Cryptic speciation in molluscs: to be or not to be the same species?
Many species of sea slugs are regarded as circumglobal occurring all around the World. Yet, these global distributions are not consistent with the idea of distinct biogeographic regions in the Oceans and pose serious challenges to understand how species disperse across vast spans of open water. This is the case of the flamboyant and beautiful tropical species Micromello undatus known across the Atlantic, Indian, and Pacific Oceans. Nevertheless, this assumption is based on morphological similarities and remains to be tested using DNA sequence data whether Micromelo undatus is in fact a single broadly distributed species or a complex of species of similar looking. In this study molecular phylogenetics and population genetic methods will be used (1) to test whether Micromelo undatus is one or several species, (2) how the various species or populations relate to each other, (3) where was the original distribution range of Micromelo undatus, and (4) what processes of marine speciation and biogeography explain the present distribution of this species complex.