Abstract
Shark fishing, driven by the fin trade, is the primary cause of global shark population declines. Here, we present a case study that exemplifies how industrial fisheries are likely depleting ...shark populations in the Eastern Tropical Pacific Ocean. In August 2017, the vessel Fu Yuan Yu Leng 999, of Chinese flag, was detained while crossing through the Galápagos Marine Reserve without authorization. This vessel contained 7639 sharks, representing one of the largest seizures recorded to date. Based on a sample of 929 individuals (12%), we found 12 shark species: 9 considered as Vulnerable or higher risk by the IUCN and 8 listed in CITES. Four species showed a higher proportion of immature than mature individuals, whereas size-distribution hints that at least some of the fishing ships associated with the operation may have been using purse-seine gear fishing equipment, which, for some species, goes against international conventions. Our data expose the magnitude of the threat that fishing industries and illegal trade represent to sharks in the Eastern Tropical Pacific Ocean.
Janzen's extension of the climate variability hypothesis (CVH) posits that increased seasonal variation at high latitudes should result in greater temperature overlap across elevations, and favour ...wider thermal breadths in temperate organisms compared to their tropical counterparts.
We tested these predictions by measuring stream temperatures and thermal breadths (i.e. the difference between the critical thermal maximum and minimum) of 62 aquatic insect species from temperate (Colorado, USA) and tropical (Papallacta, Ecuador) streams spanning an elevation gradient of c. 2000 m.
Temperate streams exhibited greater seasonal temperature variation and overlap across elevations than tropical streams, and as predicted, temperate aquatic insects exhibited broader thermal breadths than tropical insects. However, elevation had contrasting effects on patterns of thermal breadth. In temperate species, thermal breadth decreased with increasing elevation because CTMAX declined with elevation while CTMIN was similar across elevations. In tropical insects, by contrast, CTMAX declined less sharply than CTMIN with elevation, causing thermal breadth to increase with elevation.
These macrophysiological patterns are consistent with the narrower elevation ranges found in other tropical organisms, and they extend Janzen's CVH to freshwater streams. Furthermore, because lowland tropical aquatic insects have the narrowest thermal breadths of any region, they may be particularly vulnerable to short‐term extreme changes in stream temperature.
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DNA barcoding, based on mitochondrial markers, is widely applied in species identification and biodiversity studies. The aim of this study was to establish a barcoding reference database of fishes ...inhabiting the Cube River from Western Ecuador in the Chocó-Darien Global Ecoregion (CGE), a threatened ecoregion with high diversity and endemism, and evaluate the applicability of using barcoding for the identification of fish species. Barcode sequences were obtained from seven orders, 17 families, 23 genera and 26 species, which were validated through phylogenetic analysis, morphological measurements, and literature review. Our results showed that 43% of fish species in this region are endemic, confirmed the presence of known species in the area, and included the addition of three new records of native (Hoplias microlepis, Rhamdia guatemalensis and Sicydium salvini) and an introduced species (Xiphophorus maculatus) to Ecuador. In addition, eight species were barcoded for the first time. Species identification based on barcoding and morphology showed discrepancy with species lists from previous studies in the CGE, suggesting that the current baseline of western fishes of Ecuador is still incomplete. Because this study analyzed fishes from a relatively small basin (165 km2), more molecular-based studies focusing on fish are needed to achieve a robust sequence reference library of species inhabiting Western Ecuador. The new sequences of this study will be useful for future comparisons and biodiversity monitoring, supporting the application of barcoding tools for studying fish diversity in genetically unexplored regions and to develop well-informed conservation programs.
The genus
includes 146 species of cryptozoic snakes occurring from Panama to northeastern Argentina. Here, a molecular phylogeny of this genus is presented, which encompasses 29% (= 42; six are ...included here for the first time) of the species currently recognized. Morphological and phylogenetic support is found for three new species of ground snakes, which are described here based on their unique combination of molecular, meristic, and color pattern characteristics. The name
Prado, 1939 is revalidated for a Colombian snake species previously subsumed under
Boulenger, 1894 based on new material collected in Ecuador. Reidentifications are provided for
voucher specimens and sequences deposited in GenBank. With these changes, the number of
reported in Ecuador increases from 27 to 31 species. Finally, attention is given to the importance of using a biogeographical framework that includes molecular data and a comprehensive geographic sampling when proposing species limits in complex taxonomic groups.
