Two New Species of Gymnotus (Gymnotiformes: Gymnotidae) from Brazil and Historical Biogeography of the Subgenus Lamontianus

Kim, Lesley Y.; Crampton, William G. R.; Albert, James S.

doi:10.1643/ci-19-205

Cited by 3 publications

(4 citation statements)

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“…The study of behavior in closely related species has been useful to understand the mechanisms underlying the evolution of social behavior (Goymann & Schwabl, 2021). The genus Gymnotus , with 46 species of electric fish described to date (Albert, 2001; Craig et al., 2018; Kim et al., 2020), emerges as an excellent model to study the evolutionary history and neural mechanisms of the agonistic behavior, which appears as a remarkable feature of this genus, as described for Gymnotus carapo and Gymnotus omarorum (Batista et al., 2012; Black‐Cleworth, 1970; Perrone & Silva, 2018; Zubizarreta et al., 2020). This study contributes the first description of the agonistic behavior of Gymnotus sylvius highlighting its similarities with the behavior of other species of the same genus as well as its distinctive aspects.…”

Section: Discussionmentioning

confidence: 99%

“…At present, this genus includes 46 species (Craig et al, 2018;Kim et al, 2020) that occur in most freshwater habitats of the lowland Neotropics (Richer-de-Forges et al, 2009). Only four species of Gymnotus occur in the southernmost freshwater environments of Argentina.…”

Section: Introductionmentioning

confidence: 99%

“…The genus Gymnotus has a broad distribution range from southern Mexico to the Salado River Basin in Argentina (Albert, 2001). At present, this genus includes 46 species (Craig et al., 2018; Kim et al., 2020) that occur in most freshwater habitats of the lowland Neotropics (Richer‐de‐Forges et al., 2009). Only four species of Gymnotus occur in the southernmost freshwater environments of Argentina.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the agonistic behavior of the weakly electric fish Gymnotus sylvius

Perrone,

Hurtado,

Silva

et al. 2024

Ethology

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Electric fish are good models in neuroethology as any behavior in electric fish involves both locomotor and electrical displays, which are experimentally accessible and controlled by well‐known neural circuits. The agonistic behavior within the genus Gymnotus has been evaluated in Gymnotus carapo and Gymnotus omarorum, providing an advantageous model system to address comparative analyses. Gymnotus sylvius is a weakly electric fish which occurs in sympatry with G. omarorum in freshwater environments of Argentina. Here, we describe the agonistic behavior of G. sylvius in laboratory conditions. All dyads engaged in intense fights, with a latency to the first attack of 8 ± 7.8 s and a contest phase of 42.71 ± 31.7 s. Individual initiative in the first attack predicted contest outcome with no apparent influence of body weight asymmetry between contenders. Contenders did not escalate in their aggression during the short contest; in turn, subordinates tended to retreat in response to dominants' attacks. Submission and dominance were expressed by electric signals: dominants increased their basal electric organ discharge (EOD) rate after contest resolution, resulting in a persistent EOD rate rank. Subordinates also emitted chirps and offs during the contest and post‐resolution phases without a clear temporal pattern. The agonistic behavior of G. sylvius presents some similarities with other species of the genus Gymnotus: EOD rank between dominants and subordinates, electric signals of submission, and the presence of attacks in the post‐resolution phase. On the other hand, it also presents differences: a shorter evaluation phase in G. sylvius, initiative as a determinant of outcome, a higher attack rate of dominants in G. sylvius, a different temporal pattern of chirps, and different mechanisms to separate EOD rate of dominants and subordinates. These facts open a promising road to analyze the evolution of different neuroendocrine strategies, operating on homologous neural pathways, to command the same behavior.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization of the agonistic behavior of the weakly electric fish Gymnotus sylvius

Perrone,

Hurtado,

Silva

et al. 2024

Ethology

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“…The genus Gymnotus (Gymnotiformes, Teleostei) is a large monophyletic group of weakly-electric freshwater fish. It is the most speciose genus of the order, with 46 validated species (Craig et al, 2019;Kim et al, 2020;Fricke et al, 2021), widely distributed in the Neotropical region (Central and South America). The highest diversity is found in the Amazon-Orinoco-Guiana basins (Mago-Leccia, 1994;Albert, 2001;Albert and Crampton, 2005).…”

