Genetic variability in three species of Gymnotus Linnaeus, 1758 (Gymnotiformes: Gymnotidae) from Caracu stream of the upper Paraná River basin, Brazil

Rezende, Judy Ruiz; Renesto, Erasmo; Zawadzki, Cláudio Henrique

doi:10.1590/s1679-62252009000400010

Cited by 5 publications

(32 citation statements)

References 34 publications

(32 reference statements)

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“…The representatives of the Gymnotiformes order have specific characteristics, such as the capacity to emit electrical pulses used in communication, foraging, navigation and orientation in relation to the substrate (CRAMPTON and ALBERT, 2006). These characteristics facilitate the establishment of the species in environments with high turbidity and the presence of aquatic vegetation (REZENDE et al, 2009), as observed at the sites sampled in this study. The Azul River microbasin, which is widely exploited by agriculture and livestock activities, is characterized by a reduced area of riparian vegetation, causing high turbidity of the water and the development of dense marginal aquatic vegetation, which enables the successful colonization by the representatives of the Gymnotiformes order.…”

Section: Discussionsupporting

confidence: 53%

Ocorrência de espécies de peixes não nativos em um rio Neotropical sob a influência da atividade aquícola

Ribeiro

2018

Bol. Inst. Pesca

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The introduction of non-native species is one of the greatest global changes and is a substantial threat to continental fish fauna. This study aimed to evaluate the composition and structure of the fish assemblage of the Azul River, a tributary along the left margin of the Piquiri River basin, to determine the occurrence, abundance and spatial distribution of non-native fish species. Sampling was carried out from February to November 2014 at three sites along the river using of electric fishing equipment. Thirty-two fish species belonging to 20 genera, 11 families and five orders were collected. Eight non-native fish species were recorded, and Gymnotus inaequilabiatus and Oreochromis niloticus were listed among the five most abundant species in the Azul River. The fish fauna followed a distribution pattern expected for the Neotropical region, with a predominance of Characiformes and Siluriformes. However, the high representativeness of the abundance of the non-native species of the Gymnotiformes and Perciformes orders highlights the potential negative impacts on the structure of the fish assemblages of the Azul River due to species introductions.

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“…61 Previous studies of several Neotropical fish species have reached similar conclusions, with a mean genetic divergence among congeners of *5%, 60 and exclusive alleles being found in many cases, confirming the low genetic variability found in these species. 62 Similar values were recorded in the basin of the Itapecuru River, 63 in northeastern Brazil, which permitted the reliable identification of 92.19% of the fish species, with interspecific differences of <3% in most cases, demonstrating considerable potential for the discrimination of cryptic species. In the present study, the variation found among congeners was much FIG.…”

Section: Discussionsupporting

confidence: 63%

Gymnotus paraguensis, a Good Example of Phenotypic Plasticity in the Pantanal Biome, Brazil

et al. 2021

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Gymnotus is the most studied genus of the order Gymnotiformes, but the morphological similarities of the different species make it difficult to identify taxa reliably. The present study is a continuation of the ongoing research into the taxonomic diversity of the stocks of Gymnotus sold as live bait in the Pantanal, Brazil. These studies have been based on cytogenetic analyses, DNA barcoding, and the analysis of coloration patterns. The results of the cytogenetic analysis confirmed the presence of three distinct strains, recognized as Gymnotus paraguensis, G. sylvius, and G. pantanal. However, the results revealed that the molecular operational taxonomic units identified as G. paraguensis actually include a relatively diverse set of fish, separated by considerable genetic distances. As the G. paraguensis specimens also presented considerable variation in coloration patterns, further genetic diversity analyses were conducted on these individuals, to test the hypothesis that more than one species is present in this cytotaxonomic unit. The haplotype network revealed a regional pattern in the distribution of this species. The results indicate that the observed variation in coloration patterns is associated with a high degree of phenotypic plasticity in G. paraguensis. These findings emphasize the importance of using an integrative approach for a more accurate diagnosis of Gymnotus, in particular, the species marketed as live bait for the fisheries of the upper Paraguay River basin in the Brazilian Pantanal.

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“…Among the species found in Paraná River and Coastal Rivers basins, cytogenetic reports are available for Gymnotus carapo (LINNAEUS 1758) (2n = 54), Gymnotus inaequilabiatus (VALENCIENNES 1839) (2n = 52), Gymnotus sylvius (ALBERT and FERN-ANDES-MATOLI 1999) (2n = 40) and Gymnotus pantherinus (STEINDACHNER 1908) (2n = 52) (FERNANDES-MATIOLI et al 2001). Such variation in the chromosomal number from 2n = 40 to 2n = 54, coupled with the fact that speciation events leading to the origin of some Gymnotus species are considered to be recent (REZENDE et al 2009), make the genus an excellent material to study the occurrence of chromosomal rearrangements in the evolutionary history of this fi sh group.…”

Section: Introductionmentioning

confidence: 99%

Evidence of chromosome fusion in Gymnotus sylvius Albert & Fernandes-Matoli, 1999 (Teleostei: Gymnotiformes) detected by telomeric probes and R-banding

Felippe

Foresti

2010

Caryologia

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Gymnotus cf. carapo and Gymnotus sylvius are two fi sh species inhabiting the Upper Parana River Basin, presenting respectively 2n = 54 and 2n = 40 chromosomes. In the present cytogenetic analysis, R-banding and telomere-sequence hybridization were carried out in order to determine the possible relationship between the karyotipes of these two species. Incorporation bands (R-bands) obtained for the two species allowed the identifi cation of chromosome similarities, showing to be an usefull alternative to the G-banding methods, which fail in producing satisfying results in most of analyzed fi sh species. This approach, associated with the hybridization of telomeric sequences, permited to identify chromosomal rearrangements that could be used as indicators of karyotypic evolution within the group. In the present case, telomeric sequences were detected in the centromeric region of two metacentric chromosome pairs of Gymnotus sylvius. The results obtained after hybridization with the telomere sequences, coupled with the chromosome homeologies detected by R-banding, showed that G. cf. carapo and G. sylvius should present a common ancestor, and this may also be corroborated by the similarities found in three chromosome pairs, that seem to have been conserved during the evolution of the two species. Based on the data here presented we propose that G. sylvius may have undergone a recent process of chromosome fusion that resulted in the diminution of its chromosome number.

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Genetic variability in three species of Gymnotus Linnaeus, 1758 (Gymnotiformes: Gymnotidae) from Caracu stream of the upper Paraná River basin, Brazil

Cited by 5 publications

References 34 publications

Ocorrência de espécies de peixes não nativos em um rio Neotropical sob a influência da atividade aquícola

Gymnotus paraguensis, a Good Example of Phenotypic Plasticity in the Pantanal Biome, Brazil

Evidence of chromosome fusion in Gymnotus sylvius Albert & Fernandes-Matoli, 1999 (Teleostei: Gymnotiformes) detected by telomeric probes and R-banding

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Genetic variability in three species of Gymnotus Linnaeus, 1758 (Gymnotiformes: Gymnotidae) from Caracu stream of the upper Paraná River basin, Brazil

Cited by 5 publications

References 34 publications

Ocorrência de espécies de peixes não nativos em um rio Neotropical sob a influência da atividade aquí­­cola

Gymnotus paraguensis, a Good Example of Phenotypic Plasticity in the Pantanal Biome, Brazil

Evidence of chromosome fusion in Gymnotus sylvius Albert & Fernandes-Matoli, 1999 (Teleostei: Gymnotiformes) detected by telomeric probes and R-banding

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Ocorrência de espécies de peixes não nativos em um rio Neotropical sob a influência da atividade aquícola