Análise filogeográfica de Astyanax scabripinnis (Characiformes, Characidae) da região de Campos do Jordão (SP)

Abstract

The lambaris, which include small Astyanax scabripinnis fish, inhabit the headwaters of small streams, forming well known populational isolates. These populations are possibly inbred, presenting little or no gene flow and reduced size. It is believed that these characteristics have aided the fixation of a pronounced karyotypic variability, contributing to the elevated phenotypic plasticity observed between the populations. Due to these factors, this fish group has received special treatment, since they represent a species complex. However, despite abundant cytogenetic studies and all the attention granted to this group, such a polymorphism has not yet been verified on a molecular level and its phylogeny remains unresolved. The verification of whether the karyotypic variations found between the A. scabripinnis populations of the Campos do Jordão region also exist on a molecular level, the estimate of part of the current phylogenetic relationships between them and, also, the verification of whether there is any relationship between the presence or absence of B chromosomes in this species with the observed haplotypic diversity was possible through the analysis of the intraspecific genetic variation of a part of the mitochondrial cytochrome b. The results corroborate the hypothesis that these populations were in contact prior to the elevation of the Serra da Mantiqueira and that they are currently geographically separated. The phylogenetic relationships between the studied populations are discussed. The absence of evolutionary relationship between the cytochrome b gene and the supernumerary chromosomes of these populations was observed.