Genetic and phenotypic variability in populations of the Macrobrachium amazonicum complex: New findings to the upper Paraná Hydrographic Basin

Abstract

Our study investigates the genetic and phenotypic variability of two populations of shrimps of the Macrobrachium amazonicum complex from two rivers of the same hydrographic basin in southeastern Brazil. We tested the hypothesis that the two hololimnetic populations are composed of different species from M. amazonicum complex. We identified, sexed, measured the specimens, and collected the genetic material for molecular analysis. We realized a meta-analyzes with other populations data from a bibliographic survey based on compilation of sex ratio and carapace length from 22 populations. Considering the molecular phylogenetic analysis, COI DNA fragments were used to generate a phylogenetic tree and haplotype network. A total of 703 individuals was sampled in the Araguari River and 808 individuals in the Grande River. In the Araguari River population, females were larger than males and no male morphotypes observed. While in the Grande River population, no differences in body size between sexes were observed, but the male morphotypes were present. Our results showed that the shrimps sampled in Araguari River belong to the species M. pantanalense, based in molecular, morphological and population evidences. In turn, the population of shrimps sampled in Grande River presents similar characteristics to M. amazonicum. Our findings contribute to the knowledge of phylogeography of the species of M. amazonicum complex and to expand the distribution range of M. pantanalense in Paraná Hydrographic Basin.