DNA barcoding reveals cryptic species in the sea slater (Crustacea, Isopoda) from Tunisia.

Barcoding studies have provided significant insights into phylogenetic relationships among species belonging to the genus (Crustacea, Isopoda). Herein the diversity of the Italian sea slater from Tunisia is studied for the first time. Samples were collected from 18 localities in Tunisia, and the analysis included previously published sequences from Italy and Greece available in GenBank. Bayesian and Maximum Likelihood phylogenetic analyses were carried out using a fragment of the mitochondrial COI gene. Putative cryptic species were explored using the 'barcode gap' approach in the software ASAP. A genetic landscape shape analysis was carried out using the program Alleles in Space. The analyses revealed highly divergent and well-supported clades of dispersed across Tunisia (Clades A1 and A2), Greece (Clade B) and Italy (Clades C1 and C2). High genetic dissimilarity among clades suggested that constitute a cryptic species complex. Divergence among different lineages (Clades A, B and C) occurred around 7-4.5 Ma. The detected high genetic distances among clades did not result from atypical mitochondrial DNAs or intracellular infection by bacteria. The complex history of the Mediterranean Sea appears to have played a significant role in shaping the phylogeographic pattern of . Additional morphological and molecular studies are needed to confirm the existence of cryptic species in in Mediterranean.