Using morphometry of otolith for the identification of three sympatric and morphologically similar species of Astyanax from the Atlantic Rain Forest of Argentina

AVIGLIANO, ESTEBAN; EUGENIA ROLON; JUAN JOSÉ ROSSO; EZEQUIEL MABRAGAÑA; ALEJANDRA VANINA VOLPEDO

ENVIRONMENTAL BIOLOGY OF FISHES

SPRINGER

Lugar: Berlin; Año: 2018 vol. 101 p. 1319 - 1328

0378-1909

In several genera, the otolith shape is species-specific and the use of this structureprovides a useful tool aiding in the species identification. In many studies regardingNeotropical fish fauna, species of the genus Astyanax are commonly identified at thegenus level, mainly due to the phenotypic plasticity of the morphological characterstraditionally used for species determination. In consequence, additional tools intendedto better elucidate the taxonomic boundaries between species of Astyanax arecertainly needed. In the last decade, the shape of otoliths has allowed to discriminateamong closely related species. In this work, Fourier descriptors and shape indices oflapilli otolith were evaluated for the discrimination among three sympatric species ofgenus Astyanax inhabiting streams of the Atlantic Rain Forest (Argentina). Aspectratio, roundness and ellipticity of otoliths were significantly different between thespecies (p<0.05) while, no significant differences were found for circularity,rectangularity and form factor (p>0.05). PERMANOVA analysis reveal significantdifferences between species using Fourier descriptors (F=96.7, 0.0001<p<0.02) andthe reclassification rates of quadratic discriminant analysis were high, averaging 86.3%(82.7% and 88.6%). Multivariate analyses of shape indices were not effective todiscriminate between species. Instead, high classification percentages suggest that theotolith outline is a potential tool for the identification of sympatric morphologicallysimilar species of Astyanax. Our results could contribute to future taxonomic andphylogenetic studies and may be an interesting input for both paleontological andtrophic studies in sympatric species.