Daniel Loebmann

From Amazonia to the Atlantic forest: molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges.

Documenting the Neotropical amphibian diversity has become a major challenge facing the threat of global climate change and the pace of environmental alteration. Recent molecular phylogenetic studies have revealed that the actual number of species in South American tropical forests is largely underestimated, but also that many lineages are millions of years old. The genera Phyzelaphryne (1 sp.) and Adelophryne (6 spp.), which compose the subfamily Phyzelaphryninae, include poorly documented, secretive, and minute frogs with an unusual distribution pattern that encompasses the biotic disjunction between Amazonia and the Atlantic forest. We generated >5.8 kb sequence data from six markers for all seven nominal species of the subfamily as well as for newly discovered populations in order to (1) test the monophyly of Phyzelaphryninae, Adelophryne and Phyzelaphryne, (2) estimate species diversity within the subfamily, and (3) investigate their historical biogeography and diversification. Phylogenetic reconstruction confirmed the monophyly of each group and revealed deep subdivisions within Adelophryne and Phyzelaphryne, with three major clades in Adelophryne located in northern Amazonia, northern Atlantic forest and southern Atlantic forest. Our results suggest that the actual number of species in Phyzelaphryninae is, at least, twice the currently recognized species diversity, with almost every geographically isolated population representing an anciently divergent candidate species. Such results highlight the challenges for conservation, especially in the northern Atlantic forest where it is still degraded at a fast pace. Molecular dating revealed that Phyzelaphryninae originated in Amazonia and dispersed during early Miocene to the Atlantic forest. The two Atlantic forest clades of Adelophryne started to diversify some 7 Ma minimum, while the northern Amazonian Adelophryne diversified much earlier, some 13 Ma minimum. This striking biogeographic pattern coincides with major events that have shaped the face of the South American continent, as we know it today.

Amphibians and reptiles from a highly diverse area of the Caatinga domain: composition and conservation implications

A herpetofauna do Complexo do Planalto da Ibiapaba (CPI), CE, Brasil, foi estudada durante dois anos, usando cinco metodos de amostragem e informacao disponivel na literatura. Os anfibios estavam representados por 38 especies distribuidos em nove familias. Os repteis encontrados somaram 84 especies, distribuidos em 25 familias. A maioria dos anfibios coletados apresentou ampla ocorrencia ao longo do CPI, sendo 24 especies (63,2%) ocorrendo em pelo menos 60% dos ambientes amostrados. Repteis tiveram um padrao diferente uma vez que 52 especies (62.6%) tiveram uma distribuicao restrita (ate dois ambientes). Dezesseis das 25 especies consideradas como rara no CPI sao restritas as areas de floresta umida relictuais. Foi aplicado um indice de raridade/vulnerabilidade para determinar as especies mais susceptiveis. Pristimantis sp., Adelophryne baturitensis Hoogmoed, Borges, and Cascon, 1994, Pseudopaludicola sp. (aff. saltica), Scinax fuscomarginatus (A. Lutz, 1925) e Odontophrynus carvalhoi Savage & Cei, 1965 foram os anfibios mais vulneraveis no CPI. Repteis mostraram uma variacao mais diversa na escala de raridade com 40 especies consideradas vulneraveis. Entre os repteis vulneraveis Leposoma baturitensis Rodrigues & Borges, 1997, Bothrops sp. (gr. atrox), Atractus ronnie Passos, Fernandes & Borges-Nojosa, 2007, Apostolepis sp. (gr. pimy) e Mesoclemmys perplexa Bour & Zaher, 2005 foram as especies mais raras na encontradas ao longo do Complexo do Planalto da Ibiapaba. Os resultados indicam que aproximadamente 70% dos repteis encontrados no Ceara estao presentes nesse complexo. O CPI e tambem a area do Bioma Caatinga com a maior riqueza de especies, incluindo especies raras e ameacadas.

