Dataset Information

Checklist of the ichthyofauna of the Rio Negro basin in the Brazilian Amazon.

ABSTRACT: This study presents an extensive review of published and unpublished occurrence records of fish species in the Rio Negro drainage system within the Brazilian territory. The data was gathered from two main sources: 1) litterature compilations of species occurrence records, including original descriptions and revisionary studies; and 2) specimens verification at the INPA fish collection. The results reveal a rich and diversified ichthyofauna, with 1,165 species distributed in 17 orders (+ two incertae sedis), 56 families, and 389 genera. A large portion of the fish fauna (54.3% of the species) is composed of small-sized fishes < 10 cm in standard length. The main groups are Characiformes (454 species; 39.0%), Siluriformes (416; 35.7%), Gymnotiformes (105; 9.0%), and Cichliformes (102; 8.8%). The species composition differs between the main aquatic environments, such as: main channel (159 species), lakes (296), tributary rivers (596), small streams (234), seasonal beaches (186), and rapids (41). Part of the ichthyofauna is shared with adjacent basins, such as the Orinoco, rivers of the Guiana Shield, lower Solimões/Amazonas and upper Amazonas, which contributes to the remarkable ichthyofaunal diversity of the basin. A high rate of species endemism was observed in Characidae (24), Loricariidae (18), Cichlidae (18) and Callichthyidae (18), totalling 156 species (13.4%) endemic to the basin. An estimation of the species richness for the Rio Negro basin, considering 23 published references, resulted in 1,466 and 1,759 species (Jackknife 1 and 2, respectively), which seems reasonable when considering the large number of morphotypes left out of the present list and the low sampling effort in many areas of the basin. The results presented herein provide an additional tool for environmental managers and decision makers for conservation purposes of one of the richest and most well-preserved sub-basins of the Rio Amazonas system.

SUBMITTER: Beltrao H

PROVIDER: S-EPMC6813176 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Checklist of the ichthyofauna of the Rio Negro basin in the Brazilian Amazon.

Beltrão Hélio H Zuanon Jansen J Ferreira Efrem E

ZooKeys 20191017

This study presents an extensive review of published and unpublished occurrence records of fish species in the Rio Negro drainage system within the Brazilian territory. The data was gathered from two main sources: 1) litterature compilations of species occurrence records, including original descriptions and revisionary studies; and 2) specimens verification at the INPA fish collection. The results reveal a rich and diversified ichthyofauna, with 1,165 species distributed in 17 orders (+ two ince ...[more]

PMID: 31662611

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Project description:BACKGROUND:Plasmodium vivax is the most widespread human malaria parasite outside Africa and is the predominant parasite in the Americas. Increasing reports of P. vivax disease severity, together with the emergence of drug-resistant strains, underscore the urgency of the development of vaccines against P. vivax. Polymorphisms on DBP-II-gene could act as an immune evasion mechanism and, consequently, limited the vaccine efficacy. This study aimed to investigate the pvdbp-II genetic diversity in two Brazilian regions with different epidemiological patterns: the unstable transmission area in the Atlantic Forest (AF) of Rio de Janeiro and; the fixed malaria-endemic area in Brazilian Amazon (BA). METHODS:216 Brazilian P. vivax infected blood samples, diagnosed by microscopic examination and PCR, were investigated. The region flanking pvdbp-II was amplified by PCR and sequenced. Genetic polymorphisms of pvdbp-II were estimated based on the number of segregating sites and nucleotide and haplotype diversities; the degree of differentiation between-regions was evaluated applying Wright's statistics. Natural selection was calculated using the rate of nonsynonymous per synonymous substitutions with the Z-test, and the evolutionary distance was estimated based on the reconstructed tree. RESULTS:79 samples from AF and 137 from BA were successfully sequenced. The analyses showed 28 polymorphic sites distributed in 21 codons, with only 5% of the samples Salvador 1 type. The highest rates of polymorphic sites were found in B- and T cell epitopes. Unexpectedly, the nucleotide diversity in pvdbp-II was higher in AF (0.01) than in BA (0.008). Among the 28 SNPs detected, 18 are shared between P. vivax isolates from AF and BA regions, but 8 SNPs were exclusively detected in AF-I322S, K371N, E385Q, E385T, K386T, K411N, I419L and I419R-and 2 (N375D and I419M) arose exclusively in BA. These findings could suggest the potential of these geographical clusters as population-specific-signatures that may be useful to track the origin of infections. The sample size should be increased in order to confirm this possibility. CONCLUSIONS:The results highlight that the pvdbp-II polymorphisms are positively selected by host's immune pressure. The characterization of pvdbp-II polymorphisms might be useful for designing effective DBP-II-based vaccines.

Project description:The Neotropics contain one of the most diverse assemblages of freshwater fishes worldwide. Part of this diversity is shared between the Orinoco and Amazon basins. These basins have been separated for a long time due to the Vaupes Arch, rising between 10-11 Ma. Today, there is only one permanent connection between the Orinoco and Negro (Amazon) basins, known as the Casiquiare Canal. However, alternative corridors allowing fish dispersion between both basins have been proposed. The cardinal tetra (Paracheirodon axelrodi), the most important fish in the ornamental world market, is distributed in both basins. Here we investigated P. axelrodi phylogeography, population structure, and potential routes of migration and connectivity between the two basins. A total of 468 bp of the mitochondrial gene (COI), 555 bp of the nuclear gene fragment (MYH6), and eight microsatellite loci were analyzed. As a result, we found two major genetic clusters as the most likely scenario (K = 2), but they were not discreetly distributed between basins. A gradient of genetic admixture was observed in Cucui and São Gabriel da Cachoeira, between the upper Negro River and the upper Orinoco. Samples from the middle-lower Negro River were highly structured. Cucui (Negro basin) was more similar to the Orinoco than to the rest of the Negro basin populations. However, substructure was also observed by the discriminant analysis, fixation indices and other hierarchichal structure analyses (K = 3 - 6), showing three major geographic clusters: Orinoco, Cucui, and the remaining Negro basin. Unidirectional migration patterns were detected between basins: via Cucui toward Orinoco and via the remaining of the Negro basin toward Orinoco. Results from the Relaxed Random Walk analysis support a very recent origin of this species in the headwater Orinoco basin (Western Guiana Shield, at late Pleistocene) with a later rapid colonization of the remaining Orinoco basin and almost simultaneously the Negro River via Cucui, between 0.115 until about 0.001 Ma. Historical biogeography and population genetic patterns observed here for Cardinal tetra, seem to be better explained by river capture, physical, or ecological barriers than due to the geographic distance.

Dataset Information

Checklist of the ichthyofauna of the Rio Negro basin in the Brazilian Amazon.

Publications

Checklist of the ichthyofauna of the Rio Negro basin in the Brazilian Amazon.

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