57º Congresso Brasileiro de Genética
Resumos do 57º Congresso Brasileiro de Genética • 30 de agosto a 2 de setembro de 2011
Centro de Convenções do Hotel Monte Real Resort • Águas de Lindóia • SP • Brasil
www.sbg.org.br - ISBN 978-85-89109-06-2
136
Molecular phylogeography of the
group Astyanax bimaculatus (Teleostei,
Characiformes) from Paranaíba, São Francisco
and Coastal river basins of Brazil
Kavalco, KF1; Pazza, R1; Penteado, PR1; Dergam, JA2
Laboratório de Genética Ecológica e Evolutiva, UFV - Campus de Rio Paranaíba, MG. 2Laboratório de Sistemática
Molecular “Beagle”, Departamento de Biologia Animal, UFV, MG.
[email protected]
1
Keywords: Astyanax lacustris, Astyanax bimaculatus, Astyanax altiparanae, Phylogoegraphy, mtDNA
The fishes popularly known as “yellow-tailed tetras” are widespread in the Neotropics. In the last decades, some
morphotypes within the Astyanax bimaculatus species complex were subject to systematic revisions and were considered valid species. Such was the case in A. altiparanae from the Upper Paraná River Basin and A. lacustris from
the São Francisco River Basin. On the other hand, the coastal populations of this species complex have not been
included in systematic revisions. The aim of the present work was to characterize the molecular signals of dispersal
and vicariant events that affected the populations of the complex. We analyzed samples from the São Francisco,
Paraíba do Sul, Doce, Mucuri, and Paranaíba river basins and other smaller coastal basins, comprising 41 collection
sites (N=70 individuals). The populations’ phylogeography was inferred using the mtDNA gene ATPase6/8. There
were sequenced 798 sites from the position 82 of this gene and 77 sites were polymorphic. Thirty-two haplotypes
were observed, haplotypic diversity Hd was estimated at 0.945 and the nucleotide diversity Pi=0.02693. The number of nucleotide changes was k = 21.140. Four independent haplotype networks were obtained (connection limit
set at 95%), and connections represent one nucleotide substitution. This corroborates the Maximum Likelihood
dendrogram. Two principal clades were observed, whereas some subclades showed strong geographic correlation.
Within Clade 1, subclade 1A included only fishes from Paranaíba River, while the subclade 1B included specimens
from Paranaíba, São Francisco, Doce e Paraíba do Sul rivers. Within Clade 2, the subclade 2A was extremely structured, and it was composed exclusively of fishes from the Paraíba do Sul River. The subclade 2B was composed by
samples from Doce, Mucuri and other northerly coastal rivers. Considering that yellow-tailed tetras are characterized
by highly structured populations our results indicate that the ATPase fragment is able to recover a good fraction of
the species evolutionary history in southern and central Brazil. The pattern observed also suggest that vicariance
events have played a strong role in the evolution of small-sized fishes, adding relevant information to the traditional
knowledge that southern South America harbors several examples of allopatric speciation in fresh-water fishes.
Financial support: FAPEMIG (CBB - 00317-08).