Phylogeographic patterns of decapod crustaceans at the Atlantic–Mediterranean transition

Abstract

Comparative multispecies studies allow contrasting the effect of past and present oceanographic pro- 30 cesses on phylogeographic patterns. In the present study, a fragment of the COI gene was analyzed in 31 seven decapod crustacean species from five families and with different bathymetric distributions. A total 32 of 769 individuals were sampled along the Atlantic–Mediterranean transition area in order to test the 33 effect of three putative barriers to gene flow: Strait of Gibraltar, Almeria–Oran Front and Ibiza Channel. 34 A significant effect of the Strait of Gibraltar was found in the crabs Liocarcinus depurator and Macropipus 35 tuberculatus. The Ibiza Channel had a significant effect for L. depurator. However, the Almeria–Oran front 36 was not found to have a significant effect on any of the studied species. Higher levels of population struc- 37 ture were found in shallow-water species, although the number of species sampled should be increased 38 to obtain a conclusive pattern. The haplotypes within the different species coalesced at times that could 39 be related with past climatic events occurring before, during and after the last glacial maximum. Given 40 the large diversity of phylogeographic patterns obtained within decapods, it is concluded that both his- 41 torical and contemporary processes (marine current patterns, bathymetry and life-history traits) shape 42 the phylogeographic patterns of these crustaceans.