Salazar Valenzuela, David
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Preferred name
Salazar Valenzuela, David
Main Affiliation
Quito
Email
davidsalazar@uti.edu.ec
ORCID
Scopus Author ID
26644312900

Research Output
Now showing 1 - 10 of 27
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Online toolkits for collaborative and inclusive global research in urban evolutionary ecology

2024 , Amy M. Savage , Meredith J. Willmott , Pablo Moreno‐García , Zuzanna Jagiello , Daijiang Li , Anna Malesis , Lindsay S. Miles , Cristian Román‐Palacios , Salazar Valenzuela, David , Brian C. Verrelli , Kristin M. Winchell , Marina Alberti , Bonilla Bedoya, Santiago , Elizabeth Carlen , Cleo Falvey , Lauren Johnson , Ella Martin , Hanna Kuzyo , John Marzluff , Jason Munshi‐South , Megan Phifer‐Rixey , Ignacy Stadnicki , Marta Szulkin , Yuyu Zhou , Kiyoko M. Gotanda

Urban evolutionary ecology is inherently interdisciplinary. Moreover, it is a field with global significance. However, bringing researchers and resources together across fields and countries is challenging. Therefore, an online collaborative research hub, where common methods and best practices are shared among scientists from diverse geographic, ethnic, and career backgrounds would make research focused on urban evolutionary ecology more inclusive. Here, we describe a freely available online research hub for toolkits that facilitate global research in urban evolutionary ecology. We provide rationales and descriptions of toolkits for: (1) decolonizing urban evolutionary ecology; (2) identifying and fostering international collaborative partnerships; (3) common methods and freely-available datasets for trait mapping across cities; (4) common methods and freely-available datasets for cross-city evolutionary ecology experiments; and (5) best practices and freely available resources for public outreach and communication of research findings in urban evolutionary ecology. We outline how the toolkits can be accessed, archived, and modified over time in order to sustain long-term global research that will advance our understanding of urban evolutionary ecology.

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Venom versatility: Dynamic anticoagulant and procoagulant variations between and within Bothrocophias (toad-head) and basal Bothrops (lance-head) pit vipers

2025 , Lachlan A. Bourke , Salazar Valenzuela, David , Marco Mancuso , Diego R. Quirola , Amaru Loaiza-Lange , Christina N. Zdenek , Matthew R. Lewin , Ernesto Arbeláez-Ortiz , Bryan G. Fry

Pinpointing the emergence of toxicological evolutionary novelties can be challenging. In American pit vipers, anticoagulant venoms are the paradigm, with a notable exception being the genus Bothrops, which are typically procoagulant. A recent study found that the basal Bothrops (B. pictus) is anticoagulant, raising two competing hypotheses: ancestral Bothrops were anticoagulant with procoagulant venom evolving later, or ancestral Bothrops were procoagulant with anticoagulant venom in B. pictus being a derived trait. To help resolve this, we tested venoms of the sister genus Bothrocophias for pathophysiological actions upon blood clotting. The Ecuadorian Bothrocophias venoms (B. campbelli, B. lojanus, and B. microphthalmus) were compared to Bothrops pictus. Both Bothrocophias lojanus and B. pictus inhibited various blood clotting enzymes, but B. pictus was more potently anticoagulant. Intriguingly, B. campbelli and B. microphthalmus were procoagulant. Both B. microphthalmus populations activated prothrombin, but Zamora Chinchipe locality also activated Factors X and VII. Bothrocophias campbelli showed a novel activity, using Factor Va in a calcium-dependent manner as a cofactor to activate prothrombin, the first time this has been shown for any viperid venom. Organismal phylogenetics failed to resolve the relative positions of B. campbelli and B. lojanus, thus we were unable to ascertain the ancestral trait. To resolve this, more phylogenetic research and venom testing with other Bothrocophias species is needed. Neutralisation tests revealed differential efficacy of PoliVal-ICP (Instituto Clodomiro Picado) and Soro Antibotrópico (Instituto Butantan) antivenoms. Together, these findings aid in designing evidence-based clinical-management strategies and provide foundational data for reconstructing venom evolution

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Neotropics as a Cradle for Adaptive Radiations

2025 , Juan E. Guevara-Andino , Liliana M. Dávalos , Felipe Zapata , María José Endara , Darko D. Cotoras , Jaime Chaves , Santiago Claramunt , Julia López-Delgado , Angela M. Mendoza-Henao , Salazar Valenzuela, David , Gonzalo Rivas-Torres , Justin Yeager

Neotropical ecosystems are renowned for numerous examples of adaptive radiation in both plants and animals resulting in high levels of biodiversity and endemism. However, we still lack a comprehensive review of the abiotic and biotic factors that contribute to these adaptive radiations. To fill this gap, we delve into the geological history of the region, including the role of tectonic events such as the Andean uplift, the formation of the Isthmus of Panama, and the emergence of the Guiana and Brazilian Shields. We also explore the role of ecological opportunities created by the emergence of new habitats, as well as the role of key innovations, such as novel feeding strategies or reproductive mechanisms. We discuss different examples of adaptive radiation, including classic ones like Darwin's finches and Anolis lizards, and more recent ones like bromeliads and lupines. Finally, we propose new examples of adaptive radiations mediated by ecological interactions in their geological context. By doing so, we provide insights into the complex interplay of factors that contributed to the remarkable diversity of life in the Neotropics and highlight the importance of this region in understanding the origins of biodiversity.

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A new species of harlequin toad (Bufonidae: Atelopus) from Amazonian Ecuador

2024 , Plewnia, Amadeus , Terán-Valdez, Andrea , Culebras, Jaime , Boistel, Renaud , Paluh, Daniel , Quezada Riera, Amanda B. , Heine, Christopher H , Reyes-Puig, Juan , Salazar Valenzuela, David , Guayasamin, Juan Manuel

For nearly four decades, harlequin toads, genus Atelopus, have suffered unparalleled population declines. While this also results in limited understanding of alphataxonomic relationships, these toads face an urgent need for advances in systematics to inform conservation efforts. However, high intraspecific variation and cryptic diversity have hindered a comprehensive understanding of Atelopus diversity. This is particularly exemplified among Amazonian populations related to A. spumarius, where decades of taxonomic work have not been able yet to unravel relationships between the many forms, while the names coined so far have led to taxonomic confusion leaving numer-ous lineages unnamed. A recent comprehensive phylogenetic study has revealed new insights into the systematics of harlequin toads with an emphasis on Amazonian forms, identifying several unnamed lineages. We here describe one of these evolutionary lineages as a new species, restricted to the Ecuadorian Amazon basin, in an integrative taxonomic approach using molecular, morphological, bioacoustic and larval information. With this, we contribute to a better understanding of Atelopus diversity as the baseline of conservation action.

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A new species of harlequin toad (Bufonidae: Atelopus) from Amazonian Ecuador

2024 , Plewnia, Amadeus , Terán-Valdez, Andrea , Culebras, Jaime , Boistel, Renaud , Paluh, Daniel J. , Quezada Riera, Amanda B. , Salazar Valenzuela, David , Guayasamin, Juan Manuel

For nearly four decades, harlequin toads, genus Atelopus, have suffered unparalleled population declines. While this also results in limited understanding of alphataxonomic relationships, these toads face an urgent need for advances in systematics to inform conservation efforts. However, high intraspecific variation and cryptic diversity have hindered a comprehensive understanding of Atelopus diversity. This is particularly exemplified among Amazonian populations related to A. spumarius, where decades of taxonomic work have not been able yet to unravel relationships between the many forms, while the names coined so far have led to taxonomic confusion leaving numer-ous lineages unnamed. A recent comprehensive phylogenetic study has revealed new insights into the systematics of harlequin toads with an emphasis on Amazonian forms, identifying several unnamed lineages. We here describe one of these evolutionary lineages as a new species, restricted to the Ecuadorian Amazon basin, in an integrative taxonomic approach using molecular, morphological, bioacoustic and larval information. With this, we contribute to a better understanding of Atelopus diversity as the baseline of conservation action.

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Harlequin frog rediscoveries provide insights into species persistence in the face of drastic amphibian declines

2022 , Jaynes, K.E. , Páez-Vacas, M.I. , Salazar Valenzuela, David , Guayasamin, J.M. , Terán-Valdez, A. , Siavichay, F.R. , Fitzpatrick, S.W.

Amphibians face global declines, and it remains unclear the extent to which species have responded, and through what mechanisms, to persist in the face of emerging diseases and climate change. In recent years, the rediscovery of species considered possibly extinct has sparked public and scientific attention. These are hopeful cases in an otherwise bleak story. Yet, we know little about the population status of these rediscovered species, or the biology underlying their persistence. Here, we highlight the iconic Harlequin frogs (Bufonidae: Atelopus) as a system that was devastated by declines but now encompasses between 18 and 32 rediscoveries (25–37 % of possible extinctions) in the last two decades. Geographic distributions of rediscoveries closely match regional described species abundance, and rediscoveries are documented at elevations from 100 m to >3500 m, with no significant differences between mean historical and contemporary elevations. We also provide genomic data on six decimated species, with historical sample comparisons for two of the species and find a pattern of decreasing genetic variation the longer a species had been missing. Further, we document marked decrease in heterozygosity in one species, but not the other, indicating potential idiosyncratic consequences of declines. Finally, we discuss research priorities to guide the potential transition from amphibian declines to recoveries and to maximize conservation efforts. © 2022 The Authors

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Bothrops atrox from Ecuadorian Amazon: Initial analyses of venoms from individuals

2021 , Patiño R.S.P. , Salazar Valenzuela, David , Medina-Villamizar E. , Mendes B. , Proaño-Bolaños C. , da Silva S.L. , Almeida J.R.

Bothrops atrox is the most clinically relevant snake species within the Amazon region, which includes Ecuadorian territories. It comprises a large distribution, which could contribute to the genetic and venomic variation identified in the species. The high variability and protein isoform diversity of its venom are of medical interest, since it can influence the clinical manifestations caused by envenomation and its treatment. However, in Ecuador there is insufficient information on the diversity of venomic phenotypes, even of relevant species such as B. atrox. Here, we characterized the biochemical and toxicological profiles of the venom of six B. atrox individuals from the Ecuadorian Amazon. Differences in catalytic activities of toxins, elution profiles in liquid chromatography, electrophoretic patterns, and toxic effects among the analyzed samples were identified. Nonetheless, in the preclinical testing of antivenom, two samples from Mera (Pastaza) required a higher dose to achieve total neutralization of lethality and hemorrhage. Taken together, these data highlight the importance of analyzing individual venoms in studies focused on the outcomes of envenoming. © 2021 Elsevier Ltd

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Evaluating the utility of camera traps in field studies of predation

2019 , Akcali C.K. , Pérez-Mendoza H.A. , Salazar Valenzuela, David , Kikuchi D.W. , Guayasamin, Juan M. , Pfennig D.W.

Artificial prey techniques-wherein synthetic replicas of real organisms are placed in natural habitats-are widely used to study predation in the field.We investigated the extent to which videography could provide additional information to such studies. As a part of studies on aposematism and mimicry of coral snakes (Micrurus) and their mimics, observational data from 109 artificial snake prey were collected from video-recording camera traps in three locations in the Americas (terra firme forest, Tiputini Biodiversity Station, Ecuador; premontane wet forest, Nahá Reserve, Mexico; longleaf pine forest, Southeastern Coastal Plain, North Carolina, USA). During 1,536 camera days, a total of 268 observations of 20 putative snake predator species were recorded in the vicinity of artificial prey. Predators were observed to detect artificial prey 52 times, but only 21 attacks were recorded. Mammals were the most commonly recorded group of predators near replicas (243) and were responsible for most detections (48) and attacks (20). There was no difference between avian or mammalian predators in their probability of detecting replicas nor in their probability of attacking replicas after detecting them. Bite and beak marks left on clay replicas registered a higher ratio of avian:mammalian attacks than videos registered. Approximately 61.5% of artificial prey monitored with cameras remained undetected by predators throughout the duration of the experiments. Observational data collected from videos could provide more robust inferences on the relative fitness of different prey phenotypes, predator behavior, and the relative contribution of different predator species to selection on prey. However, we estimate that the level of predator activity necessary for the benefit of additional information that videos provide to be worth their financial costs is achieved in fewer than 20% of published artificial prey studies. Although we suggest future predation studies employing artificial prey to consider using videography as a tool to inspire new, more focused inquiry, the investment in camera traps is unlikely to be worth the expense for most artificial prey studies until the cost:benefit ratio decreases. © 2019 PeerJ Inc. All rights reserved.

