded with one another, in consequence of their very similar color patterns and locally sympatric distributions. As many as 251,786 tons of slipper lobsters have been landed in Santa Catarina between 2000 and 2007. These catches have been attributed to S. deceptor alone and did not take into consideration the existence of a second species in the area, S. brasiliensis. Correct recognition of slipper-lobster species will be critical to properly evaluate the lobster stocks in southeastern Brazil. An opportunity is taken herein to elaborate on the taxonomy of S. deceptor and S. brasiliensis.

On the type material of Scyllarides deceptor Holthuis, 1963 (Crustacea: Decapoda: Scyllaridae)

The only specimen listed in the original description of Scyllarides deceptor Holthuis, 1963 is the holotype from São Paulo, Brazil, presently housed in the Leiden Museum. From the original description, however, it is clear that the new species was actually based on a number of additional specimens. Six of them exist in the collections of the Museum of Zoology in São Paulo, and are shown herein to be paratypes of S. deceptor. Scyllarides deceptor and S. brasiliensis Rathbun, 1906, continue to be confounded with one another, in consequence of their very similar color patterns and locally sympatric distributions. As many as 251,786 tons of slipper lobsters have been landed in Santa Catarina between 2000 and 2007. These catches have been attributed to S. deceptor alone and did not take into consideration the existence of a second species in the area, S. brasiliensis. Correct recognition of slipper-lobster species will be critical to properly evaluate the lobster stocks in southeastern Brazil. An opportunity is taken herein to elaborate on the taxonomy of S. deceptor and S. brasiliensis.

Niche differences between two sympatric whiptail lizards (Cnemidophorus abaetensis and C. ocellifer, Teiidae) in the restinga habitat of northeastern Brazil

Differences among sympatric lizard species usually result from differences in the use of three resources: space, time and food or some combination of these three. However, differences in resource utilization among sympatric species may simply reflect their specific ecological needs rather than competitive pressures. In this study, we analyzed the temporal, spatial and food niche of two congeneric teiids (Cnemidophorus abaetensis and C. ocellifer) living sympatrically in the "restinga" habitat of Abaeté in the Salvador Municipality, Bahia State, Brazil to assess the degree of niche differentiation among them. The whiptail species overlapped considerably in an hourly activity (Ojk = 0.93), in microhabitat use (Ojk = 0.97) and in the prey items consumed (Ojk = 0.89). Differences in amount of vegetation in the microhabitats used by both lizard species may have contributed to differences in the activity period and in the distribution of the main prey eaten by these lizards which may, in turn, facilitate their coexistence in Abaeté. Although sympatric C. ocellifer and C. abaetensis in Abaeté differed only slightly in their use of microhabitats, period of activity and diet, the most important niche dimension segregating the two species seemed to be the food niche.

As diferenças entre espécies simpátricas geralmente podem ser atribuídas às variações na utilização de três dimensões primárias de recurso: o período de atividade, o microhabitat e o alimento ou a alguma combinação das três. No entanto, tais diferenças na utilização de recursos entre espécies simpátricas têm sido sugeridas mais como um reflexo de suas necessidades ecológicas específicas do que resultado de pressão competitiva. Neste estudo, avaliou-se o nicho temporal, o espacial e o alimentar de dois teídeos cogenéricos (Cnemidophorus abaetensis e C. ocellifer) vivendo em simpatria na restinga de Abaeté em Salvador, Bahia. As duas espécies de lagartos sobrepõem-se consideravelmente no período de atividade (Ojk = 0,93), no uso dos microhabitats (Ojk = 0,97) e nos tipos de presas consumidas (Ojk = 0,89). As diferenças na quantidade de vegetação nos microhabitats utilizadas pelas duas espécies podem ter contribuído para as diferenças no período de atividade e na distribuição dos principais tipos de presas consumidas por estas duas espécies de lagartos, o que pode ter favorecido a coexistência entre elas na restinga do Abaeté. No entanto, as diferenças na dieta são as mais significativas para a segregação.

