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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.

The composition and diversity of animal-associated microbial communities are shaped by multiple ecological and evolutionary processes acting at different spatial and temporal scales. Skin microbiomes are thought to be strongly influenced by the environment due to the direct interaction of the host’s skin with the external media. As expected, the diversity of amphibian skin microbiomes is shaped by climate and host habitats, whereas phylogenetic effects appear to be weak. However, the relative strength of phylogenetic and environmental effects on amphibian skin microbiomes remains poorly understood. Here, we analysed sequence data from 1,091 adult salamanders in 41 species to characterise and compare the diversity and composition of skin bacteria. We assessed the relative contribution of climate, host habitat, and host phylogeny to the observed patterns of bacterial diversity. We found that microbial alpha was mainly associated with host habitat and climate, but that microbial beta diversity was more strongly associated with host taxonomy and phylogeny. This phylogeny effect predominantly occurred at intermediate levels of host divergence (0–50 Mya). Our results support the importance of environmental factors shaping the diversity of amphibian skin microbiomes, but also support host phylogenetic history as a major factor shaping these microbial communities.

The skin microbiome in amphibians has gained a lot of attention as some of its members play a protective role against pathogens such as the fungus Batrachochytrium dendrobatidis (Bd). The composition of skin bacterial communities has been suggested as one of the factors explaining differences in susceptibility to Bd among amphibian species and populations. The boreal toad Anaxyrus boreas is known to be susceptible to Bd, and severe population declines in its southeastern range have been documented. However, throughout A. boreas distribution, populations present differences in susceptibility to Bd infections which may be associated with differences in skin microbial diversity. This study compared the skin bacterial diversity and Bd infection levels of A. boreas in one desert population and one pine forest population from Baja California, Mexico. We found that desert and pine forest toad populations exhibit differences in skin bacterial community structure but show similar Bd infection levels. Using a predictive method, we found that the abundance of bacteria with potential Bd-inhibitory properties differed between uninfected and infected individuals but not between populations. Our data suggest that several bacteria in the skin community may be offering protection from Bd infections in these A. boreas populations. This study provides foundational evidence for future studies seeking to understand the skin-microbial variation among boreal toads’ populations and its relation with Bd susceptibility.

The recent emergence of the pathogen

Batrachochytrium salamandrivorans (Bsal), a species related to the destructive pathogen Batrachochytrium dendrobatidis (Bd), was found and identified in Europe in 2013. Now, a decade later, a large amount of information is available. This includes data from studies in the field, reports of infection in captive amphibians, laboratory studies testing host susceptibility, and data from prospective studies that test for Bsal’s presence in a location. We conducted a systematic review of the published literature and compiled a dataset of Bsal tests. We identified 67 species that have been reported positive for Bsal, 20 of which have a threatened conservation status. The distribution of species that have been found with infection encompasses 69 countries, highlighting the potential threat that Bsal poses. We point out where surveillance to detect Bsal have taken place and highlight areas that have not been well monitored. The large number of host species belonging to the families Plethodontidae and Salamandridae suggests a taxonomic pattern of susceptibility. Our results provide insight into the risk posed by Bsal and identifies vulnerable species and areas where surveillance is needed to fill existing knowledge gaps.

Host microbial communities are increasingly seen as an important component of host health. In amphibians, the first land vertebrates that are threatened by a fungal skin disease globally, our understanding of the factors influencing the microbiome of amphibian skin remains incomplete because recent studies have focused almost exclusively on bacteria, and little information exists on fungal communities associated with wild amphibian species. In this study, we describe the effects of host phylogeny, climate, geographic distance, and infection with a fungal pathogen on the composition and structure of bacterial and fungal communities in seven tropical salamander species that occur in the Trans-Mexican Volcanic Belt of Central Mexico. We find that host phylogenetic relatedness is correlated with bacterial community composition while a composite climatic variable of temperature seasonality and precipitation is significantly associated with fungal community composition. We also estimated co-occurrence networks for bacterial and fungal taxa and found differences in the degree of connectivity and the distribution of negative associations between the two networks. Our results suggest that different factors may be responsible for structuring the bacterial and fungal communities of amphibian skin and that the inclusion of fungi in future studies could shed light on important functional interactions within the microbiome.

The skin microbiome in amphibians has gained a lot of attention as some of its members play a protective role against pathogens such as the fungus Batrachochytrium dendrobatidis (Bd). The composition of skin bacterial communities has been suggested as one of the factors explaining differences in susceptibility to Bd among amphibian species and populations. The boreal toad Anaxyrus boreas is known to be susceptible to Bd, and severe population declines in its southeastern range have been documented. However, throughout A. boreas distribution, populations present differences in susceptibility to Bd infections which may be associated with differences in skin microbial diversity. This study compared the skin bacterial diversity and Bd infection levels of A. boreas in one desert population and one pine forest population from Baja California, Mexico. We found that desert and pine forest toad populations exhibit differences in skin bacterial community structure but show similar Bd infection levels. Using a predictive method, we found that the abundance of bacteria with potential Bd-inhibitory properties differed between uninfected and infected individuals but not between populations. Our data suggest that several bacteria in the skin community may be offering protection from Bd infections in these A. boreas populations. This study provides foundational evidence for future studies seeking to understand the skin-microbial variation among boreal toads' populations and its relation with Bd susceptibility.

We assessed the effect of temperature on subclinical Batrachochytrium dendrobatidis (Bd) infection in three species of plethodontids. Collected individuals were tested for Bd in the field during the dry and rainy season and randomly assigned to 15° and 18°C treatments for 30 days. We collected 129 salamanders, of these nine individuals tested positive for Bd in the field. At the two temperature trials, 12 individuals that were Bd-negative in the field, tested positive for Bd. Near the end of the temperature trials, 18 of 21 Bd-positive individuals tested negative for Bd. Three individuals that were Bd positive in the field and assigned to the 18°C trial died during the experiment. Our results suggest that at 15°C the most of plethodontids present subclinical infection, whereas at higher temperatures, Bd infection can increase to detectable levels. The processes underlying plethodontids’s recovery from Bd infection warrants further study.

