RESUMO

The acoustic adaptation hypothesis (AAH) and ecological character displacement (ECD) are two potential mechanisms shaping call evolution that can predict opposite trends for the differentiation of signals. Under AAH, signals evolve to minimize environmental degradation and maximize detection against background noise, predicting call homogenization in similar habitats due to environmental constraints on signals. In contrast, ECD predicts greater differences in call traits of closely related taxa in sympatry because of selection against acoustic interference. We used comparative phylogenetic analyses to test the strength of these two selective mechanisms on the evolution of advertisement calls in glassfrogs, a highly diverse family of neotropical anurans. We found that, overall, acoustic adaptation to the environment may outweigh effects of species interactions. As expected under the AAH, temporal call parameters are correlated with vegetation density, but spectral call parameters had an unexpected inverse correlation with vegetation density, as well as an unexpected correlation with temperature. We detected call convergence among co-occurring species and also across multiple populations from the same species in different glassfrogs communities. Our results indicate that call convergence is common in glassfrogs, likely due to habitat filtering, while character displacement is relatively rare, suggesting that costs of signal similarity among related species may not drive divergent selection in all systems.

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Abstract Vocalizations are an important trait for the identification of cryptic and/or closely related amphibian species. Different vocalizations also contribute to partitioning of the acoustic space by sympatric species. This study aimed to describe the advertisement calls of anurans in a pond of the municipality of Floriano, State of Piauí, Brazil, and infer the acoustic niche partitioning of amphibians. Euclidean distance was used in a cluster analysis approach to infer the acoustic similarities among species. Thirteen species were analysed: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps and Scinax ruber. From these, six showed more than 90% of acoustic overlap: P. nattereri , P. cuvieri, L. fuscus and L. vastus (Leptodactylidae); and, D. nanus and D. rubicundulus (Hylidae). Despite the acoustic similarities among these six species, the acoustic interference was reduced due to the small number of sympatric species and to distinct features on carrier frequency such as dominant frequency and the degree of modulation in the frequency. Environmental factors limit the periods and sites of reproduction respectively, which may maintain the low anuran diversity and consequently reduce acoustic overlap.

Resumo A vocalização é um componente importante na identificação de espécies crípticas e/ou proximamente relacionadas de anfíbios anuros. Diferenças na bioacústica também contribuem para o particionamento do espaço acústico entre espécies simpátricas. Este estudo descreve o canto de anúncio de anuros em uma lagoa temporária do município de Floriano, Estado do Piauí, Brasil, além de buscar inferir o particionamento do nicho acústico entre essas espécies. Para tanto, foi utilizada a distância Euclidiana para compor uma análise de conglomerados e avaliar a similaridade/dissimilaridade da bioacústica da anurofauna. Treze espécies foram amostradas: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps e Scinax ruber. Destas, seis apresentaram mais de 90% de sobreposição acústica: P. nattereri, P. cuvieri, L. fuscus e L. vastus (Leptodactylidae); e, D. nanus e D. rubicundulus (Hylidae). Apesar da similaridade acústica entre essas seis espécies, a interferência é reduzida devido ao pequeno número de espécies simpátricas e certas características distintas na frequência do canto, tais como: frequência dominante e sua modulação. Fatores ambientais específicos do semiárido limitam os períodos e sítios reprodutivos, o que mantém baixa diversidade de espécies e consequentemente reduz a sobreposição no nicho acústico.

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We describe a new species of nurse-frog (Aromobatidae, Allobates) from Floresta Nacional de Carajás, southeastern Brazilian Amazonia. Allobates carajas sp. nov. is distinguished from similar congeneric species by the combination of the following characters: body-size range (snout-to-vent length 16.5-19.1 mm), dorsal color pattern with a dark brown hourglass-shaped mark, by the absence of a pale dorsolateral stripe and presence of a pale ventrolateral stripe, absence of a pale paracloacal mark, by overall bright yellow ventral colors of live male and female specimens, and by the posterior labium of tadpoles, with a single row of pyramidal papillae medially. The advertisement call of the new species is highly variable, with four possible temporal arrangements of notes (continuous emission of notes separated by regular silent intervals, continuous emission of notes separated by irregular silent intervals, emission of discrete note trills, and sporadic emission of single notes). Duration of notes range between 0.020-0.060 s, and the dominant frequency of notes range from 4.75 to 5.38 kHz. The new species is currently known only from forested habitats within Floresta Nacional de Carajás.

