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Explaining Andean megadiversity: The evolutionary and ecological causes of glassfrog elevational richness patterns
(2013)
Hutter C.R.
;
Guayasamin J.M.
;
Wiens J.J.
The Tropical Andes are an important global biodiversity hotspot, harbouring extraordinarily high richness and endemism. Although elevational richness and speciation have been studied independently in some Andean groups, the evolutionary and ecological processes that explain elevational richness patterns in the Andes have not been analysed together. Herein, we elucidate the processes underlying Andean richness patterns using glassfrogs (Centrolenidae) as a model system. Glassfrogs show the widespread mid-elevation diversity peak for both local and regional richness. Remarkably, these patterns are explained by greater time (montane museum) rather than faster speciation at mid-elevations (montane species pump), despite the recency of the major Andean uplift. We also show for the first time that rates of climatic-niche evolution and elevational change are related, supporting the hypothesis that climatic-niche conservatism decelerates species' shifts in elevational distributions and underlies the mid-elevation richness peak. These results may be relevant to other Andean clades and montane systems globally. © 2013 John Wiley & Sons Ltd/CNRS.
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To name or not to name: Criteria to promote economy of change in Linnaean classification schemes
(2013)
Vences M.
;
Guayasamin J.M.
;
Miralles A.
;
De La Riva I.
The Linnaean classification system provides the universal reference system for communicating about the diversity of life and its hierarchic history. Several limitations that challenge the stability of this system have been identified and, as a result, alternative systems have been proposed since its early inception. The revolution caused by molecular phylogenetics has, more than ever, exemplified that Linnaean classification schemes are subject to a degree of instability that may hamper their significance and communication power. Our analysis of recent changes in the classification of several groups of organisms, with a focus on amphibians and reptiles, reveals two main sources of instability: (i) revisionary, objective (empirical) changes based on the discovery of unambiguous instances of non-monophyly and on progress in the Globe's species inventory, and (ii) subjective changes based on author preferences or on a poor analysis of the advantages and limitations of new classification schemes. To avoid subjective taxonomic instability, we review and elaborate proposals for the assignment of Linnaean rank to clades, and thereby for the naming of these clades as Linnaean taxa (Taxon Naming Criteria: TNCs). These are drafted from the perspective of practicing taxonomists and can help choosing among alternative monophyly-based classifications under a premise of economy of change. We provide a rationale for each TNC along with real and theoretical examples to illustrate their practical advantages and disadvantages. We conclude that not all TNCs lead to equally informative and stable taxonomies. Therefore, we order the various TNCs by the generality of their implications and provide a workflow scheme to guide the procedure of taxonomic decisions concerning the creation or modification of supraspecific classifications. The following criteria are considered primary when naming taxa: (i) Mono-phyly of the taxon in an inferred species tree; (ii) Clade Stability, i.e., the monophyly of a clade to be named as taxon should be as strongly supported as possible by various methods of tree inference, tests of clade robustness, and different data sets; and (iii) Phenotypic Diagnosability, i.e., ranked supraspecific taxa should be those that are phenotypically most conspicuous although in phenotypically cryptic groups of organisms it can be warranted to name taxa based on molecular differences alone. We consider various other criteria as secondary (i.e., the Time Banding, Biogeography, Adaptive Zone, and Hybrid Viability TNCs) and refute using them as sole arguments for the modification of established classifications or proposal of new ones. Taxonomists are encouraged to be explicit and consistent when applying TNCs for creating or modifying classifications. We emphasize that, except for monophyly, the priority TNCs are not proposed as mandatory requisites of a Linnaean taxon but as yardsticks to allow for an informed choice among various clades in a tree that could alternatively be named as Linnaean taxa. Despite a need for plurality, classifications should avoid deliberately violating any of the three primary TNCs because taxa of unstable monophyly or poor diagnosability reduce the information content and hence the utility of the Linnaean system. Copyright © 2013 Magnolia Press.
Scopus© Citations 155 6
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On the Origin of Pantepui montane biotas: A Perspective Based on the Phylogeny of Aulacorhynchus toucanets
(2013)
Bonaccorso, Elisa
;
Guayasamin J.M.