Skin-associated bacteria are known to inhibit infection by the fungal pathogen Batrachochytrium dendrobatidis (Bd) in amphibians. It has also been postulated that skin-associated bacterial community is related to Bd infection intensity. However, our understanding of host microbial dynamics and their importance in regulating Bd intensity is limited. We analyzed Bd infection and skin-associated bacteria from two amphibian species, the salamander Ambystoma rivulare and the frog Lithobates spectabilis that co-occurred in a tropical high-altitude site in central Mexico. Sixty-three percent of sampled salamander individuals and 80% of frog individuals tested positive for Bd. Overall, we registered 622 skin-associated bacterial genera, from which 73 are known to have Bd inhibitory effects. These inhibitory taxa represented a relative abundance of 50% in relation to total relative bacterial abundance. Our results indicated that, although sharing some bacterial taxa, bacterial community from the skin of both species was different in taxonomic composition and in relative abundance. Pseudomonas spp. and Stenotrophomonas spp. were among the five most abundant bacterial taxa of both species. Both bacterial taxa inhibit Bd infection. We detected that bacterial richness and relative abundance of inhibitory Bd bacteria were negatively related to intensity of Bd infection independent of species and seasons. Despite the high Bd prevalence in both host species, no dead or sick individuals were registered during field surveys. The relatively low levels of Bd load apparently do not compromise survival of host species. Therefore, our results suggested that individuals analyzed were able to survive and thrive under a dynamic relation with enzootic infections of Bd and their microbiota.

The North American tiger salamander species complex, including its best-known species, the Mexican axolotl, has long been a source of biological fascination. The complex exhibits a wide range of variation in developmental life history strategies, including populations and individuals that undergo metamorphosis, those able to forego metamorphosis and retain a larval, aquatic lifestyle (i.e., paedomorphosis), and those that do both. This life history variation has been assumed to lead to reproductive isolation and speciation, but the degree to which it has shaped population- and species-level divergence is poorly understood. Using a large multi-locus dataset from hundreds of samples across North America, we identified genetic clusters across the geographic range of the tiger salamander complex. These clusters often contain a mixture of paedomorphic and metamorphic taxa, indicating that geographic isolation has played a larger role in lineage divergence than paedomorphosis in this system. This conclusion is bolstered by geography-informed analyses indicating no effect of life history strategy on population genetic differentiation and by model-based analyses demonstrating gene flow between adjacent metamorphic and paedomorphic populations. This fine-scale genetic perspective on life-history variation establishes a framework for understanding how plasticity, local adaptation, and gene flow contribute to lineage divergence. Many members of the tiger salamander complex are endangered, and the Mexican axolotl is an important model system in regenerative and biomedical research. Our results chart a course for more informed use of these taxa in experimental, ecological, and conservation research.SignificanceStatementPopulation structure and speciation are shaped by a combination of biotic and abiotic factors. The tiger salamander complex has been considered to be a key group where life history variation has led to a rapid rate of speciation, driven in large part by the evolution of obligate paedomorphosis–a condition where adults maintain an aquatic, larval phenotype. Using a large multi-locus dataset, we present evidence of gene flow between taxa with different life history strategies, suggesting that obligate paedomorphosis is not a strong driver of speciation in the tiger salamander complex. Many of these nominal taxa are listed as critically endangered, and our genetic results provide information and guidance that will be useful for their conservation.

Microbial symbionts are increasingly recognized as playing a critical role in organismal health across a wide range of hosts. Amphibians are unique hosts in that their skin helps to regulate the exchange of water, ions, and gases, and it plays an active role in defense against pathogens through the synthesis of anti-microbial peptides. The microbiome of amphibian skin includes a diverse community of bacteria known to defend against pathogens, including the global pandemic lineage of Batrachochytrium dendrobatidis associated with mass amphibian die-offs. The relative influence of host phylogeny and environment in determining the composition of the amphibian skin microbiome remains poorly understood. We collected skin swabs from montane amphibians in Mexico and Guatemala, focusing on two genera of plethodontid salamanders and one genus of frogs. We used high throughput sequencing to characterize the skin bacterial microbiome and tested the impact of phylogeny and habitat on bacterial diversity. Our results show that phylogenetic history strongly influences the diversity and community structure of the total bacterial microbiome at higher taxonomic levels (between orders), but on lower scales (within genera and species), the effect of habitat predominates. These results add to a growing consensus that habitat exerts a strong effect on microbiome structure and composition, particularly at shallow phylogenetic scales.

Lambert et al . question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species.

The genusChiropterotritonis endemic to Mexico with a geographical distribution along the Sierra Madre Oriental, the Trans Mexican Volcanic Belt and the Sierra de Juárez. The recent use of molecular tools has shown that Mexico’s amphibian diversity is highly underestimated, including a large number of cryptic, unnamed species.Chiropterotritonhas 18 described species including terrestrial, arboreal and cave-dwelling species. In previous molecular studies, the presence of multiple undescribed species was evident. We present a phylogenetic hypothesis based on mitochondrial data, which includes all described species and six undescribed taxa. Based on the morphological analyses and, when available, combined with molecular data, we describe five new species of the genus;Chiropterotriton casasisp. nov.,C. ceronorumsp. nov.,C. meliponasp. nov.,C. perotensissp. nov. andC. totonacussp. nov. In addition, we redescribe two others:Chiropterotriton chiropterusandC. orculus, and provide a comparable account of one additional sympatric congener. This increases the number of species in the genus to 23, which represent a considerable component of Mexican plethodontid richness.