Assuntos

RESUMO

Vocalizations are an important trait for the identification of cryptic and/or closely related amphibian species. Different vocalizations also contribute to partitioning of the acoustic space by sympatric species. This study aimed to describe the advertisement calls of anurans in a pond of the municipality of Floriano, State of Piauí, Brazil, and infer the acoustic niche partitioning of amphibians. Euclidean distance was used in a cluster analysis approach to infer the acoustic similarities among species. Thirteen species were analysed: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps and Scinax ruber. From these, six showed more than 90% of acoustic overlap: P. nattereri , P. cuvieri, L. fuscus and L. vastus (Leptodactylidae); and, D. nanus and D. rubicundulus (Hylidae). Despite the acoustic similarities among these six species, the acoustic interference was reduced due to the small number of sympatric species and to distinct features on carrier frequency such as dominant frequency and the degree of modulation in the frequency. Environmental factors limit the periods and sites of reproduction respectively, which may maintain the low anuran diversity and consequently reduce acoustic overlap.(AU)

A vocalização é um componente importante na identificação de espécies crípticas e/ou proximamente relacionadas de anfíbios anuros. Diferenças na bioacústica também contribuem para o particionamento do espaço acústico entre espécies simpátricas. Este estudo descreve o canto de anúncio de anuros em uma lagoa temporária do município de Floriano, Estado do Piauí, Brasil, além de buscar inferir o particionamento do nicho acústico entre essas espécies. Para tanto, foi utilizada a distância Euclidiana para compor uma análise de conglomerados e avaliar a similaridade/dissimilaridade da bioacústica da anurofauna. Treze espécies foram amostradas: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps e Scinax ruber. Destas, seis apresentaram mais de 90% de sobreposição acústica: P. nattereri, P. cuvieri, L. fuscus e L. vastus (Leptodactylidae); e, D. nanus e D. rubicundulus (Hylidae). Apesar da similaridade acústica entre essas seis espécies, a interferência é reduzida devido ao pequeno número de espécies simpátricas e certas características distintas na frequência do canto, tais como: frequência dominante e sua modulação. Fatores ambientais específicos do semiárido limitam os períodos e sítios reprodutivos, o que mantém baixa diversidade de espécies e consequentemente reduz a sobreposição no nicho acústico.(AU)

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We describe a new species of nurse-frog (Aromobatidae, Allobates) from northwestern Brazilian Amazon. Allobates juami sp. nov. is distinguished from similar congeneric species by the combination of the following characters: body-size range (snout-to-vent length 17.5-18.5 mm), lack of dark pigments on ventral surfaces of male specimens, dorsal color pattern (predominantly solid dark brown, but conspicuously light brown over snout and urostyle regions), presence of conspicuous pale dorsolateral and ventrolateral stripes, and presence of a diffuse pale paracloacal mark. The advertisement call of the new species lasts 2.5-5.1 s, contains 60-73 short notes (trills), and is emitted at an average rate of 13 notes per second within trills. Duration of silent intervals between notes ranges between 0.020-0.050 s, and the peak frequency of notes ranges from 4.59 to 5.47 kHz. The new species is currently known only from the type locality at Estação Ecológica Juami-Japurá (1.96455° S, 67.93579° W; ~ 87 m a.s.l.).

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Data on geographic distribution and ecology are essential when defining the conservation status of aspecies. Herein, we present new information about the geographic distribution, habitat and advertisement callof Ischnocnema henselii, an endemic species of the southern Atlantic Forest. We conducted this study in forestfragments in the state of Santa Catarina, Southern Brazil, from January 2008 to November 2012. We recordedI. henselii in eight fragments over 100 ha in size, both inside and outside conservation units. We often observedless than 20 males in calling activity. The calling activity was daytime and nighttime, and more intense in therain. We observed individuals perched on vegetation, on leaves or branches, on the leaf litter or under treetrunks. Duration of advertisement calls ranged from 14.71 ± 1.68 s (n = 11 calls) and interval between noteswas 0.22 ± 0.13 s (n = 99 notes). We observed that the advertisement calls had a feature that we call “alternatingmodulation” in the amplitude of the notes. We suggest that further bioacoustic studies should analyze therelevance of this alternating modulation, to understand its role in communication. Although I. henselii is a habitatspecialist, it is currently considered a common species, classified as Least Concern by Brazilian and IUCNlists. In the region studied, characterized by small and isolated remnants of the Atlantic Forest, I. henselii is notan abundant species and its spatial distribution is always associated with wet forest fragments. The increasingdegradation of forest remnants in this region causes microclimatic and structural changes that may compromisethe permanence of strictly forest and moisture-dependent species for reproduction, such as I. henselii.(AU)