To understand the origin of Pantepui montane biotas, we studied the biogeography of toucanets in the genus Aulacorhynchus. These birds are ideal for analyzing historical relationships among Neotropical montane regions, given their geographic distribution from Mexico south to Bolivia, including northern Venezuela (Cordillera de la Costa), and the Pantepui. Analyses were based on molecular phylogenies using mitochondrial and nuclear DNA sequences. Topology tests were applied to compare alternative hypotheses that may explain the current distribution of Aulacorhynchus toucanets, in the context of previous hypotheses of the origin of Pantepui montane biotas. Biogeographic reconstructions in RASP and Lagrange were used to estimate the ancestral area of the genus, and an analysis in BEAST was used to estimate a time framework for its diversification. A sister relationship between the Pantepui and Andes+Cordillera de la Costa was significantly more likely than topologies indicating other hypothesis for the origin of Pantepui populations. The Andes was inferred as the ancestral area for Aulacorhynchus, and the group has diversified since the late Miocene. The biogeographic patterns found herein, in which the Andes are the source for biotas of other regions, are consistent with those found for flowerpiercers and tanagers, and do not support the hypothesis of the geologically old Pantepui as a source of Neotropical montain diversity. Based on the high potential for cryptic speciation and isolation of Pantepui populations, we consider that phylogenetic studies of additional taxa are important from a conservation perspective. © 2013 Bonaccorso, Guayasamin.
Scopus© Citations 25 23
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A new yellow species of glassfrog (Centrolenidae: Nymphargus) from the Amazonian slopes of the Ecuadorian Andes
(2013)
Guayasamin J.M.
I describe a new glassfrog from the cloud forest of the Andes of southwestern Ecuador (Plan de Milagro-Gualaceo road; 3.0077°S, 78.53318°W), at elevations between 2140-2160 m. The new species is distinguished mostly by having a pale yellow dorsal coloration instead of the green that characterizes most centrolenids. Morphological traits (i.e., reduced web-bing between Fingers III and IV and lack of humeral spines) support the placement of the new species in the genus Nymph-argus. Copyright © 2013 Magnolia Press.
Scopus© Citations 6 6
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Notes on the taxonomy of some glassfrogs from the andes of Peru and Ecuador (Amphibia: Centrolenidae)
(2014)
Cisneros-Heredia D.F.
;
Guayasamin J.M.
We present new information on several species of centrolenid frogs from Ecuador and Peru that justify the placement of Centrolene fernandoi Duellman and Schulte as a junior synonym of Centrolenella audax Lynch and Duellman; Centrolenella puyoensis Flores & McDiarmid as a synonym of Centrolenella mariae Duellman & Toft; and Cochranella tangarana Du-ellman & Schulte as a synonym of Cochranella saxiscandens Duellman & Schulte.
Scopus© Citations 4 5
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High levels of diversity uncovered in a widespread nominal taxon: Continental phylogeography of the neotropical tree frog dendropsophus minutus
(2014)
Gehara M.
;
Crawford A.J.
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Orrico V.G.D.
;
Rodríguez A.
;
Lötters S.
Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI) and the 16S rhibosomal gene (16S) for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered. © 2014 Gehara et al.
Scopus© Citations 126 8
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Systematics of nothopsini (Serpentes, Dipsadidae), with a new species of synophis from the pacific andean slopes of southwestern Ecuador
(2015)
Pyron R.A.
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Guayasamin J.M.
;
Peñafiel N.
;
Bustamante L.
;
Arteaga A.
Within Dipsadinae, some recent authors have recognized a tribe Nothopsini containing the genera Diaphorolepis, Emmochliophis, Nothopsis, Synophis, and Xenopholis, on the basis of a number of putative morphological synapomorphies. However, molecular results suggest that Nothopsis, Synophis, and Xenopholis do not form a monophyletic group, while the remaining taxa are unsampled in recent molecular phylogenies. Here, DNA-sequence data for some Diaphorolepis and Synophis species are provided for the first time, as well as additional new sequences for Nothopsis and some Synophis species. Including these and other existing data for nothopsine species, previous studies showing that Nothopsini is not a natural group are corroborated. Nothopsini Cope, 1871 is restricted to Nothopsis. Diaphorolepidini Jenner, 1981 is resurrected and re-delimited to include only Diaphorolepis, Emmochliophis, and Synophis. Finally, Xenopholis remains Dipsadinae incertae sedis. Known material of Diaphorolepidini is reviewed to generate revised and expanded descriptions and diagnoses at the tribe, genus, and species level. Numerous cryptic species are likely present in S. bicolor and S. lasallei. Finally, a new population from the low-elevation cloud forests of SW Ecuador is reported upon, which is genetically and morphologically distinct from all other species, that is here named Synophis zaheri sp. n. © R. Alexander Pyron et al.
Scopus© Citations 22 8
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Molecular phylogeny of stream treefrogs (Hylidae: Hyloscirtus bogotensis Group), with a new species from the Andes of Ecuador
(2015)
Guayasamin J.M.
