Artemesia longinaris is a marine shrimp endemic to the southwestern Atlantic and distributed from Rio de Janeiro (Brazil) to Chubut (Argentina). Phenotypic variations have been documented in populations along its distribution; investigations on the genetics of the fishing stocks were conducted covering its geographical range. Findings indicate a continuous gene flow among the populations analyzed, suggesting that the phenotypic variation is a consequence of different environmental conditions among the localities (Carvalho-Batista et al. 2014).