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), is an infectious disease of amphibians linked to mass amphibian die-offs worldwide. In this study, we sampled four dead and dying individuals of Ambystoma altamirani and Lithobates montezumae to detect the presence of Bd and Bsal. By real-time PCR (qPCR) and histopathology methods, we found the presence of Bd and the absence of Bsal in all individuals sampled. Our study indicates that chytridiomycosis may act as a threat for these species and highlight that future surveys are urgently needed to evaluate the Bd infection on populations of A. altamirani and L. montezumae.

Facultative or obligate paedomorphosis has evolved several times in Mexican populations of the salamander genus Ambystoma, leading to increased genetic divergence among populations with alternate life histories and contributing to population divergence in this species complex. In the present study, we surveyed the genetic diversity of Ambystoma populations in lakes of the Cuenca Oriental, a high elevation closed drainage basin that encompasses permanent crater lakes harbouring salamander populations. We genotyped individuals from five populations aiming to better understand population dynamics and the evolution of paedomorphosis in this system. Specifically, we tested the hypotheses that the evolution of paedomorphosis in Ambystoma taylori resulted in reduced genetic exchange with populations of Ambystoma velasci in neighbouring lakes. Second, we tested whether the populations in brackish lakes of the Cuenca Oriental, Lake Atexcac, and Lake Alchichica show restricted gene flow across the basin, possibly as a result of local adaptation to those microhabitats. Using various indices of population genetic diversity, Bayesian assignment, and approximate Bayesian computation methods, we show that genetic exchange between brackish lakes and freshwater lakes is negligible, despite continued gene flow among freshwater lakes. We show that the first divergence among populations occurred between Alchichica and the remaining populations and that the evolution of paedomorphosis in A. taylori was likely favoured by local adaptation to saline conditions, thus increasing its genetic isolation. An apparently similar process appears to be in progress independently in lake Atexcac, showing that local adaptation may play an important role in population isolation and, ultimately, in speciation.

"The first record about the pathogenic fungus Batrachochytrium dendrobatidis in Mexican plethodontid salamanders dates back to the 1970s. However, little is known of the patterns of infection in wild populations and the effects of changes in temperature on the degree of infection. This work quantified Bd infection in a population of Pseudoeurycea leprosa in La Malinche National Park, Puebla, Mexico from June 2011 to September 2012. A total of 160 adult salamanders were experimentally exposed to temperatures of 10, 15, 20, 23, 25, or 28 ◦C for 10 weeks. The results of this study revealed that: (1) the population of P. leprosa in La Malinche National Park is infected with Bd throughout the year at a low prevalence of between 0 and 17%; (2) 20.6% of the salamanders that were Bd negative at the time of collection expressed chytridiomycosis after exposure to the experimental temperature treatments; (3) temperature was the cause of death in each treatment, with temperatures of 25 ◦C and 28 ◦C affecting the survival of P. leprosa; (4) the infection load in certain P. leprosa individuals exhibited cycles of increasing and decreasing zoospore genomic equivalents over time. All Rights Reserved © 2016 Universidad Nacional Autónoma de México, Instituto de Biología. This is an open access item distributed under the Creative Commons CC License BY-NC-ND 4.0."

The complex geological history of Central America has been useful for understanding the processes influencing the distribution and diversity of multiple groups of organisms. Anurans are an excellent choice for such studies because they typically exhibit site fidelity and reduced movement. The objective of this work was to identify the impact of recognized geographic barriers on the genetic structure, phylogeographic patterns and divergence times of a wide-ranging amphibian species,Hyalinobatrachium fleischmanni. We amplified three mitochondrial regions, two coding (COI and ND1) and one ribosomal (16S), in samples collected from the coasts of Veracruz and Guerrero in Mexico to the humid forests of Chocó in Ecuador. We examined the biogeographic history of the species through spatial clustering analyses (Geneland and sPCA), Bayesian and maximum likelihood reconstructions, and spatiotemporal diffusion analysis. Our data suggest a Central American origin ofH. fleischmanniand two posterior independent dispersals towards North and South American regions. The first clade comprises individuals from Colombia, Ecuador, Panama and the sister speciesHyalinobatrachium tatayoi; this clade shows little structure, despite the presence of the Andes mountain range and the long distances between sampling sites. The second clade consists of individuals from Costa Rica, Nicaragua, and eastern Honduras with no apparent structure. The third clade includes individuals from western Honduras, Guatemala, and Mexico and displays deep population structure. Herein, we synthesize the impact of known geographic areas that act as barriers to glassfrog dispersal and demonstrated their effect of differentiatingH. fleischmanniinto three markedly isolated clades. The observed genetic structure is associated with an initial dispersal event from Central America followed by vicariance that likely occurred during the Pliocene. The southern samples are characterized by a very recent population expansion, likely related to sea-level and climatic oscillations during the Pleistocene, whereas the structure of the northern clade has probably been driven by dispersal through the Isthmus of Tehuantepec and isolation by the Motagua–Polochic–Jocotán fault system and the Mexican highlands.

