Studies on intraspecific variability allow the verification of the effects of microevolutive forces on populations, improving the comprehension of the processes involved in speciation and population differentiation. Some studies have shown high genetic divergence among decapod Crustacean populations with wide geographic distribution, particularly for those inhabitants of the western Atlantic coast. Thus, individuals with wide latitudinal distribution in this environment represent great models to analyze this situation, such as the hermit crab Calcinus tibicen. This species also has a gap in its distribution that coincides with the Amazon River mouth. The freshwater volume that enters into the coast changes drastically the salinity of the region, which can represent an important physiological barrier for larval dispersion of this species among the Caribbean and South Atlantic populations. Therefore, morphological and genetic variation will be evaluated among the populations of Calcinus tibicen from Brazil and other regions throughout its distribution. The analysis will be conducted by morphological studies in adults, as well as molecular studies, using the mitochondrial genes 16S and COI. Then it will be possible to analyze the differences between individuals from the analyzed populations, as well as the relationship and the genetic distance among them, and to evaluate the percentage of the variation, verifying the level of genetic subdivision among them, and the potential existence of more than one species.
News published in Agência FAPESP Newsletter about the scholarship: