Investigating the molecular systematic relationships amongst selected P lesionika ( D ecapoda: P andalidae) from the N ortheast A tlantic and M editerranean S ea

Abstract

Despite the high number of species and ecological diversity of pandalid shrimps, there has been no previous attempt to resolve evolutionary relationships of several genera using molecular tools. Although mitochondrial DNA cytochrome oxidase I ( COI ) is widely used in barcoding studies to delimit species boundaries, additional insights into phylogenetic affinities can be obtained, especially when used in combination with data from additional genes. The knowledge of molecular diversity is essential to understand phylogenetic relationships and will help systematic clarifications. Based on partial fragments of the 16 S and COI genes, we have focused specifically on addressing the systematic relationships of the economically and ecologically important shrimp genus P lesionika within a framework of five genera from within the P andalidae. Our results showed that species within P lesionika are substantially divergent when compared with other genera, exhibiting the highest average nucleotide divergence, with 0.1123 and 0.0846 in COI and 16S genes, respectively. In addition, sequence divergence was found to vary greatly within the genus P lesionika ( COI /16 S ): 0.0247/0.0016 between P lesionika antigai and P lesionika heterocarpus and 0.1616/0.098 between P lesionika heterocarpus and P lesionika edwardsii . We did not find amino acid sequence divergence between P . heterocarpus and P . antigai compared with P . heterocarpus and P . edwardsii (8.10%, K 2 P distance). Three species of P lesionika ( P . antigai , P . heterocarpus and P lesionika scopifera ) appear well separated from other P lesionika species in both maximum likelihood and B ayesian analyses. The present study confirms the utility of COI over 16 S as a genetic marker to resolve relationships between different species of P lesionika from the N ortheast A tlantic and M editerranean S ea, in addition to species delimitation. The findings highlight the need to further review paraphyly within P lesionika in an attempt to recognize a concordance in the evolutionary history of P lesionika with major ecological and geological events.

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