Variabilidade fenotípica e genotípica do camarão Macrobrachium jelskii (Miers, 1877) das Bacias do Nordeste Brasileiro: uma abordagem de sistemática integrativa

Abstract

Macrobrachium jelskii is a widely distributed species in northeastern Brazil, occurring throughout South America. However, no studies on phylogeography, local morphological variations and genetic variability of the populations of this species were carried out. This prawn species can reveal important information on the dispersion pattern and related vicariates for scenarios of past tectonic arrangements and other events that have influenced the biogeography of the aquatic taxa. The aim of this manuscript is to investigate a phenotypic and molecular diversity of the prawn M. jelskii populations in the Mid-Northeast Caatinga, Maranho Piauí and São Francisco ecoregions, influenced by past scenarios and environmental local responses. This scientific article uses an approach of Integrative Systematics, a multivariate geometric morphometry, phylogenetic analyzes and genetic structuring. Geometric morphometry showed evident sexual dimorphism, in which females presented cephalothorax and abdomen more horizontally stretched. This possibly favors gonadal development, vitellogenesis and egg storage. Abstraction of the shape of the three body planes does not demonstrate a consensus on the structuring of the populations between M. jelskii in the Northeast of Brazil. This fact corroborates a low nucleotide and haplotype diversity, in which only one haplotype was shared among the populations of the basins. Thus, ratifying a possibility of introduction in the Northeast area by DNOCS. In addition, the genetic data reported a presence of noises and double peaks not electropherogram, which represents co-amplification of mitochondrial pseudogenes of the region Cytochrome Oxidase I, little reported in the literature for the genus Macrobrachium. This fact show a precedent of mistrust for published phylogenetic and phylogeographic relationships, which recently did not depict this. Knowing that this characteristic can generate an overestimation of evolutionary lineages and, thus, erroneous conclusions on dispersive, vicarious or speciation events, it is of importance to report the cases of pseudogenes and the use of specific molecular primers for each taxon.