Niche differences between two sympatric whiptail lizards (Cnemidophorus abaetensis and C. ocellifer, Teiidae) in the restinga habitat of northeastern Brazil

Differences among sympatric lizard species usually result from differences in the use of three resources: space, time and food or some combination of these three. However, differences in resource utilization among sympatric species may simply reflect their specific ecological needs rather than competitive pressures. In this study, we analyzed the temporal, spatial and food niche of two congeneric teiids (Cnemidophorus abaetensis and C. ocellifer) living sympatrically in the "restinga" habitat of Abaeté in the Salvador Municipality, Bahia State, Brazil to assess the degree of niche differentiation among them. The whiptail species overlapped considerably in an hourly activity (Ojk = 0.93), in microhabitat use (Ojk = 0.97) and in the prey items consumed (Ojk = 0.89). Differences in amount of vegetation in the microhabitats used by both lizard species may have contributed to differences in the activity period and in the distribution of the main prey eaten by these lizards which may, in turn, facilitate their coexistence in Abaeté. Although sympatric C. ocellifer and C. abaetensis in Abaeté differed only slightly in their use of microhabitats, period of activity and diet, the most important niche dimension segregating the two species seemed to be the food niche.

As diferenças entre espécies simpátricas geralmente podem ser atribuídas às variações na utilização de três dimensões primárias de recurso: o período de atividade, o microhabitat e o alimento ou a alguma combinação das três. No entanto, tais diferenças na utilização de recursos entre espécies simpátricas têm sido sugeridas mais como um reflexo de suas necessidades ecológicas específicas do que resultado de pressão competitiva. Neste estudo, avaliou-se o nicho temporal, o espacial e o alimentar de dois teídeos cogenéricos (Cnemidophorus abaetensis e C. ocellifer) vivendo em simpatria na restinga de Abaeté em Salvador, Bahia. As duas espécies de lagartos sobrepõem-se consideravelmente no período de atividade (Ojk = 0,93), no uso dos microhabitats (Ojk = 0,97) e nos tipos de presas consumidas (Ojk = 0,89). As diferenças na quantidade de vegetação nos microhabitats utilizadas pelas duas espécies podem ter contribuído para as diferenças no período de atividade e na distribuição dos principais tipos de presas consumidas por estas duas espécies de lagartos, o que pode ter favorecido a coexistência entre elas na restinga do Abaeté. No entanto, as diferenças na dieta são as mais significativas para a segregação.

Diet and microhabitat use by two Hylodinae species (Anura, Cycloramphidae) living in sympatry and syntopy in a Brazilian Atlantic Rainforest area

We analyzed the diet and microhabitat use for two Hylodinae anurans (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 and Crossodactylus gaudichaudii Duméril & Bibron, 1841, living in sympatry at an Atlantic Rainforest area of Ilha Grande, in southeastern Brazil. The two species live syntopically at some rocky streams. The two species differed strongly in microhabitat use. Hylodes phyllodes occurred mainly on rocks, whereas C. gaudichaudii was observed mostly on the water. Regarding diet, coleopterans, hymenopterans (ants), and larvae were the most important prey item consumed by both species. Data suggest that microhabitat use appears to be an important parameter differentiating these frogs with respect to general resource utilization.

Nós analisamos a dieta e o uso do microhabitat em duas espécies de anuros da subfamília Hylodinae (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 e Crossodactylus gaudichaudii Duméril & Bibron, 1841, que vivem em simpatria em uma área de Mata Atlântica na Ilha Grande, na região sudeste do Brasil. As duas espécies vivem sintopicamente em alguns riachos pedregosos. As duas espécies diferiram fortemente no uso do microhabitat. Hylodes phyllodes ocorreu principalmente sobre pedras, enquanto C. gaudichaudii foi observado na maioria das vezes dentro d'água. Com relação à dieta, coleópteros, himenópteros (formigas), e larvas foram as presas mais consumidas por ambas as espécies. Os dados sugerem que o uso do microhabitat parece ser um importante parâmetro diferenciando esses anuros com respeito a utilização de recursos.

