Browsing by Author "Ron Melo, Santiago Rafael"
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Item Open Access A bizarre new species of Lynchius (Amphibia, Anura, Strabomantidae) from the Andes of Ecuador and first report of Lynchius parkeri in Ecuador(2019) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelWe describe a new species of Lynchius from the eastern montane forest of southern Ecuador. We also report the occurrence of L. parkeri in Ecuador, on paramos of Yacuri National Park, near the border with Peru. We used morphological and genetic evidence for the description of the new species and the new report of L. parkeri. Phylogenetic analyses were carried out using both maximum likelihood and Bayesian inference on DNA sequences for mitochondrial and nuclear genes. The phylogeny shows that L. simmonsi is sister to a clade composed of the remaining species of Lynchius and that the new species is sister to L. flavomaculatus. The new species has a prominent and heavily ossified head with noticeably spiculate cranial exostosis that easily distinguishes it from all its congeners. The dorsal region and limbs present several reduced subconical and rounded tubercles and pronounced dermal ridges on the dorsum. We also describe the osteology of the new species based on x-rays of the holotype. Only six species of Lynchius, two known to occur in Ecuador (L. flavomaculatus and L. simmonsi). The description of L. megacephalus sp. n. and new record of L. parkeri double the number of known Lynchius in Ecuador and suggest that the diversity of Ecuadorian and Peruvian Lynchius is still underestimated.Item Open Access A new cryptic species of the Pristimantis lacrimosus group (Anura, Strabomantidae) from the eastern slopes of the Ecuadorian Andes(2021-07-23) Carrión Olmedo, Julio Cësar; Ron Melo, Santiago Rafael; Carrión Olmedo, Julio César y Ron Melo, Santiago RafaelWith 566 species, the neotropical genus Pristimantis is the most speciose vertebrate genus. As a result of its striking diversity, taxonomic reviews remain a challenge. Herein, we present an updated phylogeny of the Pristimantis lacrimosus group and describe a new species from Llanganates and Sangay National Parks. We also report, for the first time, the phylogenetic position of Pristimantis degener, P. eugeniae, P. katoptroides, and P. petersi. Based on our phylogeny, we add two species to the Pristimantis lacrimosus group. Through the integration of molecular and bioacoustic evidence, we describe a new species which was hidden under “Pristimantis petersi”. Pristimantis petersioides sp. nov. is most closely related to Pristimantis petersi and an undescribed species from Peru. It can be distinguished from P. petersi by its advertisement call and large genetic differences (uncorrected p-genetic distances 7.9% to 8.4% for gene 16S). Moreover, the new species and P. petersi are not sister species. We suggest assigning the new species to the Endangered Red List category because it has a small distribution range with deforestation as result of agriculture and other anthropogenic influences.Item Open Access A new species of direct-developing frog of the genus Pristimantis (Anura: Terrarana: Craugastoridae) from Cordillera del Cóndor, Ecuador, with comments on threats to the anuran fauna of the region(2017) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelA new frog in the genus Pristimantis is described from a cloud forest on the western flanks of the Cordillera del Cóndor and eastern Andean slopes in the province of Zamora Chinchipe, southeastern of Ecuador. We inferred its phylogenetic position using DNA sequences of mitochondrial and nuclear genes. The new species is strongly supported as part of a clade that includes P. ardalonychus, P. cajamarcensis, P. ceuthospilus, P. chalceus, P. minutulus, P. luteolateralis, P. parvillus, P. ockendeni, P. unistrigatus, and P. walkeri. It can be distinguished from all other species from Cordillera del Cóndor and congeneric species by the unique combination of the following characters: (1) iris light blue with black reticulations; (2) skin of dorsum finely shagreen with scattered pustular tubercles and absence of dorsal folds; (3) tympanic membrane and tympanic annulus visible; (4) snout rounded in dorsal and lateral view; (5) upper eyelid bearing two or three enlarged subconical tubercles; (6) cranial crest absent; (7) males lacking vocal sac and slits; and (8) venter uniformly bright red, light red, salmon or orange. The new species is most closely related to P. ardalonychus, P. cajamarcensis, P. ceuthospilus, P. ockendeni and P. unistrigatus. We consider the new species to be Endangered following IUCN criteria because it has been severely affected