Informações sobre distribuição geográfica e ecologiasão essenciais para a definição do estado de conservação de uma espécie. Aqui, nós apresentamos novasinformações sobre a distribuição geográfica, habitat e canto de anúncio de I. henselii, um anfíbio endêmicodo Sul da Mata Atlântica. Nós conduzimos o estudo em fragmentos florestais no estado de Santa Catarina, sul do Brasil, de janeiro de 2008 a novembro de 2012. Registramos I. henselii em oito fragmentos com tamanhoacima de 100 ha, no interior ou fora de unidades de conservação. Nós frequentemente observamos menosde 20 machos em atividade de vocalização. As atividades de vocalização foram registradas de dia e à noite eeram mais intensas sob chuva. Observamos indivíduos empoleirados na vegetação, sobre folhas ou galhos, nofolhiço ou sob troncos de árvores caídas. A duração do canto de anúncio foi 14,71s ± 1,68 (n = 11 cantos) e ointervalo entre as notas foi de 0,22s ± 0,13 (n = 99 notas). Os cantos de anúncio apresentaram o que chamamosde “modulação alternada” na amplitude das notas. Sugerimos que outros estudos analisem a relevânciadesta “modulação alternada”, visando compreender a sua relação com a comunicação nesta espécie. EmboraI. henselli seja especialista de habitat, é considerada comum, classificada na categoria “preocupação menor”nas listas brasileira e mundial de espécies ameaçadas de extinção. Na região de estudo, caracterizada porremanescentes pequenos e isolados de Mata Atlântica, I. henselii é pouco abundante e encontrada somenteem fragmentos florestais úmidos. A crescente degradação dos remanescentes florestais nesta região ocasionamudanças microclimáticas e estruturais que podem comprometer a permanência de espécies estritamenteflorestais e dependentes da umidade para reprodução, como I. henselii.(AU)

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RESUMO

Data on geographic distribution and ecology are essential when defining the conservation status of aspecies. Herein, we present new information about the geographic distribution, habitat and advertisement callof Ischnocnema henselii, an endemic species of the southern Atlantic Forest. We conducted this study in forestfragments in the state of Santa Catarina, Southern Brazil, from January 2008 to November 2012. We recordedI. henselii in eight fragments over 100 ha in size, both inside and outside conservation units. We often observedless than 20 males in calling activity. The calling activity was daytime and nighttime, and more intense in therain. We observed individuals perched on vegetation, on leaves or branches, on the leaf litter or under treetrunks. Duration of advertisement calls ranged from 14.71 ± 1.68 s (n = 11 calls) and interval between noteswas 0.22 ± 0.13 s (n = 99 notes). We observed that the advertisement calls had a feature that we call “alternatingmodulation” in the amplitude of the notes. We suggest that further bioacoustic studies should analyze therelevance of this alternating modulation, to understand its role in communication. Although I. henselii is a habitatspecialist, it is currently considered a common species, classified as Least Concern by Brazilian and IUCNlists. In the region studied, characterized by small and isolated remnants of the Atlantic Forest, I. henselii is notan abundant species and its spatial distribution is always associated with wet forest fragments. The increasingdegradation of forest remnants in this region causes microclimatic and structural changes that may compromisethe permanence of strictly forest and moisture-dependent species for reproduction, such as I. henselii.