Diet and microhabitat use by two Hylodinae species (Anura, Cycloramphidae) living in sympatry and syntopy in a Brazilian Atlantic Rainforest area

We analyzed the diet and microhabitat use for two Hylodinae anurans (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 and Crossodactylus gaudichaudii Duméril & Bibron, 1841, living in sympatry at an Atlantic Rainforest area of Ilha Grande, in southeastern Brazil. The two species live syntopically at some rocky streams. The two species differed strongly in microhabitat use. Hylodes phyllodes occurred mainly on rocks, whereas C. gaudichaudii was observed mostly on the water. Regarding diet, coleopterans, hymenopterans (ants), and larvae were the most important prey item consumed by both species. Data suggest that microhabitat use appears to be an important parameter differentiating these frogs with respect to general resource utilization.

Nós analisamos a dieta e o uso do microhabitat em duas espécies de anuros da subfamília Hylodinae (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 e Crossodactylus gaudichaudii Duméril & Bibron, 1841, que vivem em simpatria em uma área de Mata Atlântica na Ilha Grande, na região sudeste do Brasil. As duas espécies vivem sintopicamente em alguns riachos pedregosos. As duas espécies diferiram fortemente no uso do microhabitat. Hylodes phyllodes ocorreu principalmente sobre pedras, enquanto C. gaudichaudii foi observado na maioria das vezes dentro d'água. Com relação à dieta, coleópteros, himenópteros (formigas), e larvas foram as presas mais consumidas por ambas as espécies. Os dados sugerem que o uso do microhabitat parece ser um importante parâmetro diferenciando esses anuros com respeito a utilização de recursos.

Astyanax aff. fasciatus Cuvier, 1819 (Teleostei; Characidae): evidences of a species complex in the upper rio Tibagi basin (Paraná, Brazil)

Four populations of Astyanax aff. fasciatus of the upper rio Tibagi (municipal district of Ponta Grossa, Paraná State, Brazil), had their karyotypes and morphometry analyzed. The cytogenetic data show the occurrence of distinct karyotypes (cytotypes), here named cytotype A, with 2n=48 chromosomes (6m+18sm+14st+10a), cytotype B, with 2n=50 chromosomes (8m+18sm+14st+10a) and cytotype C, with 2n=50 chromosomes (8m+18sm+14st+10a). The distribution pattern of the constitutive heterochromatin was very similar between cytotypes A and B, but diverged in relation to cytotype C. Distinct cytotypes may occur in sympatry in the upper rio Tibagi region, with the exception of the Furna 2 sample, which presents cytotype A exclusively. In addition, a specimen with 2n=49 chromosomes (7m+18sm+14st+10a) was also found and, by the characteristics presented, may be a consequence of a rare hybridization event between cytotypes A and B. The morphometric analyses of canonical variates indicate a consistent isolation of the Furna 2 sample, while the other samples seem to be superimposed, indicating a possible gene flow or even a recent isolation event. This model points to a probable complex of cryptic species in the studied region.

Quatro populações de Astyanax aff. fasciatus do alto rio Tibagi (município de Ponta Grossa, Paraná, Brasil) foram citogeneticamente e morfometricamente analisadas. Os dados citogenéticos mostram a ocorrência de distintos cariótipos (citótipos), aqui nomeados citótipo A, com 2n=48 (6m+18sm+14st+10a), citótipo B, com 2n=50 (8m+18sm+14st+10a) e citótipo C, com 2n=50 cromossomos (8m+18sm+14st+10a). O padrão de distribuição da heterocromatina constitutiva foi muito similar entre os citótipos A e B, mas mostrou-se divergente em relação ao citótipo C. Citótipos distintos podem ocorrer em simpatria na região do alto rio Tibagi, com exceção da amostra da Furna 2, a qual apresenta somente o citótipo A exclusivamente. Além disso, um exemplar com 2n=49 cromoossomos (7m+18sm+14st+10a) foi também encontrado e, pelas características apresentadas, pode ser uma conseqüência de um raro evento de hibridização entre os citótipos A e B. As análises morfométricas de variáveis canônicas indicam um isolamento consistente da amostra da Furna 2 enquanto as demais amostras analisadas se apresentam sobrepostas indicando um possível fluxo gênico ou evento de isolamento recente. Este modelo aponta para um complexo de espécies crípticas na região estudada.