by large scale open-pit mining in some localities. Currently, the amphibian fauna of the Cordillera del Cóndor and nearby protected areas are threatened by large–scale copper and gold mining projects with devastating effects on ~20 species, including several undescribed ones.Item Open Access A new species of Engystomops (Anura: Leiuperidae) from southwestern Ecuador(2010) Ron Melo, Santiago Rafael; Ron, Santiago R.We describe Engystomops puyango sp. nov. from the lowlands of southwestern Ecuador. The new species is closely related to E. pustulatus from which it differs in skin texture, advertisement call, and karyotype features. The new species also differs from E. pustulatus at genes 12S and 16S of mitochondrial DNA (6.5%–6.8% of sequence divergence). A phylogeny based on mtDNA shows that E. sp. nov. is part of a clade of Engystomops distributed below 1300 m in western Ecuador and northwestern Peru. The new species occurs in Evergreen Lower Montane Forest and Foothill Semideciduous Costa Forest. The karyotype of the new species has 2n = 20 chromosomes which represents the first known reduction in chromosome number in Leiuperidae (2n = 22). Its advertisement calls as well as those of E. pustulatus have a facultative component that resembles the chuck in calls of E. pustulosus but that are less discrete and have lower acoustic complexity.Item Open Access A new species of terrestrial frog of the genus Noblella Barbour, 1930 (Amphibia: Strabomantidae) from the Llanganates-Sangay Ecological Corridor, Tungurahua, Ecuador(2019-08-12) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelWe describe a new species of terrestrial frog of the genus Noblella from the eastern versantsoftheEcuadorianAndesintheupperPastazawatershed.Noblellanaturetrekii sp. n. differs from its Ecuadorian congeners by the presence of a differentiated tympanic membrane and a weakly defined tympanic annulus, and eyelids with rounded tubercles. In addition, the new species is characterized by its blackish–dark brown ventral coloration scattered with little white dots and the absence of papillae at the tip of the fingers and toes. We provide a detailed description of the call and osteology of the new species. Finally, we present the most complete phylogeny of the genus, which confirms that Noblella is a non-monophyletic group.Item Open Access A new species of terrestrial frog Pristimantis (Strabomantidae) from the upper basin of the Pastaza River, Ecuador(2019-03-19) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelWe describe a new species of Pristimantis from the montane forest of the Río Zuñag Ecological Reserve, upper basin of the Pastaza River, Ecuador. Pristimantis mallii sp. n. is characterized by a snout-vent length of 11.6–21.3 mm in adult males (n = 12), 22.6–34.3 mm in adult females (n = 8), and is compared morphologically and genetically with Pristimantis miktos and with other relevant species of Pristimantis. The new species is characterized by having skin on dorsum and flanks shagreen, distinctive scapular folds, snout broadly rounded in dorsal view, upper eyelid bearing one or two subconical tubercles and some rounded tubercles, dorsum and flanks light brown to brown, with irregular dark brown marks bounded by dirty cream and groin with irregular yellowish marks.Item Open Access A new treefrog from Cordillera del Cóndor with comments on the biogeographic affinity between Cordillera del Cóndor and the Guianan Tepuis (Anura, Hylidae, Hyloscirtus)(2018-12) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelThe Hyloscirtus larinopygion group is a clade of 16 species of large hylids that inhabit cascading Andean streams. They have brown coloration that, in most species, contrasts with bright marks. Herein morphological and genetic evidence is used to describe a new species of the group from Cordillera del Cóndor, a sub-Andean mountain chain that has phytogeographic affinities with the Guianan Tepuis. The new species is characterized by dark-brown coloration with contrasting bright orange flecks and by the presence of an enlarged and curved prepollex protruding as a spine. The new species is closely related to H. tapichalaca and an undescribed species from the southern Andes of Ecuador. The genetic distance between H. hillisi sp. n. and its closest relative, H. tapichalaca, is 2.9% (gene 16S mtDNA). Our phylogeny and a review of recently published phylogenies show that amphibians from Cordillera del Cóndor have close relationships with either Andean or Amazonian species. Amphibians do not show the Condor-Guianan Tepuis biogeographic link that has been documented in plants.Item Open Access A Pan-Amazonian species delimitation: high species diversity within the genus