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

• Published in: Zebrafish Vol. 18; no. 2; p. 162
• Main Authors: Braga, Gisele S F, Ferreira, Daniela C, Marques, Débora K S, Centofante, Liano, Carvalho, Fernando R, Venere, Paulo C
• Format: Journal Article
• Language: English
• Published: United States 01-04-2021
• Subjects: Adaptation, Physiological; Animals; Brazil; Ecosystem; Gymnotiformes - genetics; Brazil; upper Paraguay River basin; tuvira; Gymnotus pantanal; Gymnotus sylvius; cytochrome oxidase I
• ISSN: 1557-8542
• DOI: 10.1089/zeb.2020.1908

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
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
,
, and
. However, the results revealed that the molecular operational taxonomic units identified as
actually include a relatively diverse set of fish, separated by considerable genetic distances. As the
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
These findings emphasize the importance of using an integrative approach for a more accurate diagnosis of
, in particular, the species marketed as live bait for the fisheries of the upper Paraguay River basin in the Brazilian Pantanal.