A new species of Craugastor (Anura: Craugastoridae) from the montane rainforest of the Cordillera de Talamanca, Costa Rica. A new dirt frog of the Craugastor podiciferus Species Group is described from Costa Rica; it is restricted to elevations between 2330 and 2700 m a.s.l. in the montane rainforest of the Cordillera de Talamanca. Analysis of DNA sequences of the mitochondrial 16S rRNA (16S) and cytochrome oxidase I (COI) genes reveals a distinct lineage within the C. podiciferus Species Group. Additional morphological and morphometric analyses support the distinctiveness of this lineage that is described as a new species herein. The species is distinguished from other members of the C. podiciferus Species Group by its unique coloration: a violet-brown to blackish brown venter with white pigment forming blotches, and dark brown palmar surfaces with prominent white folds between subarticular tubercles in the adults. The genetic divergence of the species from other members of the C. podiciferus Species Group is signifcant (higher than 9.2% in 16S and 13.3% in COI). Although not closely related, it resembles C. podiciferus morphologically, a species that also inhabits montane rainforest. The discovery of this new species highlights the importance of montane rainforest as a center of species richness and endemism.

The recent decline in populations of European salamanders caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) has generated worldwide concern, as it is a major threat to amphibians. Evaluation of the areas most suitable for the establishment of Bsal combined with analysis of the distribution of salamander species could be used to generate and implement biosecurity measures and protect biodiversity at sites with high salamander diversity. In this study, we identified the areas most suitable for the establishment of Bsal in Mexico. Mexico has the second-highest salamander species diversity in the world; thus, we identified areas moderately to highly suitable for the establishment of Bsal with high salamander diversity as potential hotspots for surveillance. Central and Southern Mexico were identified as high-risk zones, with 13 hotspots where 30% of Mexican salamander species occur, including range-restricted species and endangered species. We propose that these hotspots should be thoroughly monitored for the presence of Bsal to prevent the spread of the pathogen if it is introduced to the country.

The demise of amphibians? Rapid spread of disease is a hazard in our interconnected world. The chytrid fungus Batrachochytrium dendrobatidis was identified in amphibian populations about 20 years ago and has caused death and species extinction at a global scale. Scheele et al. found that the fungus has caused declines in amphibian populations everywhere except at its origin in Asia (see the Perspective by Greenberg and Palen). A majority of species and populations are still experiencing decline, but there is evidence of limited recovery in some species. The analysis also suggests some conditions that predict resilience. Science , this issue p. 1459 ; see also p. 1386

Species recovery after forest disturbance is a highly studied topic in the tropics, but considerable debate remains on the role of secondary forests as biodiversity repositories, especially regarding the functional and phylogenetic dimensions of biodiversity. Also, studies generally overlook how alpha and beta diversities interact to produce gamma diversity along successional gradients.We used a metacommunity approach to assess how species sorting (i.e., environmental filtering) and mass effect (i.e., source‐sink dynamics) affect 14 complementary metrics of amphibian taxonomic, functional, and phylogenetic diversity along a successional gradient in southern Mexico. As amphibians have narrow environmental tolerances and low dispersal capabilities, we expected that species sorting may be relatively more important than mass effect in structuring amphibian communities.Between 2010 and 2012, we sampled frogs, salamanders, and caecilians in 23 communities distributed in four successional stages: young (2–5 years old) and intermediate (13–28 years old) secondary forests, old‐growth forest fragments, and old‐growth continuous forest. We assessed 15 ecologically relevant functional traits per species and used a time‐calibrated molecular phylogeny.We recorded 1,672 individuals belonging to 30 species and 11 families. Supporting our expectations from the species sorting perspective, from the poorest (younger forests) to the best quality (continuous forest) scenarios, we observed (a) an increase in alpha diversity regardless of species abundances; (b) a clear taxonomic segregation across successional stages; (c) an increase in functional richness and dispersion; (d) an increase in mean phylogenetic distance and nearest taxon index; and (e) a reduction in mean nearest taxon distance. However, 10 species occurred in all successional stages, resulting in relatively low beta diversity. This supports a mass effect, where interpatch migrations contribute to prevent local extinctions and increase compositional similarity at the regional scale.Our findings indicate that amphibian metacommunities along forest successional gradients are mainly structured by species sorting, but mass effects may also play a role if high levels of forest cover are conserved in the region. In fact, secondary forests and forest fragments can potentially safeguard different aspects of amphibian diversity, but their long‐term conservation value requires preventing additional deforestation.

Author(s): Rovito, SM; Parra-Olea, G; Recuero, E; Wake, DB | Abstract: The Neotropical bolitoglossine salamanders represent an impressive adaptive radiation, comprising roughly 40% of global salamander species diversity. Despite decades of morphological studies and molecular work, a robust multilocus phylogenetic hypothesis based on DNA sequence data is lacking for the group. We estimated species trees based on multilocus nuclear and mitochondrial data for all major lineages within the bolitoglossines, and used our new phylogenetic hypothesis to test traditional biogeographical scenarios and hypotheses of morphological evolution in the group. In contrast to previous phylogenies, our results place all Central American endemic genera in a single clade and suggest that Central America played a critical role in the early biogeographical history of the group. The large, predominantly Mexican genus Pseudoeurycea is paraphyletic, and analyses of the nuclear data place two lineages of Pseudoeurycea as the sister group of Bolitoglossa. Our phylogeny reveals extensive homoplasy in morphological characters, which may be the result of truncation or alteration of a shared developmental trajectory. We used our phylogenetic results to revise the taxonomy of the genus Pseudoeurycea.

Author(s): Rovito, SM; Vasquez-Almazan, CR; Papenfuss, TJ; Parra-Olea, G; Wake, DB | Abstract: The cloud forests of Mesoamerica are notable for their high endemism, and plethodontid salamanders provide a striking example of divergence and microendemism across cloud forest blocks at a regional level. Salamanders that make use of arboreal bromeliad microhabitats in the cloud forest appear to be especially prone to divergence driven by natural habitat fragmentation, and are expected to show high endemism at small spatial scales. We use a multilocus dataset to investigate the biogeographic history and relationships among species of a small genus of salamander, Cryptotriton, restricted to the cloud forests of Nuclear Central America. We use a morphological data set along with a coalescent species delimitation method to reveal the presence of at least one undescribed species from an isolated cloud forest in eastern Guatemala. Biogeographic analyses show that Cryptotriton has a different biogeographic history than another clade of cloud forest-restricted salamanders in the same region, perhaps indicating that each genus restricted the spatial expansion and diversification of the other through preemptive occupancy. Our results suggest that isolation across relatively short geographic distances has led to range fragmentation and deep divergence between species. Exploration of remaining patches of cloud forest likely will continue to reveal undetected diversity.