Amazophrynella (Anura: Bufonidae)(2018-07) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelAmphibians are probably the most vulnerable group to climate change and climatechange associate diseases. This ongoing biodiversity crisis makes it thus imperative to improve the taxonomy of anurans in biodiverse but understudied areas such as Amazonia. In this study, we applied robust integrative taxonomic methods combining genetic (mitochondrial 16S, 12S and COI genes), morphological and environmental data to delimit species of the genus Amazophrynella (Anura: Bufonidae) sampled from throughout their pan-Amazonian distribution. Our study confirms the hypothesis that the species diversity of the genus is grossly underestimated. Our analyses suggest the existence of eighteen linages of which sevenare nominal species, three Deep Conspecific Lineages ,one Unconfirmed Candidate Species, three Uncategorized Lineages, and four Confirmed Candidate Species and described herein. We also propose a phylogenetic hypothesis for the genus and discuss its implications for historical biogeography of this Amazonian group.Item Open Access A polymorphism in oocyte pigmentation in natural populations of the glass frog Espadarana prosoblepon (Centrolenidae)(2021) Romero Carvajal, Marco Andrés; Ron Melo, Santiago Rafael; Romero Carvajal, Marco Andrés y Ron Melo, Santiago RafaelThe adaptive role of amphibian oocyte melanic pigmentation and its molecular control are still elusive. Here we present evidence of a polymorphism in egg pigmentation in the emerald glass frog Espadarana prosoblepon. In Ecuadorian natural populations of this species, females can lay dark brown or pale eggs that develop into normal pigmented tadpoles and adults. This trait is a sex-limited phenotype which is inherited like a recessive allele that we called pale eggs like (pel). The pel phenotype is exclusive of oocyte cortical melanic pigmentation, which is reduced in comparison to wild type (wt) dark pigmented oocytes. Consequently, pel early embryos are paler in appearance, with reduced melanic pigmentation distributed to early blastomeres and embryonic ectoderm. However, these embryos form normal melanocyte derived pigmentation. Finally, we discuss the origin of this polymorphism and propose the use of E. prosoblepon as a model to study the adaptive role of egg pigmentation.Item Open Access Advertisement calls and DNA sequences reveal a new species of Scinax (Anura: Hylidae) on the Pacific lowlands of Ecuador(2018-09) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelScinax is a speciose genus of Neotropical hylid frogs. We describe a new species from western Ecuador (elevations between 0 and 1207 m) using morphology, vocalizations, and DNA sequences. We also present a new phylogeny for Scinax based on mitochondrial DNA genes 12S rRNA, Cytochrome Oxidase sub-unit I, Cytochrome B, 16S rRNA, NADH dehydrogenase subunit 1, and adjacent tRNAs. The new species, Scinax tsachila sp. nov. was previously confused with S. quinquefasciatus, a morphologically similar sympatric species. They differ by having markedly different advisement calls, distinct skin texture in the dorsum, and different bone coloration. The new species is sister to S. elaeochroa, a species that differs in advertisement call and color pattern. We provide an updated species account for Scinax quinquefasciatus and a redescription of its holotype.Item Open Access Amphibians and reptiles of Wildsumaco Wildlife Sanctuary, Napo Province, Ecuador(2021-05) Ron Melo, Santiago Rafael; Ron Melo, Santiago Rafael y Torres Carvajal, Lenin OmarWe conducted a long-term inventory of the herpetofauna of Wildsumaco Wildlife Sanctuary in the eastern part of the Napo Province in Ecuador. This private preserve is about 500 ha in size and is located on the southern slopes of Volcán Sumaco. The preserve contains primary forest, secondary forest, and pasture habitats. Based mostly on nocturnal transect sampling we documented 39 species of amphibians including one species of salamander, two species of caecilians, and 36 species of frogs. Rain frogs (Pristimantis Jiminez de la Espada, 1871) were diverse with 14 species documented. A diverse species assemblage of 45 reptile species was also documented on the preserve. Six amphibian species found were listed by the IUCN Red List. At least three species exhibited substantial geographic range extensions and seven species showed elevational range extensions. We discovered several undescribed species including one salamander, three frogs, one lizard, and one snake.Item Open Access Ancient tepui summits harbor young rather than old lineages of endemic frogs.