An exploratory survey of fish species inhabiting rapids from the Tocantins-Araguaia River Basin: perspectives on species diversity and conservation

Biota Neotropica, Journal Year: 2025, Volume and Issue: 25(1)

Published: Jan. 1, 2025

Abstract Rapid habitats are characterized by an environment of intense hydrologic dynamic, hosting freshwater biodiversity that has adapted to these conditions. Knowledge the diversity rapids-dwelling fish is still unsatisfactory in South America’s rivers. Our study surveyed species within rapids from Tocantins-Araguaia River Basin (TARB). We assessed 27 stretches different localities along TARB, using various fishing gears with free diving, preferably deeper areas rocky stretches. survey yield 1668 specimens, 107 species, 79 genera, 28 families, and 10 orders. Among these, 11 categorized as being under some threat, according IUCN ICMbio. The Rhynchodoras xingui Mylesinus paucisquamatus, both listed threatened at ICMbio, were not recorded during our expeditions area. Baryancistrus longipinnis was only Pedral do Lourenço, suggesting a possible distribution retraction. This first surveying focused exclusively on ichthyofauna associated Despite significant alterations past four decades, particularly due construction hydroelectric power plants, house rich biodiversity. results indicate remnants bedrock TARB provide suitable niches for ichthyofauna, highlighting their importance potential conservation units.

Language: Английский

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Ecotoxicological impact of the fungicide tebuconazole on fish: a historical review, global trends and challenges

Aquatic Toxicology, Journal Year: 2025, Volume and Issue: unknown, P. 107398 - 107398

Published: May 1, 2025

Language: Английский

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Freshwater fish diversity in the western Amazon basin shaped by Andean uplift since the Late Cretaceous

Nature Ecology & Evolution, Journal Year: 2023, Volume and Issue: 7(12), P. 2037 - 2044

Published: Oct. 19, 2023

South America is home to the highest freshwater fish biodiversity on Earth, and hotspot of species richness located in western Amazon basin. The location this enigmatic, as it inconsistent with pattern observed river systems across world increasing towards a river's mouth. Here we investigate role capture events caused by Andean mountain building repeated episodes flooding Amazonia shaping modern-day fishes America, particular. To end, combine reconstruction networks since 80 Ma mechanistic model simulating dispersal, allopatric speciation extinction over dynamic landscape rivers lakes. We show that consequent numerous small habitats be highly dynamic, leading high diversification rates exceptional richness. history marine incursions lakes, including Miocene Pebas mega-wetland system Amazonia, played secondary role.

Language: Английский

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A variant W chromosome in Centromochlus heckelii (Siluriformes, Auchenipteridae) and the role of repeated DNA in its heteromorphism

Genetics and Molecular Biology, Journal Year: 2025, Volume and Issue: 48(1)

Published: Jan. 1, 2025

Abstract Centromochlus heckelii has the lowest diploid chromosome number (2n = 46) and only described heteromorphic sex system in Auchenipteridae. This study presents a population of C. from Central Amazon basin with subtle variations karyotype composition variant W distinct morphology increased C-positive heterochromatin content. In this population, is subtelocentric, whereas previous on reported metacentric chromosome. Constitutive (CH) accumulation microsatellite motifs have significantly contributed to enlargement. Notably, exhibits numerous interstitial telomeric sites (ITSs). Some these ITSs might represent genuine chromosomal fusion points due reduced 2n; however, additional mechanisms, such as inversions, translocations, transpositions, or association satellite DNA, are likely responsible for unusual pattern. The 18S rDNA were found both Z chromosomes all individuals. However, two individuals exhibited an site single homologous pair 20, characterizing intrapopulation polymorphism. 5S pairs, distinguishing other Centromochlinae species further supporting it one most efficient cytotaxonomic markers within subfamily.

Language: Английский

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Hydrological Connectivity Enhances Fish Biodiversity in Amazonian Mining Ponds: Insights from eDNA and Traditional Sampling

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 29, 2025

Abstract The expansion of artisanal and small-scale gold mining (ASGM) in the Madre de Dios region Peruvian Amazon has transformed primary forests into a novel wetland complex thousands abandoned ponds. Despite their ecological relevance, post-mining recovery these systems remains understudied, particularly regarding fish biodiversity recolonization. In this study, we evaluate community richness composition ponds different dimensions, years post abandonment, degree pulse flood connectivity using traditional collection-based methods environmental DNA (eDNA) with 12S COI markers. We compared two inventory contrasted results from ASGM waterbodies those obtained nearby pristine oxbow lakes. Overall, registered more at all sites eDNA vs methods, especially marker. identified 14 13 unique genera eDNA, respectively, 40 detected by both approaches, evidencing complementarity. Notably, found that flooding was main predictor species among (p-value < 0.05). 11 to 22, 23 71, 56 morphospecies non-flooded ponds, flooded lakes, respectively. Furthermore, most influenced were similar Our findings highlight role hydrological within mining-impacted wetlands. Future restoration efforts should enhance aquatic accelerate environments.