ResumenLa quitridiomicosis es una enfermedad causada por el hongo patógeno Batrachochytrium dendrobatidis (Bd), el cual afecta la piel de los anfibios y puede ABSprovocar la muerte. El declive de las poblaciones de anfibios como resultado del efecto de este patógeno se presentó simultáneamente en varias partes del mundo a partir de la década de 1980. En México se identificó una oleada epidémica por Bd en la década de 1970, la cual concuerda con el declive de poblaciones de salamandras (caudados) en el sur del país. Nuestro trabajo presenta una revisión sobre el estado actual del conocimiento de la quitridiomicosis como uno de los factores causales del declive de las poblaciones de anfibios a nivel mundial y se analiza la información recabada al momento sobre la presencia de este patógeno en México. A la fecha, se ha registrado la infección en 50 especies de anfibios que se distribuyen, principalmente en las regiones montañosas del centro y sur del país, y se ha determinado que las familias Hylidae y Plethodontidae son las más afectadas. Diversos autores han propuesto que el cambio climático global ha jugado un papel fundamental en la presencia y virulencia del género Batrachochytrium, ya que el incremento de temperatura induce un desequilibrio en la relación patógeno-hospedero provocando mayor virulencia de Bd y/o mayor susceptibilidad a la infección en los anfibios. Sobre este tema, analizamos las temperaturas registradas de 1964 a 1989 en las zonas donde el declive de caudados fue más drástico. No se encontró una asociación clara entre el declive de salamandras con la temperatura. Por otro lado, se determinó que al igual que otros países, el comercio internacional, la introducción y desplazamiento de la “rana toro” Lithobates catesbeiana son importantes para la dispersión del patógeno.AbstractChytridiomycosis is a disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which affects the skin of amphibians and may cause deathABS. The decline of amphibian populations as a result of the effect of this pathogen occurred simultaneously in various parts of the world from the early 1980's. In Mexico the epidemic wave of Bd was identified in the 1970's, which is consistent with the decline of salamander (caudate) populations in the southern part of the country. Our work presents a review of the state of knowledge of chytridiomycosis as a factor in the decline of amphibian populations worldwide and the information gathered until now of the presence of this pathogen in Mexico. To date, there has been infection in 50 Mexican amphibian species that are mainly distributed in the mountainous regions of central and southern Mexico, and was determined that the families Hylidae and Plethodontidae are the most affected. Several authors have suggested that global climate change has played a key role in the occurrence and virulence of Batrachochytrium because the temperature increase induces an imbalance in the pathogen-host relationship to increased virulence of Bd and/or increased susceptibility to infection in amphibians. On this matter, we analyzed the reported temperatures of 1964-1989 in areas where the decline of caudates was more drastic. We found no relationship between the decline of salamanders with temperature. However, the international trade, the introduction and displacement of the “bullfrog” Lithobates catesbeiana are important factors for the spread of the pathogen.

The small size and apparent external morphological similarity of the minute salamanders of the genus Thorius have long hindered evolutionary studies of the group. We estimate gene and species trees within the genus using mitochondrial and nuclear DNA from nearly all named and many candidate species and find three main clades. We use this phylogenetic hypothesis to examine patterns of morphological evolution and species coexistence across central and southern Mexico and to test alternative hypotheses of lineage divergence with and without ecomor- phological divergence. Sympatric species differ in body size more than expected after accounting for phylogenetic relationship, and morphological traits show no significant phylogenetic signal. Sympatric species tend to differ in a combination of body size, presence or absence of maxillary teeth, and relative limb or tail length, even when they are close relatives. Sister species of Thorius tend to occupy climatically similar environments, which suggests that divergence across climatic gradients does not drive species formation in the genus. Rather than being an example of cryptic species formation, Thorius more closely resembles an adaptive radiation, with ecomorphological divergence that is bounded by organism-level constraints. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 622-643. ADDITIONAL KEYWORDS: biogeography - diversification - morphology - phylogeny - species formation - systematics.

We describe three new species of minute salamanders, genus Thorius, from the Sierra Madre del Sur of Oaxaca, Mexico. Until now only a single species, T. minutissimus, has been reported from this region, although molecular data have long shown extensive genetic differentiation among geographically disjunct populations. Adult Thorius pinicola sp. nov., T. longicaudus sp. nov., and T. tlaxiacus sp. nov. are larger than T. minutissimus and possess elliptical rather than oval nostrils; T. pinicola and T. longicaudus also have longer tails. All three new species occur west of the range of T. minutissimus, which has the easternmost distribution of any member of the genus. The new species are distinguished from each other and from other named Thorius in Oaxaca by a combination of adult body size, external morphology and osteology, and by protein characters (allozymes) and differences in DNA sequences. In addition, we redescribe T. minutissimus and a related species, T. narisovalis, to further clarify the taxonomic status of Oaxacan populations and to facilitate future studies of the remaining genetically differentiated Thorius that cannot be satisfactorily assigned to any named species. Populations of all five species considered here appear to have declined dramatically over the last one or two decades and live specimens are difficult to find in nature. Thorius may be the most endangered genus of amphibians in the world. All species may go extinct before the end of this century.