(2012) Ron Melo, Santiago Rafael; Salerno, Patricia E.The flattop mountains (tepuis) of South America are ancient remnants of the Precambrian Guiana Shield plateau. The tepui summits, isolated by their surrounding cliffs that can be up to 1000 m tall, are thought of as “islands in the sky,” harboring relict flora and fauna that underwent vicariant speciation due to plateau fragmentation. High endemicity atop tepui summits support the idea of an ancient “Lost World” biota. However, recent work suggests that dispersal between lowlands and summits has occurred long after tepui formation indicating that tepui summits may not be as isolated from the lowlands as researchers have long suggested. Neither view of the origin of the tepui biota (i.e., ancient vicariance vs. recent dispersal) has strong empirical support owing to a lack of studies. We test diversification hypotheses of the Guiana Shield highlands by estimating divergence times of an endemic group of treefrogs, Tepuihyla. We find that diversification of this group does not support an ancient origin for this taxon; instead, divergence times among the highland species are 2–5 Ma. Our data indicate that most highland speciation occurred during the Pliocene. Thus, this unparalleled landscape known as “The Lost World” is inhabited, in part, not by Early Tertiary relicts but neoendemics.Item Open Access Changes in Population Size and Survival in Atelopus spumarius (Anura: Bufonidae) are not Correlated with Chytrid Prevalence.(2014) Ron Melo, Santiago Rafael; Tarvin, RebeccaAproximadamente un tercio de las especies de anfibios experimentan declives poblacionales. Entre los grupos más afectados están las ranas Arlequín (Bufonidae: Atelopus), casi todas se encuentran en peligro de extinción. Monitoreamos el tamaño poblacional y la supervivencia de una de las últimas poblaciones ecuatorianas de Atelopus spumarius con un muestreo de marca-recaptura entre Febrero 2009 y Diciembre 2010. Debido a que Batrachochytrium dendrobatidis (Bd) había sido previamente registrado en el sitio, quisimos determinar su efecto en el tamaño poblacional y supervivencia. También analizamos el efecto de tala selectiva, la cual ocurrió a lo largo del transecto en Abril 2010. Diagnosticamos la presencia de Bd en cada individuo capturado o recapturado usando PCR de punto final. Las 679 muestras de Bd (provenientes de 356 individuos) fueron negativas, sugiriendo que Bd no influenció el tamaño poblacional y la supervivencia. El tamaño poblacional aumentó durante los nueve primeros meses del estudio (julio 2009–abril 2010) de un estimado de 47 a 92 individuos pero luego disminuyó en noviembre de 2010 a 48 individuos. La probabilidad de supervivencia fue 0.13 más baja en los meses posteriores a la tala selectiva que en los meses previos; emigración también disminuyó por 0.37 en los últimos meses. Parejas en amplexus fueron encontradas entre abril y diciembre, sugiriendo un período reproductivo largo, o incluso de duración anual. Aunque la mayoría de declives de Atelopus han sido atribuidos a infecciones de Bd, presentamos un caso en el que Bd ha sido detectado en el área, pero los cambios en el tamaño de la población no pueden ser atribuidos a quitridiomicosis. Análisis de supervivencia y del índice de la condición corporal en machos sugiere que el declive al final del estudio fue resultado de la destrucción del hábitat.Item Metadata only Description and phylogenetic relationships of a new species of treefrog of the Osteocephalus buckleyi species group (Anura: Hylidae)(2020-02) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelThe Osteocephalus buckleyi species group is widely distributed in primary and secondary forests of the Amazon Basin and Guiana Region. Based on integrative analysis, including morphological and genetic data, we estimate the phylogenetic relationships and species boundaries among populations of the Osteocephalus buckleyi group from the Ecuadorian Amazon, focusing on the O. verruciger-O. cannatellai species complex. Our results uncovered the existence of one confirmed candidate species from Sangay National Park and one unconfirmed candidate species. Here, we describe the new species which is morphologically and ecologically distinct from other Osteocephalus species. The new species is unusual because it shows quite distinct morphology, but low genetic distances compared to its closest relatives.Item Metadata only Description and phylogenetic relationships of a new trans-Andean species of Elachistocleis Parker 1927 (Amphibia, Anura, Microhylidae)(2020-05) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelElachistocleis is a Neotropical genus of microhylid frogs with 18 species, most of which occur east of the Andes in South America. Here, we present a new phylogeny of Gastrophryninae and describe and name a new species of Elachistocleis from southern Ecuador—the first to be found west of the Andes and also the first from Ecuador. Our phylogeny is based on DNA sequences of the mitochondrial genes 12S rRNA, 16S rRNA, COI, and the nuclear genes BDNF, cmyc2, H3A, 28S, SIA1, and Tyr. Elachistocleis araios sp. n., is the sister species of all other Elachistocleis. The finding of this taxon highlights the probability of the existence of more Elachistocleis species west of the Andes.Item Open Access Description of a new species of glassfrog from “El Quimi” Reserve in the Cordillera del Condor (Anura, Centrolenidae, Nymphargus)(PUCE - Quito, 2023-05-01) Masache Sarango, Mylena Victoria; Ron Melo, Santiago RafaelWith 34 species, the genus Nymphargus is characterized by the absence of humeral spines among other characters. To differentiate between the species of this genus can be somewhat complex since you have to look at the details to identify cryptic species. In this study we present an updated phylogeny of the Nymphargus genus showing the new species and also the phylogenetic position of N. buenaventura for the first time. The new species is characterized by not having spots on the dorsum, shagreen skin and white esophagus and stomach. The new species is closely related to a couple of undescribed species.Item Open Access Discovering Hidden Diversity of Characins (Teleostei: Characiformes) in Ecuador’s Yasuní National Park(14/08/2015) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelManagement and conservation of biodiversity requires adequate species inventories. The Yasuní National Park is one of the most diverse regions on Earth and recent studies of terrestrial vertebrates, based on genetic evidence, have shown high levels of cryptic and undescribed diversity. Few genetic studies have been carried out in freshwater fishes from western Amazonia. Thus, in contrast with terrestrial vertebrates, their content of cryptic diversity remains unknown. In this study, we carried out genetic and morphological analyses on characin fishes at Yasuní National Park, in eastern Ecuador. Our goal was to identify cryptic diversity among one of the most speciose fish families in the Amazon region. This is the first time that genetic evidence has been used to assess the species content of the Napo Basin, one of the richest regions in vertebrate diversity. Results: Phylogenetic analyses of partial mitochondrial 16S ribosomal RNA gene (∼600 pb) DNA sequences from 232 specimens of the family Characidae and its closest groups revealed eight candidate new species among 33 species sampled, representing a 24% increase in species number. Analyses of external morphology allowed us to confirm the species status of six of the candidate species. Conclusions: Our results show high levels of cryptic diversity in Amazonian characins. If this group is representative of other Amazonian fish, our results would imply that the species richness of the Amazonian ichthyofauna is highly underestimated. Molecular methods are a necessary tool to obtain more realistic inventories of Neotropical freshwater fishes.Item Metadata only Disease reservoirs threaten the recently rediscovered Podocarpus Stubfoot Toad (Atelopus podocarpus)(2020) Merino Viteri, Andrés Ricardo; Ron Melo, Santiago Rafael; Merino Viteri, Andrés RicardoThe Andes have experienced an unprecedented wave of amphibian declines and extinctions that are linked to a combination of habitat reduction and the spread of the fungal pathogen, Batrachochytrium dendrobatidis (Bd). In the present study, a range of high-altitude habitats in Southern Ecuador were surveyed for the presence of Bd. With a particular focus on Yacuri National Park, infection data are presented from across the resident amphibian community. This community contains a once putatively extinct species which was rediscovered in 2016, the Podocarpus Stubfoot Toad (Atelopus podocarpus). Across species, local Bd prevalence was 73% in tadpoles (n = 41 individuals from three species) and 14% in adults (n = 43 individuals from 14 species). Strikingly, 93% (14/15) of tested tadpoles of the recently described local endemic, Gastrotheca yacuri, were infected with a high pathogen load, suggesting that this species likely acts as a reservoir of infection in Yacuri. These findings show that the threat of disease for A. podocarpus still exists, and that this species requires urgent action to ensure its survival.Item Metadata only Diversification history of clown tree frogs in Neotropical rainforests (Anura, Hylidae, Dendropsophus leucophyllatus group)(2020-09) Ron Melo, Santiago Rafael; Ron Melo, Santiago RafaelGeneral consensus emphasizes that