Informações sobre distribuição geográfica e ecologiasão essenciais para a definição do estado de conservação de uma espécie. Aqui, nós apresentamos novasinformações sobre a distribuição geográfica, habitat e canto de anúncio de I. henselii, um anfíbio endêmicodo Sul da Mata Atlântica. Nós conduzimos o estudo em fragmentos florestais no estado de Santa Catarina, sul do Brasil, de janeiro de 2008 a novembro de 2012. Registramos I. henselii em oito fragmentos com tamanhoacima de 100 ha, no interior ou fora de unidades de conservação. Nós frequentemente observamos menosde 20 machos em atividade de vocalização. As atividades de vocalização foram registradas de dia e à noite eeram mais intensas sob chuva. Observamos indivíduos empoleirados na vegetação, sobre folhas ou galhos, nofolhiço ou sob troncos de árvores caídas. A duração do canto de anúncio foi 14,71s ± 1,68 (n = 11 cantos) e ointervalo entre as notas foi de 0,22s ± 0,13 (n = 99 notas). Os cantos de anúncio apresentaram o que chamamosde “modulação alternada” na amplitude das notas. Sugerimos que outros estudos analisem a relevânciadesta “modulação alternada”, visando compreender a sua relação com a comunicação nesta espécie. EmboraI. henselli seja especialista de habitat, é considerada comum, classificada na categoria “preocupação menor”nas listas brasileira e mundial de espécies ameaçadas de extinção. Na região de estudo, caracterizada porremanescentes pequenos e isolados de Mata Atlântica, I. henselii é pouco abundante e encontrada somenteem fragmentos florestais úmidos. A crescente degradação dos remanescentes florestais nesta região ocasionamudanças microclimáticas e estruturais que podem comprometer a permanência de espécies estritamenteflorestais e dependentes da umidade para reprodução, como I. henselii.

Assuntos

RESUMO

Abstract Vocalizations are an important trait for the identification of cryptic and/or closely related amphibian species. Different vocalizations also contribute to partitioning of the acoustic space by sympatric species. This study aimed to describe the advertisement calls of anurans in a pond of the municipality of Floriano, State of Piauí, Brazil, and infer the acoustic niche partitioning of amphibians. Euclidean distance was used in a cluster analysis approach to infer the acoustic similarities among species. Thirteen species were analysed: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps and Scinax ruber. From these, six showed more than 90% of acoustic overlap: P. nattereri , P. cuvieri, L. fuscus and L. vastus (Leptodactylidae); and, D. nanus and D. rubicundulus (Hylidae). Despite the acoustic similarities among these six species, the acoustic interference was reduced due to the small number of sympatric species and to distinct features on carrier frequency such as dominant frequency and the degree of modulation in the frequency. Environmental factors limit the periods and sites of reproduction respectively, which may maintain the low anuran diversity and consequently reduce acoustic overlap.

Resumo A vocalização é um componente importante na identificação de espécies crípticas e/ou proximamente relacionadas de anfíbios anuros. Diferenças na bioacústica também contribuem para o particionamento do espaço acústico entre espécies simpátricas. Este estudo descreve o canto de anúncio de anuros em uma lagoa temporária do município de Floriano, Estado do Piauí, Brasil, além de buscar inferir o particionamento do nicho acústico entre essas espécies. Para tanto, foi utilizada a distância Euclidiana para compor uma análise de conglomerados e avaliar a similaridade/dissimilaridade da bioacústica da anurofauna. Treze espécies foram amostradas: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps e Scinax ruber. Destas, seis apresentaram mais de 90% de sobreposição acústica: P. nattereri, P. cuvieri, L. fuscus e L. vastus (Leptodactylidae); e, D. nanus e D. rubicundulus (Hylidae). Apesar da similaridade acústica entre essas seis espécies, a interferência é reduzida devido ao pequeno número de espécies simpátricas e certas características distintas na frequência do canto, tais como: frequência dominante e sua modulação. Fatores ambientais específicos do semiárido limitam os períodos e sítios reprodutivos, o que mantém baixa diversidade de espécies e consequentemente reduz a sobreposição no nicho acústico.

RESUMO

Abstract Vocalizations are an important trait for the identification of cryptic and/or closely related amphibian species. Different vocalizations also contribute to partitioning of the acoustic space by sympatric species. This study aimed to describe the advertisement calls of anurans in a pond of the municipality of Floriano, State of Piauí, Brazil, and infer the acoustic niche partitioning of amphibians. Euclidean distance was used in a cluster analysis approach to infer the acoustic similarities among species. Thirteen species were analysed: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps and Scinax ruber. From these, six showed more than 90% of acoustic overlap: P. nattereri , P. cuvieri, L. fuscus and L. vastus (Leptodactylidae); and, D. nanus and D. rubicundulus (Hylidae). Despite the acoustic similarities among these six species, the acoustic interference was reduced due to the small number of sympatric species and to distinct features on carrier frequency such as dominant frequency and the degree of modulation in the frequency. Environmental factors limit the periods and sites of reproduction respectively, which may maintain the low anuran diversity and consequently reduce acoustic overlap.

