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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, 2020Co-Authors: Allison Q. Byrne, Corinne L. Richards-zawacki, Roberto Ibáñez, Jamie Voyles, Erica Bree RosenblumAbstract:
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 SequencesDiversity, 2020Co-Authors: Juan P. Ramirez, Erik D. Lindquist, César Jaramillo, Andrew J. Crawford, Roberto IbáñezAbstract:
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 programsBiological Conservation, 2019Co-Authors: Carrie H.r. Lewis, Corinne L. Richards-zawacki, Roberto Ibáñez, Jennifer Luedtke, Jamie Voyles, Paul R. Houser, Brian GratwickeAbstract:
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.
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 extinctHerpetozoa, 2019Co-Authors: Stefan Lötters, Dietrich Mebs, Gunther Köhler, Joseph Vargas, Enrique La MarcaAbstract:
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, 2015Co-Authors: Stefan Lötters, Frank Glaw, Eberhard MeyerAbstract:
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, 2014Co-Authors: Stefan Lötters, Frank Glaw, Steffen Reichle, Jörn Köhler, Eberhard MeyerAbstract:
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
Allan P. Pessier – One of the best experts on this subject based on the ideXlab platform.
The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.).PloS one, 2018Co-Authors: Julio Federico Camperio Ciani, Roberto Ibáñez, Jorge Guerrel, Eric Baitchman, Rigoberto Diaz, Matthew Evans, Heidi Ross, Eric Klaphake, Bradley D. Nissen, Allan P. PessierAbstract:
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.
Summary of Atelopus glyphus post-metamorph survivorship at 376 days., 2018Co-Authors: Julio Federico Camperio Ciani, Roberto Ibáñez, Jorge Guerrel, Eric Baitchman, Rigoberto Diaz, Matthew Evans, Heidi Ross, Eric Klaphake, Bradley Nissen, Allan P. PessierAbstract:
Summary of Atelopus glyphus post-metamorph survivorship at 376 days.
The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.) – Fig 1, 2018Co-Authors: Julio Federico Camperio Ciani, Roberto Ibáñez, Jorge Guerrel, Eric Baitchman, Rigoberto Diaz, Matthew Evans, Heidi Ross, Eric Klaphake, Bradley Nissen, Allan P. PessierAbstract:
Atelopus certus post-metamorphs, an example of a SLS frog with poorly developed forelimbs (left) compared with a healthy froglet from the same clutch (right).