Evan Twomey

Dr. Evan Twomey


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 August 2014 in Zootaxa
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Journal Article
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ETEvan Twomey
Evan Twomey
JDJesse Delia
Jesse Delia
SCSantiago Castroviejo-Fisher
Santiago Castroviejo-Fisher
Peru is well known for amphibian diversity and endemism, yet there have been relatively few field studies of glassfrog (Centrolenidae) diversity in this country. Research in Colombia and Ecuador indicates that centrolenid diversity is higher in the northern Andes. However, part of this trend appears to be due to sampling effort. We conducted fieldwork throughout northern Peru, and based on phylogenetic analysis of DNA sequences, combined with bioacoustic and morphological analyses of new and available material we now recognize 33 species from the country (versus 30 species prior to this work). Field surveys led to the discovery of four remarkable species: Centrolene charapita new species is a large, ornamented glassfrog that appears to be sister to Ce. geckoideum; Chimerella corleone new species represents the second-known member of the genus Chimerella; Cochranella guayasamini new species is the second-known member of the genus with humeral spines; and Hyalinobatrachium anachoretus new species occurs in the cloud forest of the east-Andean versant in Peru. In addition to the new species described here, we provide new country records, new localities including range extensions of up to 875 km, information on diagnostic characters and phylogenetic relationships, call and larval descriptions, and observations on natural history for several Peruvian centrolenids. Our results also revealed several taxonomic problems concerning species of the genus Rulyrana, and we conclude that R. croceopodes and R. tangarana are junior synonyms of R. saxiscandens. By implication of our phylogenetic analyses, we recognize the following new combinations: Espadarana audax new combination, Espadarana durrelorum new combination, and Espadarana fernandoi new combination.

1 February 2016 in The American Naturalist
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Journal Article
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ETEvan Twomey
Evan Twomey
JVJacob S. Vestergaard
Jacob S. Vestergaard
PVPablo Javier Venegas
Pablo Javier Venegas
KSKyle Summers
Kyle Summers
While divergent ecological adaptation can drive speciation, understanding the factors that facilitate or constrain this process remains a major goal in speciation research. Here, we study two mimetic transition zones in the poison frog Ranitomeya imitator, a species that has undergone a Müllerian mimetic radiation to establish four morphs in Peru. We find that mimetic morphs are strongly phenotypically differentiated, producing geographic clines with varying widths. However, distinct morphs show little neutral genetic divergence, and landscape genetic analyses implicate isolation by distance as the primary determinant of among-population genetic differentiation. Mate choice experiments suggest random mating at the transition zones, although certain allopatric populations show a preference for their own morph. We present evidence that this preference may be mediated by color pattern specifically. These results contrast with an earlier study of a third transition zone, in which a mimetic shift was a...

13 May 2020 in Molecular Ecology
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ETEvan Twomey
Evan Twomey
JJJames D. Johnson
James D. Johnson
SCSantiago Castroviejo‐Fisher
Santiago Castroviejo‐Fisher
IBInes Van Bocxlaer
Ines Van Bocxlaer


1 December 2015 in Herpetologica
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Journal Article
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ETEvan Twomey
Evan Twomey
MMMichael Mayer
Michael Mayer
KSKyle Summers
Kyle Summers
Calls are important premating isolating barriers in frogs; therefore, studying intraspecific variation in calls might allow the assessment of patterns of call divergence during the early stages of speciation. Ranitomeya imitator, a species of dart-poison frog (Dendrobatidae), has undergone extensive color-pattern diversification through a Müllerian mimetic radiation, establishing four distinct morphs in north-central Peru (striped, banded, varadero, and spotted). Partial reproductive isolation exists between certain color morphs, although the specific mechanisms responsible for this isolation are poorly understood. We conducted a species-wide analysis of variation in advertisement calls to investigate whether distinct mimetic morphs show advertisement call differences. We found that different color morphs generally show weak or no differences in advertisement calls, with two exceptions. First, call pulse rates differed between the striped and banded morphs, and that difference coincides geograp...

28 May 2021 in Zootaxa
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Journal Article
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MRMauricio Rivera-Correa
Mauricio Rivera-Correa
DBDiego MICAELA Baldo
Diego MICAELA Baldo
FCFlorencia Vera Candioti
Florencia Vera Candioti
VOVictor Goyannes Dill Orrico
Victor Goyannes Dill Orrico
DBDavid C. Blackburn
David C. Blackburn
MVMiguel Vences
Miguel Vences
Zootaxa is a mega-journal that since its inception, 20 years ago, has contributed to the documentation of the planet’s biodiversity. Its role concerning terrestrial vertebrates has been crucial especially for amphibians, which are the most threatened class of vertebrates. As current editors of the Amphibia section, we reviewed the state of knowledge of taxonomic publications on amphibians over the last two decades (from 2001 to 2020). Our review reveals that 2,533 frogs, 259 salamanders, and 55 caecilians have been named in these 20 years, mainly in the tropical regions of South America, Asia, and Africa. More than half (57%) of these species descriptions were published in only 10 journals. At least 827 species of the new amphibians (29% of the total) were described in Zootaxa. This mega-journal has served also as a place of publication for monographs and systematic reviews, in addition to short articles documenting the vocalizations of anurans and the morphology of embryos and larvae. Its efficient evaluation process, the freedom of manuscript length, including full-color figures, and free of cost for the authors, has made Zootaxa a favorite for amphibian researchers. In an era of accelerating rates of biodiversity loss, documenting, describing, naming, and proposing evolutionary scenarios for species is, more than ever, an urgent task.