Deep genetic divergence in giant red shrimp Aristaeomorpha foliacea (Risso, 1827) across a wide distributional range

The giant red shrimp, Aristaeomorpha foliacea, is a commercially important species in the Mediterranean Sea (MED), Mozambique Channel (MOZ), and north western Australia (AUS). 685 bp of the mitochondrial COI gene was sequenced in 317 individuals from six Mediterranean and two Indian Ocean localities. Genetic diversity estimates of Indian Ocean samples were higher than those of MED counterparts. AMOVA, phylogenetic tree, haplotype network and Bayesian assignment analyses detected three haplogroups, corresponding to MED, MOZ and AUS, separated by three and 38 mutational steps, respectively. Within MED shallow genetic divergence between populations was dependent on local oceanographical characteristics. Mismatch distribution analysis and neutrality tests provided a consistent indication of past population expansion in each region considered. Our results provide the first evidence of genetic structure in A. foliacea and suggest a scenario of allopatric speciation within the Indian Ocean that, however needs deeper examination.

► The giant red shrimp is an economically important marine resource.
► High levels of genetic diversity were detected in all regions considered.
► Three highly divergent mtDNA lineages were detected, suggesting allopatric speciation.
► Divergence is consistent with current hydrographical and oceanographical barriers.