The chytrid fungus Batrachochytrium dendrobatidis was detected in five populations of Pseudacris hypochondriaca curta, an endemic treefrog fully dependent on desert oases in Baja California Sur, Mexico. Prevalence of the fungus varied among oases with values of 8, 31, 42, 60, and 100% for populations sampled. Oases with higher prevalence were inhabited by exotic species such as American bullfrogs (Lithobates catesbeianus) and crayfish (Procambarus clarkii). These observations are the first of B. dendrobatidis in amphibians from lowland (

Aim Our goal was to reconstruct the phylogenetic history and historical demography of highly divergent populations of the endemic plethodontid salamander Pseudoeurycea leprosa, to elucidate the timing and mechanisms of divergence in the Trans-Volcanic Belt of Mexico. Location The Trans-Volcanic Belt (TVB) of central Mexico, including the states of Mexico, Morelos, Puebla, Tlaxcala and Veracruz. Methods We sequenced the cytochrome b mitochondrial DNA gene for 281 individuals from 26 populations and nine mountain ranges in the TVB, and used Bayesian phylogenetic reconstruction and Markov chain Monte Carlo coalescent methods to infer historical demographic parameters and divergences among populations in each mountain system. Results We found deep genetic divergences between eastern and central TVB mountain systems despite their recent volcanic origin. Populations of P. leprosa show a pattern of refugial populations in the north-eastern and eastern limits of the species’ distribution, and genetic evidence of rapid population expansion in mountain ranges of the central TVB. The oldest divergences among populations date to c. 3.8 Ma, and the most recent divergences in the central TVB are Pleistocene in age (c. 0.7 Ma). Main conclusions Given the timing and order of population diversification in P. leprosa, we conclude that early isolation in multiple habitat refuges in north-eastern and eastern mountain ranges played an important role in structuring population diversity in the TVB, followed by population expansion and genetic divergence of the central range populations. The dynamic climatic and volcanic changes in this landscape generally coincide with the history of intra-specific diversification in P. leprosa. Climate-driven changes in habitat distribution in an actively changing volcanic landscape have shaped divergences in the TVB and very likely contributed to the high levels of speciation and endemism in this biodiverse region.

Species with highly restricted distributions are vulnerable to extinction, and modification of natural habitats within their small ranges is a primary threat to their persistence. Expansion of urban development significantly impacts natural habitats and, therefore, threatens local diversity. The Mexican axolotl, Ambystoma mexicanum, is a strictly aquatic species that persists currently in two highly threatened and isolated populations. The current habitat remaining for these species are remnants of a historically extensive lacustrine system that occupied the entire Valley of Mexico, but has been destroyed by the growth of Mexico City. Unexpectedly, a third viable population of axolotls has been found in Chapultepec Park, a public recreational area in the heart of Mexico City. Phylogenetic and haplotype network analyses of mitochondrial DNA sequences confirmed low genetic differentiation and a recurrent lack of monophyly in many of the taxa belonging to the Ambystoma tigrinum species group, including A. me...

A lungworm of the genus Rhabdias (Nematoda: Rhabdiasidae) was recovered from Scinax staufferi (Anura: Hylidae) collected in Guadalupe Victoria Mapastepec, Chiapas, Mexico (15°28'28"N, 92°53'26"W, 102 m). Morphology of the nematode is briefly described and compared with other species of the genus, and mainly with parasites of hylids in the Neotropical Realm. This study represents the first record of a species of Rhabdias species parasitizing S. staufferi, and also constitutes the first record of a nematode parasite of hylid frogs in Chiapas State, Mexico.Un gusano pulmonar del género Rhabdias (Nematoda: Rhabdiasidae) fue recuperado de Scinax staufferi (Anura: Hylidae) recolectado en Guadalupe Victoria Mapastepec, Chiapas, México (15°28'28"N, 92°53'26"O, 102 m). La morfología del rhabdiásido se describe brevemente y se compara con otras especies del género y principalmente con aquellas parásitas de hílidos distribuidos en la región Neotropical. El presente estudio representa el primer registro de una especie de Rhabdias como parásito de S. staufferi, y también constituye el primer registro de un nematodo parásito en hílidos para el estado de Chiapas, México.

La revision de los ejemplares de la familia Meloidae de la pequena coleccion entomologica del ECOSUR en San Cristobal de las Casas (Chiapas, Mexico), acompanada del examen de material chiapaneco del genero Epicauta de la Coleccion Nacional de Insectos (CNIN-IBUNAM, Instituto de Biologia, UNAM, Mexico), material de Meloidae del Museo Hungaro de Historia Natural (HMNH, Magyar Termeszettudomanyi Muzeum, Budapest) y de la coleccion Marco A. Bologna (MAB, Universita degli Studi Roma Tre, Italia), permite documentar por primera vez la presencia en el Estado de Chiapas de: Epicauta diana Pinto, 1991; Epicauta rufipennis (Chevrolat, 1834); Epicauta forticornis (Haag-Rutenberg, 1880); Epicauta distorta (Champion, 1892); Meloe tropicus Motschulsky, 1856; Denierota kraatzi (Haag-Rutenberg, 1880); Pyrota decorata (Haag-Rutenberg, 1880); Cissites auriculata (Champion, 1892) y Tetraonyx frontalis Chevrolat, 1833. De entre estas especies destacan las citas de M. tropicus que permiten confirmar la presencia de la especie en Mexico y la de D. kraatzi que constituye el primer registro preciso del genero Denierota en Mexico. Por otra parte, la revision del material utilizado por Z. Kaszab en la descripcion del genero Denierota (HNHM), acompanado del material de la coleccion M. Bologna y el examen de fotografias detalladas de los tipos de los dos taxones incluidos en el genero Denierota, Lytta sanguineoguttata Haag-Rutenberg, 1880 y Lytta kraatzi Haag-Rutenberg, 1880, del Zoologische Staatssammlung de Munich (Alemania), nos permiten concluir que el genero Denierota incluye una unica especie descrita y nos permite formalizar la sinonimia de L. sanguineoguttata con L. kraatzi, resolviendo el largo y debatido problema taxonomico que suscitaba la identidad de L. kraatzi y el problema secundario de falta de localidad-tipo (�patria ignota�) para esta especie.

