RELAÇÕES FILOGENÉTICAS E FENÉTICAS ENTRE ALGUMAS ESPÉCIES BRASILEIRAS DO GÊNERO ACHIRUS (PLEURONECTIFORMES: ACHIRIDAE) BASEADAS NO ESTUDO DE ISOENZIMAS

Resumo

Phenetic and cladlstic analyses were made on genetic data obtained by starch gel electrophoresis of isoenzymes in order to produce phylogenetic hypotheses for 5 species of Achirus, and 7 others species (used as outgroup) of 4 genera from 3 families of pleuronectiform fishes from the coast of Paraiba and the Tocantins river (State of Pará). Ten enzyme systems were analyzed as the result of the translation of 15 gene loci. For the phenetic analysis, a matrix of pairwise genetic identities was computed from which an UPGMA dendrogram was constructed. For the cladlstic analyses, two different approaches were used: the first one was to consider the allele as a binary character, which was analyzed using a Wagner parsimony algorithm ("implicit enumeration" analysis of the HENNIG 86 program); the other approach was to use the locus as a character, and treat the alleles as its different states in a transformation series, where mutation, fixation and elimination of each allele were treated as evolutionary novelties, and the heterozygotes were used as clues for the ordering of the series. The phylogenetic position of the species of Symphurus, Citharichthys and Etropus, as well as the relationships between these species and the group Achirus-Thnectes were the same
both in the phenetic and in the cladlstic analyses. Conversely, the position of A. achirus and Thnectes paulistanus in relation to the other four species of Achirus studied was ambiguous, depending on the approach used. In this case the transformation series analysis produced the tree which, together with one of the two most parsimonious Wagner trees, was most consistent with the conventional taxonomy of the family. Two species of Achirus and one of Citharichthys, collected in the State of Pará, are different from those of Paraíba and probably represent three new species.