Amphibians of the state of Piauí, Northeastern Brazil: a preliminary assessment

The state of Piaui is located between the Caatinga and Cerrado biomes in Northeastern Brazil, having a rich heterogeneity of habitats. However, publications regarding the amphibians of this state are scarce. We compiled literature data and complemented it with amphibian inventories in some municipalities of Piaui and present a list of 55 species (54 anurans and one caecilian). Ten of them are endemic to the Cerrado biome (Rhinella veredas, R. cerradensis, R. mirandaribeiroi, R. rubescens, Dendropsophus rubicundulus, Phyllomeduza azurea, Leptodactylus pustulatus, Eupemphix nattereri, Physalaemus centralis, and Proceratophrys goyana) and two endemic to the Caatinga (Rhinella jimi and Ceratophrys joazeirensis). We also present data about species richness of 18 sampled municipalities, species distribution patterns, and conservation status.

The activity patterns and microhabitat use of Pseudis minuta Günther, 1858 (Anura, Hylidae) in the Lagoa do Peixe National Park, a biosphere reserve of the brazilian subtropics

Pseudis minuta is abundant in a variety of aquatic environments of the Pampa domain. Therefore, it can be considered a good model for testing hypotheses on environmental heterogeneity and the influence of climate on the activity of anurans. In this study, we examined the spatial distribution pattern of P. minuta in terms of microhabitats and the influence of abiotic factors on seasonal fluctuations in the abundance of this species. Samples were collected monthly from April 2008 to May 2009 in wetlands and coastal dunes in the Lagoa do Peixe National Park. A total of 112 specimens of P. minuta were collected, of which 45 were found in the wetland area and 67 in the dune area. The species showed seasonal fluctuation in abundance, and it was most abundant in months with higher temperatures (spring-summer). Pseudis minuta was mainly associated with aquatic vegetation, an expected pattern in terms of their morphological adaptations to this environment. Among the abiotic parameters analyzed, only the monthly mean temperature showed a significant correlation (p < 0.05; r = 0.67) with the abundance of P. minuta. We concluded that P. minuta is a generalist species with respect to microhabitat use and also that fluctuation in its population abundance is mainly associated with seasonal variation in temperature.

Feeding ecology and basal food sources that sustain the Paradoxal frog Pseudis minuta: a multiple approach combining stomach content, prey availability, and stable isotopes

In the present study, we investigated ontogenetic diet shifts, feeding strategy, prey preferences, and basal food sources that sustain the Paradoxal frog (Pseudis minuta) based on stomach content, prey availability, and stable isotope (δ13C, δ15N) approaches. The feeding strategy analysis showed that the population can be considered a generalist species with each individual displaying a marked opportunism for different preys. Trophic positions estimated using nitrogen isotopic ratio (δ15N) revealed that tadpoles are primary consumers, but post-metamorphic individuals shifted to secondary and tertiary trophic levels as they increase in body size. A stable isotopic mixing model revealed that most of the carbon (0.61–0.72) sustaining the post-metamorphic P. minuta is derived from the aquatic rather than the adjacent terrestrial environment. This finding suggests that the post-metamorphic P. minuta is strongly dependent on carbon sources that primarily originate in aquatic systems, regardless of the terrestrial or aquatic origins of the arthropods in its diet. Our results indicated that this species is a generalist-opportunistic predator that derives most of their carbon sources from the aquatic environment where it shows preference for aquatic preys with higher individual biomasses.

Does human influence on coastal grasslands habitats affect predation pressure on snakes

The loss and modification of habitats by humans have been considered key factors in the decline of diversity of species worldwide. However, the real effect caused by these disturbances on the biota is still poorly understood. The assessment of the changes in the network of interspecific interactions, such as predation rates on the native fauna, can be an important tool to diagnose the functionality of disturbed ecosystems. In this study we evaluate the predation rate on snakes in coastal grasslands in South America under human influence. Predation rate of artificial snakes, unlike that obtained in other studies, was lower in human-altered areas than preserved ones. Our findings may be due to a reduction in the abundance and/or richness of species of native predators in more disturbed areas.

The recognition of Dendropsophus minusculus (Rivero, 1971) (Hylidae, Dendropsophini) as a highly polymorphic, multi-domain distributed species.

