Marine provinces and the Amazon plume as barriers to gene flow in the Western Atlantic: the rock crab Menippe nodifrons Stimpson, 1859 (Decapoda: Brachyura) as a model

Abstract

Phylogeographic studies are of great importance for comprehension of the evolutionary history of the taxa, and decapod crustaceans have shown themselves as a great model to be used in this approach. An essential element to studies of variability and phylogeography is the categorization of geographic regions. Spalding et al. (2007) proposed the division of coast regions of the world in a system denominate Marine Ecoregion of the World (MEOW). This system consists of three main scales - realms, provinces, and ecoregions - that was determined based on distincts regional patterns established from variation on abiotics factors. An appropriate model which has been used in variability works are the crustaceans, above all species of wide distribution. Although, few studies looked into the patterns of variability and the relationship with the marine provinces in many parts of the world, which includes the Western Atlantic. That way, the present study searches understand if have genetic and/or morphological variation in the populations of Western Atlantic of the wide distribution crab specie Menippe nodifrons, and if the marine provinces and their determining factors, as the Amazonas plume, act as geographical barriers to the gene flow between the populations. The morphological and molecular analysis will be realized in the Laboratory of Bioecology and Crustacean Systematics (LBSC), developed from the material of Collection of Crustaceans of the Biology Department (CCDB), and from others collections, through borrowing and visits, and possible collect. Will be analyzed the morphological features already described in the literature and features that hadn't been described previously, but which may indicate variation at intraspecific and/or interspecific level. The obtaining of molecular data will comprise the steps of DNA extraction, amplification of two fragments of mitochondrial gene (Cytochrome Oxidase subunit I and 16S rRNA), purification of the samples, and sequencing. From sequences obtained and others already deposited on GenBank, will be constructed genetic distance matrix, haplotype networks and phylogenetic hypothesis which allow to understand the relationship between the specimens of the different marine provinces.