no single biological process can explain the patterns of species’ distributions and diversification in the Neotropics. Instead, the interplay of several processes across space and time must be taken into account. Here we investigated the phylogenetic relationships and biogeographic history of tree frogs in the Dendropsophus leucophyllatus species group (Amphibia: Hylidae), which is distributed across Amazonia and the Atlantic rainforests. Using Next Generation Sequencing (NGS) and double digest restriction-site associated DNA (ddRADseq), we inferred phylogenetic relationships, species limits, and temporal and geographic patterns of diversification relative to the history of these biomes. Our results indicate that the D. leucophyllatus species group includes at least 14 independent lineages, which are currently arranged into ten described species. Therefore, a significant portion of species in the group are still unnamed. Different processes were associated to the group diversification history. For instance, the Andes uplift likely caused allopatric speciation for Cis-Andean species, whereas it may also be responsible for changes in the Amazonian landscape triggering parapatric speciation by local adaptation to ecological factors. Meanwhile, Atlantic Forest ancestors unable to cross the dry diagonal biomes after rainforest’s retraction, evolved in isolation into different species. Diversification in the group began in the early Miocene, when connections between Atlantic Forest and the Andes (Pacific Dominion) by way of a south corridor were possible. The historical scenario in Amazonia, characterized by several speciation events and habitat heterogeneity, helped promoting diversification, resulting in the highest species diversity for the group. This marked species diversification did not happen in Atlantic Forest, where speciation is very recent (late Pliocene and Pleistocene), despite its remarkable climatic heterogeneity.Item Open Access Ecological and genetic divergence between two lineages of Middle American túngara frogs Physalaemus (=Engystomops) pustulosus(2010) Ron Melo, Santiago Rafael; Pröhl, Heike.Uncovering how populations of a species differ genetically and ecologically is important for understanding evolutionary processes. Here we combine population genetic methods (microsatellites) with phylogenetic information (mtDNA) to define genetic population clusters of the wide-spread Neotropical túngara frog (Physalaemus pustulosus). We measure gene flow and migration within and between population clusters and compare genetic diversity between population clusters. By applying ecological niche modeling we determine whether the two most divergent genetic groups of the túngara frog (1) inhabit different habitats, and (2) are separated geographically by unsuitable habitat across a gap in the distribution. Most population structure is captured by dividing all sample localities into two allopatric genetic lineages. The Northern genetic lineage (NW Costa Rica) is genetically homogenous while the Southern lineage (SW Costa Rica and Panama) is sub-divided into three population clusters by both microsatellite and mtDNA analyses. Gene flow is higher within the Northern lineage than within the Southern lineage, perhaps due to increased landscape heterogeneity in the South. Niche modeling reveals differences in suitable habitat between the Northern and Southern lineages: the Northern lineage inhabits dry/pine-oak forests, while the Southern lineage is confined to tropical moist forests. Both lineages seem to have had little movement across the distribution gap, which persisted during the last glacial maximum. The lack of movement was more pronounced for the Southern lineage than for the Northern lineage. This study confirms the finding of previous studies that túngara frogs diverged into two allopatric genetic lineages north and south of the gap in the distribution in central Costa Rica several million years ago. The allopatric distribution is attributed to unsuitable habitat and probably other unknown ecological factors present across the distribution gap. Niche conservatism possibly contributes to preventing movements across the gap and gene flow between both groups. Genetic and ecological data indicate that there is the potential for ecological divergence in allopatry between lineages. In this context we discuss whether the Northern and Southern lineages should be recognized as separate species, and we conclude that further studies of pre- and post-zygotic isolation are needed for a final assessment. Identified population clusters should motivate future behavioral and ecological research regarding within-species biodiversity and speciation mechanisms.