Resumo A vocalização é um componente importante na identificação de espécies crípticas e/ou proximamente relacionadas de anfíbios anuros. Diferenças na bioacústica também contribuem para o particionamento do espaço acústico entre espécies simpátricas. Este estudo descreve o canto de anúncio de anuros em uma lagoa temporária do município de Floriano, Estado do Piauí, Brasil, além de buscar inferir o particionamento do nicho acústico entre essas espécies. Para tanto, foi utilizada a distância Euclidiana para compor uma análise de conglomerados e avaliar a similaridade/dissimilaridade da bioacústica da anurofauna. Treze espécies foram amostradas: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps e Scinax ruber. Destas, seis apresentaram mais de 90% de sobreposição acústica: P. nattereri, P. cuvieri, L. fuscus e L. vastus (Leptodactylidae); e, D. nanus e D. rubicundulus (Hylidae). Apesar da similaridade acústica entre essas seis espécies, a interferência é reduzida devido ao pequeno número de espécies simpátricas e certas características distintas na frequência do canto, tais como: frequência dominante e sua modulação. Fatores ambientais específicos do semiárido limitam os períodos e sítios reprodutivos, o que mantém baixa diversidade de espécies e consequentemente reduz a sobreposição no nicho acústico.

RESUMO

The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk.

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RESUMO

ABSTRACT The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk.

RESUMO

The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk.(AU)

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Estudios acerca de la diversidad e historia natural de comunidades de anuros son elementales para distinguir entre fluctuaciones naturales de aquellas causadas por impactos antrópicos (herramienta clave en programas de conservación), evaluar el papel que juegan en la dinámica de los ecosistemas y permitir comparaciones de gradientes de diversidad. En este contexto, se analiza la diversidad, la distribución temporal y espacial, y los turnos de vocalización de anuros de tres sitios de reproducción en los Esteros del Iberá, en el nordeste de Argentina. Los muestreos fueron mensuales entre julio de 2008 y junio de 2010. Se registraron 26 especies pertenecientes a cinco familias: Bufonidae (2), Hylidae (11), Leptodactylidae (11), Microhylidae (1), y Odontophrynidae (1). Se encontraron variaciones en la riqueza de especies por sitio, en el periodo, frecuencia y turno de vocalización y en la abundancia de machos vocalizadores. La riqueza es similar al de otros humedales similares, incluyendo un importante dominio de leptodactílidos e hílidos, patrón frecuente en ensambles neotropicales. La concentración de las especies en actividad de vocalización en los meses más cálidos y lluviosos estuvo asociada con los cambios en la temperatura y en las precipitaciones, las cuales fueron señaladas como algunos de los factores que inician la actividad reproductiva en ambientes estacionales.(AU)

Studies on diversity and natural history of anuran communities are basic to distinguish natural fluctuations from those due to human impacts (a key tool in conservation programs), to assess the role they play in ecosystems dynamics and to allow comparison of diversity gradients. With those objectives, this paper analyzes diversity, temporal and spatial distribution, and calling daily time of the anurans from three breeding sites at Esteros del Iberá, in northeastern Argentina. Samples were taken monthly, between July 2008 and June 2010. We recorded 26 species belonging to five families: Bufonidae (2), Hylidae (11), Leptodactylidae (11), Microhylidae (1) and Odontophrynidae (1). The study highlights variations in species richness per site, in the period, frequency and calling daily time and in the densities of calling males. The species richness is comparable to that of other similar wetlands, including the dominance of leptodactylids and hylid, a frequent pattern in Neotropical assemblages. The concentration of active species in the warmest and wettest months was associated with changes in temperature and rainfall, which were identified as important factors that initiate reproductive activity in seasonal environments.(AU)