;
Rivera-Correa M.
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Arteaga A.
;
Culebras J.
;
Bustamante L.
We present a new molecular phylogeny of the stream treefrog genus Hyloscirtus, with an improved taxon sampling in the Hyloscirtus bogotensis group. The tree supports the existence of three clades within the genus (Hyloscirtus armatus group, H. bogotensis group and Hyloscirtus larinopygion group) in congruence with previous studies, and suggests the presence of at least three new species in the H. bogotensis group. Herein, we describe one of these species, Hyloscirtus mashpi n. sp. from the Pacific slope of the Ecuadorian Andes. The validity of the latter is supported by molecular, morphological and acoustic data. We also tested individuals of the new species for the chytrid fungus Batrachochytrium dendrobatidis, finding a prevalence of 17.6% (6 positives and 28 negatives). However, at sampled streams, frog densities were high, suggesting that H. mashpi n. sp. may be tolerant to the infection. © 2015, © 2015 The Author(s). Published by Taylor & Francis.
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Rainbow trout (Oncorhynchus mykiss) threaten Andean amphibians
(2016)
Martín-Torrijos L.
;
Sandoval-Sierra J.V.
;
Muñoz J.
;
Diéguez-Uribeondo J.
;
Bosch J.
Amphibian populations are declining due to a myriad of abiotic and biotic factors, including invasive species and pathogens. In temperate freshwater ecosystems, for example, amphibian populations are threatened by the predation of introduced salmonids. Salmonids not only directly predate upon amphibian eggs and larvae but may also transport deadly pathogens into freshwater systems. Though most research has focused on temperate systems, much less is known about the effects of introduced species in Neotropical streams. We conducted two experiments to investigate the impacts of rainbow trout (Oncorhynchus mykiss) in two Neotropical anurans. First, we assessed the effect of the rainbow trout on tadpole survivorship and morphology in Nymphargus grandisonae, a glassfrog species endemic of the Andes. Tadpoles of N. grandisonae were subjected to three treatments involving the absence of rainbow trout (control) and its presence with different types of chemical cues–kairomones (from rainbow trout) and cue alarms (from tadpole prey); the results show that the presence of rainbow trout affects the larval morphology of this glassfrog. In the second experiment, to test whether rainbow trout is a vector of the pathogenic freshwater mold Saprolegnia diclina (Oomycetes), eggs of Engystomops petersi were placed with infected and uninfected rainbow trout. There was a high mortality rate in the embryos of E. petersi exposed to trout infected with S. diclina. This represents the first evidence that rainbow trout may have a direct negative effect on Neotropical amphibian populations, and thus should be considered a threat. Management programs should be implemented to eradicate trout from Andean rivers, especially in areas with high number of endangered amphibians. © 2016, © 2016 The Author(s). Published by Taylor & Francis.
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Cryptic diversity concealed in the Andean cloud forests: two new species of rainfrogs (Pristimantis) uncovered by molecular and bioacoustic data
(2015)
Hutter C.R.
;
Guayasamin J.M.
Two new species of frogs previously confused with Pristimantis calcarulatus are identified using molecular phylogenetics and described using an integrative taxonomic approach. The species are distributed in montane cloud forests of the northwestern Ecuadorian Andes. Pristimantis pahuma n. sp. and Pristimantis cedros n. sp. differ from their closest relatives by strongly supported reciprocal monophyly in mitochondrial genetic data (16S). Additionally, the genetic distance among P. cedros n. sp., P. pahuma n. sp. and P. calcarulatus (sensu stricto) is 7.1–9.5%. The advertisement call of P. pahuma n. sp. also differs from that of P. calcarulatus; the former emits single-note calls irregularly, whereas P. calcarulatus always calls in a series of 8–24 notes (calls for P. cedros n. sp. not recorded). Morphologically, the three species are almost undistinguishable; however, P. cedros n. sp. differs in life by having an iris with more numerous and smaller black reticulations, whereas the other two species have larger and fewer reticulations. Biogeographically, P. cedros n. sp. is separated from P. pahuma n. sp. and P. calcarulatus by the climatically dry and low elevation Río Guayllabamba Valley, which acts as a strong barrier to dispersal in these frogs. The results of this and other studies suggest that the true species richness of Pristimantis in the Andes is vastly underestimated. This underestimation may lead to declining protection for such cryptic species, many of which have smaller ranges than previously assumed. Species distributed across potential geographic barriers should be studied to detect the existence of cryptic species. © 2015, © 2015 The Author(s). Published by Taylor & Francis.
Scopus© Citations 34 13

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