The explosive diversity of rainfrogs (
Pristimantis
spp) reaches its highest levels in the mountains of the Tropical Andes, with remarkable cryptic species mainly in unexplored areas of Ecuador. ...Based on phylogenetics, morphometric traits, skull osteology and bioacoustics, we describe two new species of
Pristimantis
, previously confused with
Pristimantis gladiator
, that belong to the subgenus Trachyphrynus traditionally known as the
Pristimantis myersi
species group. The two new taxa are closely related, but have allopatric distributions. We discuss the importance of the Quijos and Pastaza River valleys in the diversification along Amazonian slopes of the Ecuadorian Andes.
The Tropical Andes is the world's most biodiverse hotspot. This region contains >1,000 amphibian species, more than half of which are endemic. Herein we describe two new glassfrog species ...(Centrolenidae:
) that we discovered within relatively unexplored and isolated localities of the Ecuadorian Andes.
We employed morphological, acoustic, and molecular methods to test the hypothesis that
sp. nov and
sp. nov. are species new to science. Following standard methods, we generated mitochondrial sequences (16S) of 37 individuals in the genus
. We inferred the phylogenetic relationships of the two new species in comparison to all other glassfrogs using Maximum Likelihood. In addition to describing the call of
sp. nov., we performed a discriminant analysis of principal components (DAPC) with the advertisement call characteristics of several congeners.
Based on an integrative taxonomy approach, we describe two new species. Morphological traits and the inferred phylogeny unambiguously place the new taxa in the genus
. Both species are distinguished from other glassfrogs mainly by their dorsal coloration (
., dorsum lime green with small light yellow spots, head usually with interorbital bar) and transparent pericardium (
., the heart is visible through the ventral skin). The new species exhibit a high morphological similarity (
., cryptic) and occur within relatively close geographical proximity (closest aerial distance = 18.9 km); however, their uncorrected
distance for the mitochondrial gene 16S is 4.6-4.7%, a value that greatly exceeds the genetic distance between closely related species of centrolenid frogs. The DAPC revealed that the advertisement call of
sp. nov. is acoustically distinct.
Our findings are congruent with several previous studies that report a high degree of endemism in the Toisán mountain range, which appears to be isolated from the main Andean cordillera for some amphibian groups. We recommend that both
sp. nov. and
sp. nov. be listed as Endangered, following IUCN criteria. These new species provide another example of cryptic diversity in the Andes-further evidence that the region fosters much more biodiversity than we have the resources to catalog. Threatened by mining and other exploitative industries, these glassfrogs and many other yet-to-be-discovered Andean species highlight the dire need for effective conservation measures-especially in northwestern Ecuador.
We have discovered a spectacular new species of frog in the genus
, belonging to the
species group. The adult female is characterized by a mostly black body with large bright red spots on the dorsal ...and ventral surface, extremities, and toe pads. The adult male is unknown. Small juveniles are characterized by a yellow body with variable black markings on the flanks; while one larger juvenile displayed irregular orange or yellow marks on a black background color, with light orange or yellow toe pads. Additional distinctive external morphological features such as cloacal ornamentation are described, and some osteological details are imaged and analyzed. The performed phylogeny places the new species as the sister to a clade consisting of ten taxa, all of which are part of the
group. We use genetic distances to fit the new species into a published time-calibrated phylogeny of this group; our analysis based on the published chronology suggests that the divergence of the new species from its known congeners pre-dates the Quaternary period. The new species is currently only known only from Cerro Mayordomo, in Fundación EcoMinga´s Machay Reserve, at 2,900 m in the eastern Andes of Tungurahua province, Ecuador, near the southern edge of Los Llanganates National Park, but its real distribution may be larger.
