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.