Atelopus

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Roberto Ibáñez - One of the best experts on this subject based on the ideXlab platform.

  • Whole exome sequencing identifies the potential for genetic rescue in iconic and critically endangered Panamanian harlequin frogs.
    Global change biology, 2020
    Co-Authors: Allison Q. Byrne, Corinne L. Richards-zawacki, Roberto Ibáñez, Jamie Voyles, Erica Bree Rosenblum
    Abstract:

    Avoiding extinction in a rapidly changing environment often relies on a species' ability to quickly adapt in the face of extreme selective pressures. In Panama, two closely related harlequin frog species (Atelopus varius and Atelopus zeteki) are threatened with extinction due to the fungal pathogen Batrachochytrium dendrobatidis (Bd). Once thought to be nearly extirpated from Panama, A. varius have recently been rediscovered in multiple localities across their historical range; however, A. zeteki are possibly extinct in the wild. By leveraging a unique collection of 186 Atelopus tissue samples collected before and after the Bd outbreak in Panama, we describe the genetics of persistence for these species on the brink of extinction. We sequenced the transcriptome and developed an exome-capture assay to sequence the coding regions of the Atelopus genome. Using these genetic data, we evaluate the population genetic structure of historical A. varius and A. zeteki populations, describe changes in genetic diversity over time, assess the relationship between contemporary and historical individuals, and test the hypothesis that some A. varius populations have rapidly evolved to resist or tolerate Bd infection. We found a significant decrease in genetic diversity in contemporary (compared to historical) A. varius populations. We did not find strong evidence of directional allele frequency change or selection for Bd resistance genes, but we uncovered a set of candidate genes that warrant further study. Additionally, we found preliminary evidence of recent migration and gene flow in one of the largest persisting A. varius populations in Panama, suggesting the potential for genetic rescue in this system. Finally, we propose that previous conservation units should be modified, as clear genetic breaks do not exist beyond the local population level. Our data lay the groundwork for genetically informed conservation and advance our understanding of how imperiled species might be rescued from extinction.

  • Recent and Rapid Radiation of the Highly Endangered Harlequin Frogs (Atelopus) into Central America Inferred from Mitochondrial DNA Sequences
    Diversity, 2020
    Co-Authors: Juan P. Ramirez, Erik D. Lindquist, César Jaramillo, Andrew J. Crawford, Roberto Ibáñez
    Abstract:

    Populations of amphibians are experiencing severe declines worldwide. One group with the most catastrophic declines is the Neotropical genus Atelopus (Anura: Bufonidae). Many species of Atelopus have not been seen for decades and all eight Central American species are considered “Critically Endangered”, three of them very likely extinct. Nonetheless, the taxonomy, phylogeny, and biogeographic history of Central American Atelopus are still poorly known. In this study, the phylogenetic relationships among seven of the eight described species in Central America were inferred based on mitochondrial DNA sequences from 103 individuals, including decades-old museum samples and two likely extinct species, plus ten South American species. Among Central American samples, we discovered two candidate species that should be incorporated into conservation programs. Phylogenetic inference revealed a ladderized topology, placing species geographically furthest from South America more nested in the tree. Model-based ancestral area estimation supported either one or two colonization events from South America. Relaxed-clock analysis of divergence times indicated that Atelopus colonized Central America prior to 4 million years ago (Ma), supporting a slightly older than traditional date for the closure of the Isthmus. This study highlights the invaluable role of museum collections in documenting past biodiversity, and these results could guide future conservation efforts. An abstract in Spanish (Resumen) is available as supplementary material.

