Phylogeny and phylogeography of the family Hyalidae (Crustacea: Amphipoda) along the northeast Atlantic coasts

The family Hyalidae comprises more than one hundred species, distributed worldwide. They are common and abundant in the littoral and shallow sublittoral habitats and they play an important role in the coastal food chain. Most studies about this family were dealing with taxonomy and ecology, while very little is known about phylogenetic relationship among genera and species. In the present study we aim to achieve the first approach of the phylogenetic patterns of this family in NE Atlantic Ocean and Mediterranean Sea, and to perform the first insight into the phylogeography Apohyale prevostii along both the North Atlantic coasts. In order to do that, eight species belonging to the genera Apohyale, Hyale, Serejohyale and Protohyale were investigated using the mitochondrial COI-5P barcode region. Specimens were collected along European and Moroccan Atlantic rocky shores, including Iceland, the British Isles, Macaronesia and in the Mediterranean Sea. Sequences of A. prevostii, from the NW Atlantic Ocean, available in BOLD and GenBank, were retrieved. As expected, phylogenetic analyses showed highly-divergent clades, clearly discriminating among different species clusters, confirming their morphology-based identifications. Although, within A. perieri, A. media, A. stebbingi, P. (Protohyale) schmidtii and S. spinidactylus, high genetic diversity was found, revealing putative cryptic species. The clade of A. prevostii and A. stebbingi appears well supported and divided from the other two congeneric species, and P. (Protohyale) schmidtii shows a basal divergence. The north-western Atlantic coasts were recently colonized by A. prevostii after the last glacial maximum from the European populations showing also a common haplotype in every population analysed. The use of the COI-5P as DNA barcode provided a good tool to underline the necessity of a revision of this emblematic family, as well as to discern taxonomically the possible new species flagged with this molecular device.