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A roadmap for harlequin frog systematics, with a partial revision of Amazonian species related to Atelopus spumarius

2025 , STEFAN LÖTTERS , PHILIPP BÖNING , SALVADOR BAILON , JOSE DANIEL BARROS CASTAÑEDA , RENAUD BOISTEL , ALESSANDRO CATENAZZI , JUAN C. CHAPARRO , GERMÁN CHÁVEZ , ANGEL CHUJUTALLI , LAURENT COEN , LUIS A. COLOMA , ANDREW J. CRAWFORD , JAIME CULEBRAS , JUAN CARLOS CUSI MARTÍNEZ , JUAN MANUEL DAZA , IGNACIO DE LA RIVA , DENISE J. ELLWEIN , RAFFAEL ERNST , SANDRA V. FLECHAS , ANTOINE FOUQUET , JUAN MANUEL GUAYASAMIN , CHRISTOPHER HEINE , RAFAEL F. JORGE , ALISHA JUNG , KARL-HEINZ JUNGFER , NATHALIE KAFFENBERGER , HENRIK KREHENWINKEL , ENRIQUE LA MARCA , MARGARITA LAMPO , GUIDO F. MEDINA RANGEL , LUDVIG ORSEN , DANIEL J. PALUH , JOSÉ LUIS PÉREZ GONZALEZ , JONATHAN PERRIN , AMANDA B. QUEZADA RIERA , JUAN PABLO REYES-PUIG , BERNARDO ROCA-REY ROSS , DANIELA C. RÖSSLER , LUIS ALBERTO RUEDA SOLANO , Salazar Valenzuela, David , JOSEFA CELSA SEÑARIS VAZQUEZ , MORGANE SOWINSKI , ANDREA TERÁN-VALDEZ , ANGIE TOVAR-ORTIZ , MICHAEL VEITH , PABLO VENEGAS , RUDOLF VON MAY , TIMM WEITKAMP , AMADEUS PLEWNIA

Harlequin frogs, genus Atelopus, are a species-rich group of bufonid anurans from the Neotropics with more than 100 species. For nearly four decades now, this group has suffered from massive population declines. Almost all species are threatened with extinction, and many populations and several species are considered extinct or possibly extinct. This results in a limited sampling available for studies on harlequin frog systematics, especially in terms of molecular genetic information. However, efficient conservation of harlequin frogs requires an improved taxonomy. This is further complicated through the circumstance that many Atelopus species are relatively poor in external morphological characters combined with a high level of intra-specific character variation (e.g. coloration and body size). At the same time, cryptic diversity exists with well differentiated species (supported by osteology and molecular genetics) almost indistinguishable by external morphology. We compiled the largest dataset to date for mitochondrial (12S, 16S, cyt b) and nuclear (POMC, RAG1) markers and present a phylogeny (likelihood and Bayesian inference methods) including 152 samples from 104 populations scattered over the entire geographic range of the genus. Four allo- or parapatric main clades are distinguished: I. Sierra Nevada; II. Venezuelan-Andean; III. Andean-Chocó-Central American (with the ignescens and the varius-longirostris clades); and IV Amazonian (containing the tricolor and the flavescens-spumarius clades). The phylogenetic relationships within these clades remain to be resolved. Taxonomic implications included both splitting and lumping, but taxonomic action is here only taken for populations related to A. spumarius from western Amazonia. Besides redescriptions of A. spumarius sensu stricto and A. colomai, we describe two new species based on morphology, skull osteology and bioacoustics. Additional yet understudied populations from Amazonia may be allocated to these species or may represent additional undescribed taxa.

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A new species of pitviper of the genus Bothrops (Serpentes: Viperidae: Crotalinae) from the Central Andes of South America

2019 , Timms J. , Chaparro J.C. , Venegas P.J. , Salazar Valenzuela, David , Scrocchi G. , Cuevas J. , Leynaud G. , Carrasco P.A.

We describe a new species of montane pitviper of the genus Bothrops from the Cordillera Oriental of the Central Andes, distributed from southern Peru to central Bolivia. The new species can be distinguished from its congeners by the characteristic combination of a dorsal body color pattern consisting of triangular or subtriangular dark brown dorsal blotches, paired dark brown parallel occipital stripes, a conspicuous dark brown postocular stripe, the presence of canthorostrals in some specimens, prelacunal fused or partially fused with second supralabial, one scale usually separating internasals, rostral trapezoidal, two canthals oval to rounded, similar size or slightly larger than internasals, three or four medial intercanthals, eight to twelve intersupraoculars, intercanthals and intersupraoculars keeled and frequently slightly keeled, supraoculars oval, one to three suboculars, two to three postoculars, loreal subtriangular, two to six prefoveals, subfoveals absent, two or none postfoveals, one or two scales between suboculars and fourth supralabial, seven or eight supralabials, nine or eleven infralabials, 23-25 middorsal scales, 189-195 ventrals in females and 182-190 in males, 48-58 subcaudals in females and 54-63 in males, exceptionally undivided. The new species is apparently restricted to areas within Andean montane forests that are less humid and devoid of large trees. Copyright © 2019 Magnolia Press.

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