Language: Английский

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Small Fishes, Big Issues: Species Delimitation in Hemigrammus Marginatus, Gill, 1958 (Acestrorhamphidae: Pristellinae) from Brazilian Coastal Basins Based on Integrative Genetics

Zebrafish, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 14, 2025

The small characins represent a systematic puzzle in the Neotropical ichthyofauna as result of independent miniaturization processes, adaptive convergence and lack diagnostic characters for several genera. In order to diminish taxonomic uncertainties evolutionary pathways Hemigrammus, we carried out an integrative genetic analysis putatively widespread Hemigrammus marginatus Ellis, 1958 by combining cytogenetic molecular data based on mitochondrial Cytochrome C Oxidase subunit I (COI). Specimens H. from type locality Itapicuru River basin other two populations coastal rivers northeastern Brazil were analyzed compared with available regions South America. Conspicuous macro microkaryotypic differences detected between samples southern (Upper Paraná basin). Likewise, DNA barcoding species delimitation analyses recovered distinct Molecular Operational Taxonomical Units within marginatus. Therefore, population should be referred stricto sensu, representing restricted characin taxon drainages (including São Francisco basin) along Brazil, while this fish need taxonomically revised managed unique lineages.

Language: Английский

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Widespread and strong impacts of river fragmentation by human barriers on fishes in the Mekong River Basin

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: March 5, 2025

The Mekong River, a global freshwater biodiversity hotspot, has suffered from intensive barrier construction, resulting in major challenges safeguarding its fauna. Here, we provide comprehensive evaluation of the impacts river barriers on distribution 1,032 fish species Basin. Our analysis revealed that 93% suffer habitat fragmentation, and with larger range requirements experienced higher fragmentation impacts. Sub-basins along main channel Lower had high values richness but relatively Across all migration types, potamodromous worst status (Fragmentation Index, 42.56 [95% CI, 36.95–46.05]), followed by catadromous fish. Among IUCN conservation categories, Critically Endangered highest index (33.34 [12.53–46.40]). small dams sluice gates contribute more to than large dams.

Language: Английский

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Biogeography of Vertebrates

Elsevier eBooks, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Language: Английский

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The latitudinal speciation gradient in freshwater fishes: higher speciation at higher latitudes in the northern hemisphere

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: March 13, 2025

Speciation rates are a key driver of diversity patterns and often used to explain the latitudinal gradient (LDG). However, variation in speciation at both assemblage species levels remains poorly explored freshwater fishes. This highlights gap understanding mechanisms driving geographic biodiversity gradients Here, we investigated fishes, using comprehensive database fish distributions phylogenetic relationships Actinopterygian We estimated three metrics (BAMM, DR, ClaDS) evaluated through spatial regressions levels. Finally, analyzed those based on assemblage's structure. Our results show that areas with highest were located tropics. general pattern revealed positive relationship between absolute latitude rates. is generally absent tropical regions below 23.8° became significant only higher latitudes, particularly Northern Hemisphere. do not find level, mainly due strong influence hyper-diverse groups like Cichliformes. When Cichliformes excluded, significant, aligning assemblage-level results. The whit also match recent radiation clustering all latitudes. septentrional assemblages high rates, which reflects environmental filtering dispersal events consistent glaciation deglaciation Pleistocene.

Language: Английский

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Assembling the Pecos River fish fauna: barrier displacement on the Southern Great Plains, North America

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 20, 2025

Barrier displacement by river capture is an important mechanism for the assembly of freshwater fish faunas. The production increasingly comprehensive and rigorously dated phylogentic trees major clades fishes, along with improved resolution in historical geomorphology, provide unprecedented opportunity to develop thorough biogeographical scenarios faunal that synthesise existing knowledge detailed context future study. Pecos River southwestern North America a textbook example drainage formation provides straightforward case capture. Fishes ultimately confined middle section (Capitan area endemism) have their closest relatives Brazos, Colorado (Texas), Red rivers, which served as ancient dispersal corridors from Mississippi drainage. Capitan endemism developed association two dissolution basins that, Late Miocene, captured headwaters these rivers. In Pliocene or Early Pleistocene, endorheic was overflowed into tributary Río Grande, became lower River. nascent also harboured endemic-fish assemblage part nexus springfed rivers (ancestral Devils River, River) comprised endemism. Even after through-flowing linked areas endemism, many endemic species remained only within original giving composite fauna. Grande connection later allowed fishes dispersing Gulf Mexico coast, aided Pleistocene sea-level falls glacial outbursts, not populate but disperse up Incision valley uplift Sangre de Cristo Mountains empowered headwater streams adjacent South Canadian bringing additional fishes. More recently, humans introduced at least 50 drainage, while human impacts fragmented native Non-native versus status remains uncertain several (e.g. Miniellus stramineus) multiple lineages diverse origin may exist some widespread, polytypic like Cyprinella lutrensis Pimephales promelas. fauna anomaly explainable complex geomorphological history produced it. As such, it unique studies fish-assemblage evolutionary ecology. Also, its neighbouring drainages helps clarify biogeography (as here). Further broadening this synthesis could support large spatial scales, illustrating potential now exists reconstructing regional river-drainage

Language: Английский

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