We document major declines of many species of salamanders at several sites in Central America and Mexico, with emphasis on the San Marcos region of Guatemala, one of the best studied and most diverse salamander communities in the Neotropics. Profound declines of several formerly abundant species, including 2 apparent extinctions, are revealed. Terrestrial microhabitat specialists at mid- to high elevations have declined more than microhabitat generalists. These terrestrial microhabitat specialists have largely disappeared from multiple sites in western Guatemala, including in well-protected areas, suggesting that the phenomenon cannot be explained solely by localized habitat destruction. Major declines in southern Mexican plethodontid salamanders occurred in the late 1970s to early 1980s, concurrent with or preceding many reported frog declines. The species in decline comprise several major evolutionary lineages of tropical salamanders, underscoring that significant portions of the phylogenetic diversity of Neotropical salamanders are at risk. Our results highlight the urgent need to document and understand Neotropical salamander declines as part of the larger effort to conserve global amphibian diversity.

94 páginas., [ES] Se presenta un catálogo taxonómico de los representantes mexicanos de la familia Meloidae que incluye un listado revisado de sinonimias, localidades típicas y registros geográficos publicados de cada una de las especies. La fauna mexicana incluye en la actualidad 255 especies vivientes y una fósil, distribuidas en 21 géneros de las subfamilias Meloinae, Nemognathinae y Tetraonycinae. En el último catálogo general, Blackwelder (1945) recogió la presencia en México de 160 especies de esta familia, casi 100 especies menos de las que se conocen en la actualidad y sin embargo, la cifra actual parece encontrarse aún lejos de la real, ya que existen muchas especies ampliamente distribuidas al norte de la frontera con los Estados Unidos cuya presencia es muy probable en territorio mexicano. En cuanto a la taxonomía y nomenclatura de las especies, en este catálogo se propone el uso de los nombres Epicauta dugesi Werner, 1957 y Tegrodera erosa extincta Beauregard, 1890; se incluyen tres sinonimias nuevas de Nemognatha chrysomeloides (Linnaeus, 1763) (N. atra Beauregard, 1890; N. pallidicollis Beauregard, 1890 y N. violacea Beauregard, 1890) y otra de E. dugesi (Epicauta tamara Adams & Selander, 1979); se designa lectotipo para Lytta koltzei var. minor Haag-Rutenberg, 1880 con el propósito de solucionar el problema taxonómico generado tras la designación inválida de lectotipo de L. k. var. cyanescens; y finalmente se consideran como especies posiblemente a excluir del listado de Meloidae de México a Cissites maculata (Swederus, 1787) y Tetraonyx (Tetraonyx) bimaculatus (Klug, 1825)., [EN] A comprehensive taxonomic catalogue of the Mexican representatives of the family Meloidae is presented. The catalogue includes a revised synonymical list including type localities and published geographical records for all known species. The Mexican Fauna of Meloidae currently includes 255 extant species, plus one only known from the fossil conrecord, arranged in 21 genera within the subfamilies Meloinae, Nemognathinae and Tetraonycinae. The last comprehensive catalogue published (Blackwelder, 1945) recorded the presence of 160 species of Meloidae in México, almost 100 species less than the current known number. However the current number of species seems to be far below the actual number, since many species widely distributed along the northern border, within the United States, are likely to be found also in Mexico. Regarding taxonomic and nomenclatural changes, in this catalogue we propose the use of the names Epicauta dugesi Werner, 1957 and Tegrodera erosa extincta Beauregard, 1890; we propose three new synonymies for Nemognatha chrysomeloides (Linnaeus, 1763) (N. atra Beauregard, 1890; N. pallidicollis Beauregard, 1890 and N. violacea Beauregard, 1890) and one for E. dugesi (Epicauta tamara Adams & Selander, 1979); we designate lectotype for Lytta koltzei var. minor Haag-Rutenberg, 1880 with the goal of resolving the taxonomic problem generated by the previous invalid designation of lectotype for L. k. var. cyanescens; and finally we consider Cissites maculata (Swederus, 1787) and Tetraonyx (Tetraonyx) bimaculatus (Klug, 1825) as species to be possibly excluded from the Mexican checklist., Este trabajo ha contado para su realización con los proyectos CGL2004-04680-C10-10/BOS y CGL2007-64621 del Ministerio de Educación y Ciencia, lo que nos ha facilitado el apoyo logístico necesario. La visita a la colección del Magyar Természettudomány Múzeum (HNHM) en Budapest ha sido financiada por el proyecto Synthesys «European Commission´s Research Infrastructure Action».

Batrachochytrium salamandrivorans (Bsal) is an emerging fungal pathogen that has caused recent die-offs of native salamanders in Europe and is known to be lethal to at least some North American species in laboratory trials [1]. Bsal appears to have originated in Asia, and may have been introduced by humans into wild populations in Europe through commercial trade of amphibians [1]. Since the first outbreaks of Bsal in the Netherlands, it has been the etiologic agent of mortality events in Belgium (wild) and Germany (captivity), and was recently found in imported salamanders in the United Kingdom [1–4]. Substantial concern has been raised about the associated risk of Bsal to native salamanders in North America [5]. Herein, we review what policy actions are occurring in North America and elsewhere, and call for creation of a North American Bsal Strategic Plan.

