A new species of genus Psalidodon Eigenmann, 1911

A new species of genus Psalidodon Eigenmann, 1911 related to the P. paranae complex (Characiformes Characidae) from Upper Paranaíba river basin, Brazil, supported by genetic and morphometric data

Rosana de Mesquita Alves; Igor Henrique Rodrigues de Oliveira; Rubens Pasa; Karine Frehner Kavalco

The genus Psalidodon Eigenmann, 1911 (Characiformes Characidae) is a fish group with great diversity, expressed at the chromosomal, genetic and taxonomic level. The genus is markedby events of allopatric and vicariant evolution, by the formation of complexes of species andby wide geographical distribution. Both in these fish and other organisms, the association ofstudies with molecular markers and geometric morphometric techniques are useful in delimitingsignificantly evolutionary units (ESU). In this work, we performed maximum likelihood esti-mates (MLE) from mitochondrial Cyt b gene sequences and canonical variables (CVA) from13 landmarks in eight populations of P. aff. paranae Eigenmann, 1914. The analysis of Max-imum likelihood resulted in the structuring of populations in two different clades, one of whichwas composed only of individuals from a small population inhabiting a stream with approxi-mately two km of length, demonstrating their clear distinction from the other populations. Theanalysis of canonical variation demonstrated the complete structuring of this population, andthe position of each clade in the morpho-space was congruent with the topography observedin the MLE. Based on the results found, the existence of a new endemic species of the genusPsalidodon is evident.

2020, Biodiversity Journal

Distribution and morphological diversity of Astyanax rivularis

Distribution and morphological diversity of Astyanax rivularis Lütken, 1874 (Teleostei Characiformes) in the upper São Francisco River basin, Brazil

Rubens Pasa, Caroliny Helena Moreira Fernandes, Renan Rodrigues Rocha, Karine Frehner Kavalco

Astyanax S.F. Baird et Girard, 1854 (Teleostei Characiformes) is one of the most well characterized of the neotropical ichthyofauna and is composed of fish with great ability to adapt to different environmental conditions and a wide spectrum of interaction in fish assemblages due to its structure and population density. This study presents the geographical distribution and morphological diversity of Astyanax rivularis Lütken, 1874, a fish historically complex and extremely diverse, in tributary streams of the left side of upper São Francisco River.

Biodiversity Journal

2019, 10 (4): 307–314

Morphological and Genetic Structure of Two Equivalent Astyanax Species

Morphological and Genetic Structure of Two Equivalent Astyanax Species (Characiformes: Characidae) in the Region of Paranaíba Arc

Renan Rodrigues Rocha, Rosana de Mesquita Alves, Rubens Pasa, Karine Frehner Kavalco

The Astyanax scabripinnis complex is composed of a large number of almost morphological indistinguishable species, including Astyanax paranae and Astyanax rivularis, which exist in the Paraná and São Francisco Basins, respectively, and sometimes are considered subspecies of the A. scabripinnis group or even are cited just as A. scabripinnis. The two river basins are separated by the Upper Paranaíba Arc, likely the main cause of the isolation of these species. We used geometric morphometric tools and DNA analyses of populations of both species to identify the differences between them. Geometric morphometrics separated the two species into distinct groups, whose main difference was the body depth. This is generally related to the speed of the water flow in the river basins. The maximum likelihood phylogram based on mitochondrial DNA sequences formed two main clades: one composed of the population of A. rivularis and the other, of A. paranae. In the haplotype network, the species were similarly separated into two groups from the same ancestral haplotype, with A. rivularis dispersing into two lineages in the São Francisco River Basin. The distribution of A. paranae is a consequence of a secondary dispersion event in the Paraná River Basin. It forms two lineages from a haplotype derived from the ancestor. The vicariant effect of separate basins, through the elevation of the Upper Paranaíba Arc, led to the allopatric speciation of the populations originating the present species. The results of geometric morphometrics and molecular data of the fish show the importance of this geological event in the biogeography and evolutionary history of the ichthyofauna of the region and indicate that the isolation of these species seems to be effective.

The Scientific World Journal

Volume 2019, Article ID 6507954, 8 pages https://doi.org/10.1155/2019/6507954