Astyanax aff. fasciatus Cuvier, 1819 (Teleostei; Characidae): evidences of a species complex in the upper rio Tibagi basin (Paraná, Brazil)

Four populations of Astyanax aff. fasciatus of the upper rio Tibagi (municipal district of Ponta Grossa, Paraná State, Brazil), had their karyotypes and morphometry analyzed. The cytogenetic data show the occurrence of distinct karyotypes (cytotypes), here named cytotype A, with 2n=48 chromosomes (6m+18sm+14st+10a), cytotype B, with 2n=50 chromosomes (8m+18sm+14st+10a) and cytotype C, with 2n=50 chromosomes (8m+18sm+14st+10a). The distribution pattern of the constitutive heterochromatin was very similar between cytotypes A and B, but diverged in relation to cytotype C. Distinct cytotypes may occur in sympatry in the upper rio Tibagi region, with the exception of the Furna 2 sample, which presents cytotype A exclusively. In addition, a specimen with 2n=49 chromosomes (7m+18sm+14st+10a) was also found and, by the characteristics presented, may be a consequence of a rare hybridization event between cytotypes A and B. The morphometric analyses of canonical variates indicate a consistent isolation of the Furna 2 sample, while the other samples seem to be superimposed, indicating a possible gene flow or even a recent isolation event. This model points to a probable complex of cryptic species in the studied region.

Quatro populações de Astyanax aff. fasciatus do alto rio Tibagi (município de Ponta Grossa, Paraná, Brasil) foram citogeneticamente e morfometricamente analisadas. Os dados citogenéticos mostram a ocorrência de distintos cariótipos (citótipos), aqui nomeados citótipo A, com 2n=48 (6m+18sm+14st+10a), citótipo B, com 2n=50 (8m+18sm+14st+10a) e citótipo C, com 2n=50 cromossomos (8m+18sm+14st+10a). O padrão de distribuição da heterocromatina constitutiva foi muito similar entre os citótipos A e B, mas mostrou-se divergente em relação ao citótipo C. Citótipos distintos podem ocorrer em simpatria na região do alto rio Tibagi, com exceção da amostra da Furna 2, a qual apresenta somente o citótipo A exclusivamente. Além disso, um exemplar com 2n=49 cromoossomos (7m+18sm+14st+10a) foi também encontrado e, pelas características apresentadas, pode ser uma conseqüência de um raro evento de hibridização entre os citótipos A e B. As análises morfométricas de variáveis canônicas indicam um isolamento consistente da amostra da Furna 2 enquanto as demais amostras analisadas se apresentam sobrepostas indicando um possível fluxo gênico ou evento de isolamento recente. Este modelo aponta para um complexo de espécies crípticas na região estudada.

Cytogenetics of two sympatric Corydoras species (pisces, siluriformes, challichtyidae) of Southern Brazil

Karyotypic data are presented for two sympatric Corydoras species of the Lagoa Dourada, namely, C. ehrhadti and C. paleatus, which are found in the upper Tibagi river basin (Ponta Grossa, State of Paraná, Brazil). The same diploid number and karyotypic formula were observed in both species/populations. A great similarity in the constitutive heterochromatin distribution and in the activity of nucleolar organizer regions was also found. The use of in situ hybridization with a fluorescent 18S rDNA probe allowed for the identification of the species/populations through the location of ribosomal sites.

Dados cariotípicos são apresentados para duas espécies simpátricas de Corydoras da Lagoa Dourada, C. ehrhadti e C. paleatus, pertencentes à bacia do alto Rio Tibagi (Ponta Grossa, Paraná, Brasil). O mesmo número diplóide e fórmula cariotípica foram observados em ambas espécies/populações. Grande similaridade foi verificada também para a distribuição da heterocromatina constitutiva e atividade das regiões organizadoras de nucléolos. O emprego da hibridação in situ com sonda fluorescente de DNAr 18S possibilitou identificar as espécies/populações por meio da localização dos sítios ribossomais.