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RESUMO

Estudios acerca de la diversidad e historia natural de comunidades de anuros son elementales para distinguir entre fluctuaciones naturales de aquellas causadas por impactos antrópicos (herramienta clave en programas de conservación), evaluar el papel que juegan en la dinámica de los ecosistemas y permitir comparaciones de gradientes de diversidad. En este contexto, se analiza la diversidad, la distribución temporal y espacial, y los turnos de vocalización de anuros de tres sitios de reproducción en los Esteros del Iberá, en el nordeste de Argentina. Los muestreos fueron mensuales entre julio de 2008 y junio de 2010. Se registraron 26 especies pertenecientes a cinco familias: Bufonidae (2), Hylidae (11), Leptodactylidae (11), Microhylidae (1), y Odontophrynidae (1). Se encontraron variaciones en la riqueza de especies por sitio, en el periodo, frecuencia y turno de vocalización y en la abundancia de machos vocalizadores. La riqueza es similar al de otros humedales similares, incluyendo un importante dominio de leptodactílidos e hílidos, patrón frecuente en ensambles neotropicales. La concentración de las especies en actividad de vocalización en los meses más cálidos y lluviosos estuvo asociada con los cambios en la temperatura y en las precipitaciones, las cuales fueron señaladas como algunos de los factores que inician la actividad reproductiva en ambientes estacionales.

Studies on diversity and natural history of anuran communities are basic to distinguish natural fluctuations from those due to human impacts (a key tool in conservation programs), to assess the role they play in ecosystems dynamics and to allow comparison of diversity gradients. With those objectives, this paper analyzes diversity, temporal and spatial distribution, and calling daily time of the anurans from three breeding sites at Esteros del Iberá, in northeastern Argentina. Samples were taken monthly, between July 2008 and June 2010. We recorded 26 species belonging to five families: Bufonidae (2), Hylidae (11), Leptodactylidae (11), Microhylidae (1) and Odontophrynidae (1). The study highlights variations in species richness per site, in the period, frequency and calling daily time and in the densities of calling males. The species richness is comparable to that of other similar wetlands, including the dominance of leptodactylids and hylid, a frequent pattern in Neotropical assemblages. The concentration of active species in the warmest and wettest months was associated with changes in temperature and rainfall, which were identified as important factors that initiate reproductive activity in seasonal environments.

Assuntos

RESUMO

Populations of species occupying large geographic ranges are often phenotypically diverse as a consequence of variation in selective pressures and drift. This applies to attributes involved in mate choice, particularly when both geographic range and breeding biology overlap between related species. This condition may lead to interference of mating signals, which would in turn promote reproductive character displacement (RCD). We investigated whether variation in the advertisement call of the mountain treefrog (Hyla eximia) is linked to geographic distribution with respect to major Mexican river basins (Panuco, Lerma, Balsas and Magdalena), or to coexistence with its sister (the canyon treefrog, Hyla arenicolor) or another related species (the dwarf treefrog, Tlalocohyla smithii). We also evaluated whether call divergence across the main river basins could be linked to genetic structure. We found that the multidimensional acoustic space of calls from two basins where H. eximia currently interacts with T. smithii, was different from the acoustic space of calls from H. eximia elsewhere. Individuals from these two basins were also distinguishable from the rest by both the phylogeny inferred from mitochondrial sequences, and the genetic structure inferred from nuclear markers. The discordant divergence of H. eximia advertisement calls in the two separate basins where its geographic range overlaps that of T. smithii can be interpreted as the result of two independent events of RCD, presumably as a consequence of acoustic interference in the breeding choruses, although more data are required to evaluate this possibility.

RESUMO

We present a new phylogeny, based on DNA sequences of mitochondrial and nuclear genes, for frogs of the genus Osteocephalus with emphasis in the Osteocephalus buckleyi species complex. Genetic, morphologic, and advertisement call data are combined to define species boundaries and describe new species. The phylogeny shows strong support for: (1) a basal position of Osteocephalus taurinus + Osteocephalus oophagus, (2) a clade containing phytotelmata breeding species, and (3) a clade that corresponds to the Osteocephalus buckleyi species complex. Our results document a large proportion of hidden diversity within a set of populations that were previously treated as a single, widely distributed species, Osteocephalus buckleyi. Individuals assignable to Osteocephalus buckleyi formed a paraphyletic group relative to Osteocephalus verruciger and Osteocephalus cabrerai and contained four species, one of which is Osteocephalus buckleyisensu stricto and three are new. Two of the new species are shared between Ecuador and Peru (Osteocephalus vilmaesp. n. and Osteocephalus cannatellaisp. n.) and one is distributed in the Amazon region of southern Peru (Osteocephalus germanisp. n.) We discuss the difficulties of using morphological characters to define species boundaries and propose a hypothesis to explain them.