A fundamental gap in climate change vulnerability research is an understanding of the relative thermal sensitivity of ectotherms. Aquatic insects are vital to stream ecosystem function and ...biodiversity but insufficiently studied with respect to their thermal physiology. With global temperatures rising at an unprecedented rate, it is imperative that we know how aquatic insects respond to increasing temperature and whether these responses vary among taxa, latitudes, and elevations. We evaluated the thermal sensitivity of standard metabolic rate in stream‐dwelling baetid mayflies and perlid stoneflies across a ~2,000 m elevation gradient in the temperate Rocky Mountains in Colorado, USA, and the tropical Andes in Napo, Ecuador. We used temperature‐controlled water baths and microrespirometry to estimate changes in oxygen consumption. Tropical mayflies generally exhibited greater thermal sensitivity in metabolism compared to temperate mayflies; tropical mayfly metabolic rates increased more rapidly with temperature and the insects more frequently exhibited behavioral signs of thermal stress. By contrast, temperate and tropical stoneflies did not clearly differ. Varied responses to temperature among baetid mayflies and perlid stoneflies may reflect differences in evolutionary history or ecological roles as herbivores and predators, respectively. Our results show that there is physiological variation across elevations and species and that low‐elevation tropical mayflies may be especially imperiled by climate warming. Given such variation among species, broad generalizations about the vulnerability of tropical ectotherms should be made more cautiously.
Schematic of expectations for change in standard metabolic rate (SMR; O2 consumption) and performance in response to temperature in an aquatic ectotherm. The thermal performance curve (TPC; green line) is a functional performance trait where higher performance is better. TOPT, where performance is highest, reflects the animal's preferred temperature. The oxygen consumption curve (dashed line) is a special case of TPC. T‐MRPEAK represents the temperature at which SMR is so high that it equals maximum metabolic rate. Predictions for variation in metabolic rate, based on the Climate Variability Hypothesis, are shown on the right. Our predictions were met in mayflies, but not stoneflies.
Widespread introduced species can be leveraged to investigate the genetic, ecological and adaptive processes underlying rapid evolution and range expansion, particularly the contributions of genetic ...diversity to adaptation. Rhinella marina, the cane toad, has been a focus of invasion biology for decades in Australia. However, their introduction history in North America is less clear. Here, we investigated the roles of introduction history and genetic diversity in establishment success of cane toads across their introduced range. We used reduced representation sequencing (ddRAD) to obtain 34,000 SNPs from 247 toads in native (French Guiana, Guyana, Ecuador, Panama, Texas) and introduced (Bermuda, southern Florida, northern Florida, Hawaiʻi, Puerto Rico) populations. Unlike all other cane toad introductions, we found that Florida populations were more closely related to native Central American lineages (R. horribilis), than to native Southern American lineages (R. marina). Furthermore, we found high levels of diversity and population structure in the native range, corroborating suggestions that R. marina is a species complex. We also found that introduced populations exhibit only slightly lower genetic diversity than native populations. Together with demographic analyses, this indicates founding populations of toads in Florida were larger than previously reported. Lastly, within R. marina, only one of 245 putatively adaptive SNPs showed fixed differences between native and introduced ranges, suggesting that putative selection in these introduced populations is based upon existing genetic variation. Our findings highlight the importance of genetic sequencing in understanding biological introductions and hint at the role of standing genetic variation in range expansion.
is the most diverse genus of terrestrial frogs. Historically, it has been divided into several phenetic groups in order to facilitate species identification. However, in light of phylogenetic ...analysis, many of these groups have been shown to be non-monophyletic, denoting a high degree of morphological convergence and limited number of diagnostic traits. In this study, we focus on the
group, an assemblage of small rainfrogs distributed throughout the Andes of Ecuador and Colombia, whose external morphology is highly conserved, and its species diversity and evolutionary relationships largely unknown.
We inferred a new phylogenetic hypothesis for the frog genus
, including all available sequences of the mtDNA 16S rRNA, as well as new DNA sequences from 175 specimens. Our sampling included 19 of the 24 species currently recognized as part of the
group.
Our new evolutionary hypothesis recovered the
group as non-monophyletic and composed of 16 species. Therefore, we exclude
and
in order to preserve the monophyly of the group. We discovered at least eight candidate species, most of them hidden under the names of
, and
.
Our results reveal the occurrence of a high level of cryptic diversity to the species level within the
group and highlight the need to redefine some of its species and reassess their conservation status. We suggest that the conservation status of six species within the group need to be re-evaluated because they exhibit smaller distributions than previously thought; these species are:
, and
. Finally, given that the
group, as defined in this work, is monophyletic and morphologically diagnosable, and that
is an available name for the clade containing
, we implement
as a formal subgenus name for the
group.
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