Statistical parsimony network analysis (TCS algorithm) based on 64 partial mitochondrial COI sequences (347 bp). This analysis included specimens of Neritina meleagris and Neritina virginea from the Caribbean and Brazilian Provinces. Size of the circle is proportional to frequency of the haplotype and colours inside the circles designate geographical locations to which the samples belong. Black circles correspond to hypothetical haplotypes. The number of mutational steps is indicated by dashes on branches. We highlighted the 36 mutational steps that separate the two species haplotypes.