  • Conserving Panamanian harlequin frogs by integrating captive-breeding and research programs
    Biological Conservation, 2019
    Co-Authors: Carrie H.r. Lewis, Corinne L. Richards-zawacki, Roberto Ibáñez, Jennifer Luedtke, Jamie Voyles, Paul R. Houser, Brian Gratwicke
    Abstract:

    Abstract Captive breeding programs are a valuable conservation strategy, particularly when integrated with research goals. Panamanian Harlequin frogs (genus Atelopus) serve as a case study for integrating captive breeding and research goals because they have experienced drastic chytridiomycosis-related declines and have large captive populations. Captive breeding efforts in Panama and the United States established secure ex-situ populations of Atelopus certus, A. glyphus, A. limosus, A. varius, and A. zeteki. Atelopus chiriquiensis is presumed to be extinct with no captive populations. The status of one undescribed species, Atelopus aff. limosus, has not been evaluated and no secure captive population has yet been established. Captive breeding efforts that produce a surplus of Atelopus are an important resource for research into collections management, disease mitigation, and adaptive management approaches for Atelopus reintroduction efforts. We reevaluated all Panamanian Atelopus species through the IUCN Redlist and compiled occurrence records for Panamanian Atelopus species to create a historical distribution map. We model Atelopus habitat suitability using Maxent and found annual mean air temperature to be the best predictor of Atelopus occurrence. The model will improve our knowledge of their likely spatial distribution and guide future conservation and reintroduction efforts. The recent proliferation of molecular tools, climate models, bio-banking, and reproductive technologies position us to address multiple applied and basic evolutionary questions such as: What factors cause differential disease outcomes? Do persisting populations have heritable traits associated with improved survivorship? Are there climatic refugia from disease? Ultimately, the answers to these questions will help us develop applied solutions and facilitate the reestablishment of self-sustaining wild populations.

  • The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.).
    PloS one, 2018
    Co-Authors: Julio Federico Camperio Ciani, Roberto Ibáñez, Jorge Guerrel, Eric Baitchman, Rigoberto Diaz, Matthew Evans, Heidi Ross, Eric Klaphake, Bradley D. Nissen, Allan P. Pessier
    Abstract:

    Spindly Leg Syndrome (SLS) is a persistent animal welfare issue associated with the rearing of amphibians in captivity. We conducted two experiments to investigate the effects of diet, water composition and overfeeding on prevalence of SLS in newly metamorphosed harlequin frogs (Atelopus spp.). In our first experiment, we offered 400 full-sibling tadpoles of Atelopus certus isocaloric diets in treatments of 31%, 37%, 42% and 48% crude protein respectively. Tadpoles fed higher protein diets metamorphosed faster, but the incidence of SLS exceeded 80% in all treatments leading to the conclusion that variation in dietary protein was not responsible for causing SLS. We used 720 full-sibling Atelopus glyphus tadpoles in a second experiment to examine the effects of diet type, water composition and diet ration on SLS. We found that an overall incidence of 58% spindly leg in tadpoles reared in tap water, but reduced to about 10% in water treated by reverse osmosis and then reconstituted. It is possible that the reverse osmosis treatment removed some factor that caused the SLS, or that the reconstitution may have added a mineral lacking in the original tap water. Within tap water treatments, overfeeding tadpoles in tanks increased the incidence of SLS. We recommend further experimental research into this condition to identify the causative factors in the water. Additional research into the nutritional composition of food available to wild tadpoles would be useful in formulating captive diets, that have to date been solely based on surrogate species.

  • External Reinfection of a Fungal Pathogen Does not Contribute to Pathogen Growth.
    EcoHealth, 2018
    Co-Authors: Graziella V. Direnzo, Roberto Ibáñez, Kelly R. Zamudio, Tate S. Tunstall, Maya S. Devries, Ana V. Longo, Karen R. Lips
    Abstract:

    Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which has led to devastating declines in amphibian populations worldwide. Current theory predicts that Bd infections are maintained through both reproduction on the host’s skin and reinfection from sources outside of the host. To investigate the importance of external reinfection on pathogen burden, we infected captive-bred individuals of the highly susceptible Panamanian Golden Frog, Atelopus glyphus, and wild-caught glass frogs, Espadarana prosoblepon, with Bd. We housed the animals in one of three treatments: individually, in heterospecific pairs, and in conspecific pairs. For 8 weeks, we measured the Bd load and shedding rate of all frogs. We found that Atelopus had high rates of increase in both Bd load and shedding rate, but pathogen growth rates did not differ among treatments. The infection intensity of Espadarana co-housed with Atelopus was indistinguishable from those housed singly and those in conspecific pairs, despite being exposed to a large external source of Bd zoospores. Our results indicate that Bd load in both species is driven by pathogen replication within an individual, with reinfection from outside the host contributing little to the amplification of host fungal load.

Stefan Lötters - One of the best experts on this subject based on the ideXlab platform.

  • The voice from the hereafter: vocalisations in three species of Atelopus from the Venezuelan Andes, likely to be extinct
    Herpetozoa, 2019
    Co-Authors: Stefan Lötters, Dietrich Mebs, Gunther Köhler, Joseph Vargas, Enrique La Marca
    Abstract:

    Atelopus is a species-rich group of Neotropical bufonids. Present knowledge on bioacoustics in this genus is relatively poor, as vocalisations have been described in only about one fifth of the ca. 100 species known. All studied members of the genus produce vocalisations although, with a few exceptions, most species lack a middle ear. Nonetheless, hearing has been demonstrated even in earless Atelopus making bioacoustics in these toads an inspiring research field. So far, three structural call types have been identified in the genus. As sympatry is uncommon in Atelopus, calls of the same type often vary little between species. Based on recordings from the 1980s, we describe vocalisations of three Venezuelan species (A. carbonerensis, A. mucubajiensis, A. tamaense) from the Cordillera de Mérida, commonly known as the Andes of Venezuela and the Tamá Massif, a Venezuelan spur of the Colombian Cordillera Oriental. Vocalisations correspond, in part, to the previously identified call types in Atelopus. Evaluation of the vocalisations of the three species presented in this study leads us to recognise a fourth structural call type for the genus. With this new addition, the Atelopus acoustic repertoire now includes (1) pulsed calls, (2) pure tone calls, (3) pulsed short calls and (4) pure tone short calls. The call descriptions provided here are valuable contributions to the bioacoustics of these Venezuelan Atelopus species, since all of them have experienced dramatic population declines that limit possibilities of further studies.

  • Notes on vocalizations in three species of Atelopus from Central and South America
    2015
    Co-Authors: Stefan Lötters, Frank Glaw, Eberhard Meyer
    Abstract:

    bei anderen Arten. We report on short calls in three species of Atelopus. In two (A. peruensis GRAY & CANNATELLA, 1985, A. tricolor BOULENGER, 1902) vocalizations were previously unknown; in the third (A. chiriquiensis SHREVE, 1936) they resemble short call descriptions from elsewhere within its distribution range. Short calls in these taxa are compa-rable to those known from other species of the genus. Concerning/I. tricolor, we also report on a distinctly longer call. In overall structure it corresponds to the pulsed call type known in Atelopus species, although it is considerably shorter than in other species

  • Notes on vocalizations in three species of Atelopus
    2014
    Co-Authors: Stefan Lötters, Frank Glaw, Steffen Reichle, Jörn Köhler, Eberhard Meyer
    Abstract:

    bei anderen Arten. We report on short calls in three species of Atelopus. In two (A. peruensis GRAY & CANNATELLA, 1985, A. tricolor BOULENGER, 1902) vocalizations were previously unknown; in the third (A. chiriquiensis SHREVE, 1936) they resemble short call descriptions from elsewhere within its distribution range. Short calls in these taxa are compa-rable to those known from other species of the genus. Concerning/1. tricolor, we also report on a distinctly longer call. In overall structure it corresponds to the pulsed call type known in Atelopus species, although it is considerably shorter than in other species. KEY WORDS Amphibia, Anura, Bufonidae, Atelopus chiriquiensis, A- peruensis, A. tricolor, vocalizations, Neotropics Contrary to anurans in general, in COCROFT & al. (1990) noted three different Neotropical bufonids of the genus Atelopus call types among eight Atelopus species acoustic communication has been sug- analyzed: pulsed calls having a duration of gested to be of minor importance; indi- 227-1240 ms, pure tone calls lasting 180-viduals communicate primarily by visual 297 ms, and short calls with a duration o