Section: Introductionmentioning

confidence: 99%

Chromosome Painting in Gymnotus carapo “Catalão” (Gymnotiformes, Teleostei): Dynamics of Chromosomal Rearrangements in Cryptic Species

et al. 2022

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The genus Gymnotus is a large monophyletic group of freshwater weakly-electric fishes, with wide distribution in Central and South America. It has 46 valid species divided into six subgenera (Gymnotus, Tijax, Tigre, Lamontianus, Tigrinus and Pantherus) with large chromosome plasticity and diploid numbers (2n) ranging from 34 to 54. Within this rich diversity, there is controversy about whether Gymnotus (Gymnotus) carapo species is a single widespread species or a complex of cryptic species. Cytogenetic studies show different diploid numbers for G. carapo species, ranging from 40 to 54 chromosomes with varied karyotypes found even between populations sharing the same 2n. Whole chromosome painting has been used in studies on fish species and recently has been used for tracking the chromosomal evolution of Gymnotus and assisting in its cytotaxonomy. Comparative genomic mapping using chromosome painting has shown more complex rearrangements in Gymnotus carapo than shown in previous studies by classical cytogenetics. These studies demonstrate that multiple chromosome pairs are involved in its chromosomal reorganization, suggesting the presence of a complex of cryptic species due to a post zygotic barrier. In the present study, metaphase chromosomes of G. carapo occidentalis “catalão” (GCC, 2n = 40, 30m/sm+10st/a) from the Catalão Lake, Amazonas, Brazil, were hybridized with whole chromosome probes derived from the chromosomes of G. carapo (GCA, 2n = 42, 30m/sm+12st/a). The results reveal chromosome rearrangements and a high number of repetitive DNA sites. Of the 12 pairs of G. carapo chromosomes that could be individually identified (GCA 1–3, 6, 7, 9, 14, 16 and 18–21), 8 pairs (GCA 1, 2, 6, 7, 9, 14, 20, 21) had homeology conserved in GCC. Of the GCA pairs that are grouped (GCA [4, 8], [5, 17], [10, 11] and [12, 13, 15]), most kept the number of signals in GCC (GCA [5, 17], [10, 11] and [12, 13, 15]). The remaining chromosomes are rearranged in the GCC karyotype. Analysis of both populations of the G. carapo cytotypes shows extensive karyotype reorganization. Along with previous studies, this suggests that the different cytotypes analyzed here may represent different species and supports the hypothesis that G. carapo is not a single widespread species, but a group of cryptic species.

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The monophyly of Crenuchinae and description of two new species ofPoecilocharax(Teleostei: Crenuchidae) based on phenotypic and genotypic evidence

Ohara

Pastana

Camelier

2022

Zoological Journal of the Linnean Society

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Crenuchinae is a subfamily of the fish family Crenuchidae distributed in the Amazon Basin with pronounced sexual dimorphism and exuberant colour patterns. Recent fieldwork in the tributaries of the Rio Aripuanã drainage, a large tributary of the Rio Madeira (Amazon Basin), resulted in the discovery of two distinctive, undescribed species of the crenuchin genus Poecilocharax, which are formally described herein, combining morphological and molecular data. These are the first representatives of Crenuchinae discovered after a gap of 57 years and the first records of Poecilocharax from the tributaries of the right bank of the Rio Amazonas draining the Brazilian crystalline shield. Based on a taxonomic review including all species of the subfamily, we provide an expanded morphological diagnosis for Crenuchinae. This now includes characteristics related to the lateral-line canals of head and body, the number of dorsal-fin rays and sexually dimorphic traits. In addition, we review previous characteristics used to diagnose Crenuchus and Poecilocharax, providing comments on their polarity and distribution across the subfamily. A dichotomous key is provided for the first time for species of Crenuchinae.

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Two New Species of Gymnotus (Gymnotiformes: Gymnotidae) from Brazil and Historical Biogeography of the Subgenus Lamontianus

Cited by 3 publications

References 47 publications

Characterization of the agonistic behavior of the weakly electric fish Gymnotus sylvius

Characterization of the agonistic behavior of the weakly electric fish Gymnotus sylvius

Chromosome Painting in Gymnotus carapo “Catalão” (Gymnotiformes, Teleostei): Dynamics of Chromosomal Rearrangements in Cryptic Species

The monophyly of Crenuchinae and description of two new species ofPoecilocharax(Teleostei: Crenuchidae) based on phenotypic and genotypic evidence

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