Herein we present new occurrences of sites of Dendropsophus minusculus in Brazil adding information about reproductive biology and colour patterns of the species. Such information is fundamental for characterising the species that we believe has been neglected due to its morphological similarity with other congeneric species. Dendropsophus minusculus may be found in different morphoclimatic domains, being one of the most generalist species of the genus in this aspect. The species plasticity is not restricted to its occurrence, but also related to aspects of its reproductive biology, and we hypothesised that the latter feature could explain the wide geographical range of the species. We highlight the importance of further in-depth studies and the use of D. minusculus as a model to understand the historical events responsible for the current geographical distribution of the morphoclimatic domains in Brazil.

What the largest tadpole feeds on? A detailed analysis of the diet composition of Pseudis minuta tadpoles (Hylidae, Dendropsophini)

We analyzed the diet of 25 individuals of Pseudis minuta tadpoles which consisted in debris with more than 30%, follow by diatoms, euglenids, green algae, and desmids. With regard to the feeding strategy, P. minuta tadpoles are generalist consumer. The negative correlation between the abundance of items in the digestive tract and the mouth width indicate an effect of metamorphosis on the diet.

Trophic Ecology of Two Sympatric Frogs with Contrasting Morphology and Habitat Use in a Subtropical Wetland

Abstract Frog diets are influenced by multiple factors, including morphological constraints, habitat use, and seasonal variation in environmental conditions and food availability. This study combined stomach content analysis (SCA), stable isotope analysis (SIA), and estimates of prey availability to investigate the influence of body size and microhabitat use on seasonal variation of the trophic ecology of two sympatric hylids (Pseudis minuta and Scinax squalirostris). We evaluated two hypotheses: (1) the species with larger body and mouth sizes or broader use of microhabitats will have greater diet breadth, and (2) regardless of differences in morphological traits and microhabitat use, diet breadth of both species will be greater during the warmer of two periods. Pseudis minuta exhibited larger body size and mouth width and revealed broader use of microhabitats (mostly within and near major water bodies), whereas S. squalirostris had smaller body size and mouth gape and was found exclusively within or near phytotelmata (plant-held water bodies). SCA revealed that P. minuta had a more diverse diet than S. squalirostris. Only P. minuta showed temporal dietary differences, but these findings did not corroborate our prediction of greater diet diversity during the warmer and drier period when prey densities were higher. The two species had distinct carbon and nitrogen stable isotope ratios, indicating assimilation of different resources, except during the colder wetter season when their isotope spaces overlapped partially. We concluded that the two hylids did not use the same food resources on account of their differences in morphology and microhabitat use, and environmental seasonality did not influence their feeding strategies.

Phylogeography of the critically endangered neotropical annual fish, Austrolebias wolterstorffi (Cyprinodontiformes: Aplocheilidae): genetic and morphometric evidence of a new species complex

Austrolebias wolterstorffi is a critically endangered annual fish, occurring in temporary ponds in a restricted area of Southern Brazil and Uruguay. Here, we evaluate the levels of genetic diversity and morphometric differentiation presented by A. wolterstorffi, attempting to reconstruct the spatiotemporal scenario by which this species reached their current distribution. Part of the mitochondrial cytochrome b and nuclear rhodopsin genes were characterized and analysed for a set of 122 and 110 specimens, respectively, collected along the entire distribution range of the species. Additionally, shape variations were evaluated for 92 individuals (43 males and 49 females) through geometric morphometric methods. Our analyses demonstrated several cases of significantly high levels of genetic differentiation among individual populations, in an isolation-by-distance pattern of divergence, with at least six different population groups along the Patos-Mirim lagoon. These groups differed by a minimum of 0.9% and a maximum of 2.6% of corrected cyt b nucleotide distances and did not share any mitochondrial haplotype. Such a pattern, added to the slight morphometric differentiation detected for most of the groups, suggests the occurrence of incipient speciation as consequence of allopatric fragmentation. The chronophylogenetic tree performed with the concatenated dataset supported independent oriental and occidental colonization routes, with the population located in the northwest part of the Rio Grande do Sul coastal plain presenting the most ancient divergence. In general, the recovered biogeographic patterns are highly consistent with the records of Quaternary climatic changes and depositional events that have occurred along the area inhabited by the studied species. This allowed us to establish a molecular clock calibration system for Neotropical annual fish. Thus, although the taxonomic status of each of the detected population units needs further study, it is clear that independent conservation strategies must be taken in each of the major areas covered by this study, most of which are located in Brazil.