  • Assessing the molecular phylogeny of a near extinct group of vertebrates: the Neotropical harlequin frogs (Bufonidae; Atelopus)
    Systematics and Biodiversity, 2011
    Co-Authors: Stefan Lötters, Edgar Lehr, Luis A. Coloma, Renaud Boistel, Peter Cloetens, Raffael Ernst, Arie Van Der Meijden, Michael Veith
    Abstract:

    Neotropical harlequin frogs, Atelopus, are a species-rich bufonid group. Atelopus monophyly has been suggested but intergeneric, interspecific and intraspecific relationships are poorly understood. One reason is that morphological characters of harlequin frogs are often difficult to interpret, making species delimitations difficult. Molecular analyses (DNA barcoding, phylogeny) may be helpful but sampling is hampered as most of the more than 100 Atelopus species have undergone severe population declines and many are possibly extinct. We processed mitochondrial DNA (12S and 16S rRNA) of 28 available ingroup samples from a large portion of the genus’ geographic range (Bayesian Inference, Maximum Likelihood). Our samples constitute a monophyletic unit, which is sister to other bufonid genera studied including the Andean genus Osornophryne. In contrast to previous morphological studies, our results suggest that Osornophryne is neither sister to Atelopus nor nested within it. Within Atelopus, we note two major...

  • Reinforcing and expanding the predictions of the disturbance vicariance hypothesis in Amazonian harlequin frogs: a molecular phylogenetic and climate envelope modelling approach
    Biodiversity and Conservation, 2010
    Co-Authors: Stefan Lötters, Enrique La Marca, Arie Meijden, Dennis Rödder, Timo E. Köster, Tanja Kraus, Célio F. B. Haddad, Michael Veith
    Abstract:

    The disturbance vicariance hypothesis (DV) has been proposed to explain speciation in Amazonia, especially its edge regions, e.g. in eastern Guiana Shield harlequin frogs ( Atelopus ) which are suggested to have derived from a cool-adapted Andean ancestor. In concordance with DV predictions we studied that (i) these amphibians display a natural distribution gap in central Amazonia; (ii) east of this gap they constitute a monophyletic lineage which is nested within a pre-Andean/western clade; (iii) climate envelopes of Atelopus west and east of the distribution gap show some macroclimatic divergence due to a regional climate envelope shift; (iv) geographic distributions of climate envelopes of western and eastern Atelopus range into central Amazonia but with limited spatial overlap. We tested if presence and apparent absence data points of Atelopus were homogenously distributed with Ripley’s K function. A molecular phylogeny (mitochondrial 16S rRNA gene) was reconstructed using Maximum Likelihood and Bayesian Inference to study if Guianan Atelopus constitute a clade nested within a larger genus phylogeny. We focused on climate envelope divergence and geographic distribution by computing climatic envelope models with MaxEnt based on macroscale bioclimatic parameters and testing them by using Schoener’s index and modified Hellinger distance. We corroborated existing DV predictions and, for the first time, formulated new DV predictions aiming on species’ climate envelope change. Our results suggest that cool-adapted Andean Atelopus ancestors had dispersed into the Amazon basin and further onto the eastern Guiana Shield where, under warm conditions, they were forced to change climate envelopes.

Allan P. Pessier - One of the best experts on this subject based on the ideXlab platform.

Jorge Guerrel - One of the best experts on this subject based on the ideXlab platform.

Julio Federico Camperio Ciani - One of the best experts on this subject based on the ideXlab platform.