9 páginas, 2 figuras et al.., [EN] We describe two new species of salamanders of the genus Pseudoeurycea from mountains in the northern part of the state of Oaxaca, Mexico. Pseudoeurycea papenfussi, a large, muscular member of the P. gadovii group, occurs near the peaks (just below 3000 m) of the highest mountains of the Sierra de Jua´rez. It is related to P. smithi, a more southerly species, and possibly to P. aquatica, another species from Oaxaca. Pseudoeurycea obesa, a rotund member of the P. leprosa group, is known only from the type locality in the Sierra Mazateca at the northernmost extremity of Oaxaca. It is related to P. werleri and P. mystax, which are known from more southern parts of Oaxaca. These descriptions bring to 27 the number of species of salamanders known from Oaxaca. Most of these species are endemic to the state and are known only from regions that are undergoing rapid habitat modification and destruction., [ES] Describimos dos especies nuevas de salamandras del genero Pseudoeurycea de las montañas del norte del Estado de Oaxaca, Mexico. Pseudoeurycea papenfussi es una especie de gran tamaño, de aspecto musculoso, incluida en el grupo de P. gadovii, que se encuentra cerca de las cumbres (justo por debajo de los 3000 m) de las montañas mas altas de la Sierra de Juarez. Esta relacionada con P. smithi, que se encuentra en regiones mas meridionales, y posiblemente con P. aquatica, tambien de Oaxaca. Pseudoeurycea obesa, es una especie rechoncha del grupo de P. leprosa, que unicamente se conoce la localidad tıpica en la Sierra Mazateca del extremo noroccidental de Oaxaca., This work has been partially funded by the David Rockefeller Center for Latin American Studies, Harvard University (to JH), UC-MEXUS CN-02–74 (GP-O and DBW), SEMAMATCONACYT 2002-C01–0015 (GP-O), CSIC-CONACYT 2004MX0011 (GP-O and MG-P), and by NSF EF-0334846 ( JH) and EF-0334939 (DBW). SEMARNAT provided collecting permits (FAUT.0106, to GP-O). Animal use was approved by the University of California, Berkeley, protocol R093–0205 (to DBW).

A generalized decline of amphibian populations is occurring worldwide. The causes for such a decline are not completely understood; however, climate change has been identified as a possible cause for amphibian extinction, among others. Ecological niche modeling has proven to be a useful tool to predict potential distribution of species in the context of climatic changes. In this paper, we used the Genetic Algorithm for Rule-set Prediction (GARP) to model the potential distributions of two species of plethodontid salamanders: Pseudoeurycea cephalica and P. leprosa. We projected their potential distributions under climatic scenarios expected in 50 yr based on a conservative scenario of global climate change and assuming a moderate dispersal ability for both species. Our analyses suggest that climate change effects may pose an additional long-term risk to both species of plethodontid salamanders, with a more dramatic scenario in the case of P. leprosa. By the year 2050, this species may lose almost 75 percent of its distributional area, and this projection is even worse when deforestation (in the way it is occurring at present) is considered within the predicted model. Our results concur with those obtained for species with limited dispersal capability because they do not track changing climates, but rather face a loss of distributional area. The survival of these species is not secure, even though their potential distributional area falls within a considerable number of natural protected areas. RESUMEN El declive de las poblaciones de anfibios a nivel mundial es un hecho bien documentado. Diversos factores se han identificado como las causas del declive, y entre ellos, el cambio climatico se ha senalado como un factor importante en la extincion de poblaciones de anfibios. El modelado de nicho ecologico ha demostrado ser una herramienta util para predecir la distribucion potencial de las especies en el contexto del cambio climatico global. En el presente trabajo utilizamos el algoritmo GARP (Genetic Algorithm for Rule-set Prediction) para modelar la distribucion de dos especies de salamandras pletodontidas: Pseudoerycea cephalica and P. leprosa; asimismo, proyectamos su distribucion potencial bajo escenarios de cambio climatico esperados que ocurran en 50 anos, basandonos en un escenario de cambio global conservativo y asumiendo una capacidad de dispersion moderada para ambas especies de salamandras. Nuestros analisis sugieren que el cambio climatico puede representar un riesgo adicional para ambas especies, siendo el escenario aun mas dramatico para el caso de P. leprosa. Para el ano 2050, podriamos esperar que esta especie perdiera alrededor del 75 por ciento de su area de distribucion y si consideramos la deforestacion (tal como ocurre en el presente), la proyeccion seria aun mas desoladora. Nuestros resultados concuerdan con aquellos obtenidos en especies con una capacidad de dispersion limitada dado que estas no responden a los cambios climaticos desplazandose a zonas mas favorables, sino que enfrentan una perdida de su area de distribucion. La supervivencia de estas especies de salamandra esta en riesgo, sin embargo el area de distribucion potencial esta comprendida dentro de un numero considerable de Areas Naturales Protegidas.

The loss of global amphibian biodiversity has been well documented in recent years. The greatest information from Latin America came from countries such as Costa Rica, Panama, Ecuador, and Puerto Rico. The five papers in this special section illustrate the critical status of Latin American amphibians and further demonstrate certain commonalities of amphibian population declines within the region. These studies provide a framework by which future research and management could proceed in all tropical regions. RESUMEN En los pasados anos se ha documentado la perdida de biodiversidad de anfibios en muchas partes del mundo. La mayor informacion con respecto a America Latina proviene de trabajos realizados en Costa Rica, Panama, Ecuador y Puerto Rico. Los cinco trabajos de esta edicion especial ilustran el estado critico de los anfibios en America Latina y demuestran que existen algunos elementos comunes en los patrones de disminuciones poblacionales de anfibios en la region. Estos estudios proveen un marco de referencia para futuras investigaciones y desarrollo de planes de manejo en regiones tropicales.