DNA barcodes combined with geometric morphometry challenge species hypothesis in palaemonid shrimp

Although the Mediterranean Region is known as a hotspot for biodiversity and endemism its freshwater fauna still greatly unexplored, even emblematic taxa such decapods require in-depth integrative investigation. In our research we used approach composed of various geometric morphometric molecular methods to challenge taxonomic status two shrimps representing Palaemonidae: Palaemon antennarius minos . Basing on 352 COI sequences, three Molecular Operational Taxonomic Units (MOTUs) were defined. Two them belonged P. : first inhabiting Apennine Peninsula Sicily, second one from Balkan Peninsula. The third MOTU corresponded Crete. was closer in terms genetics, than other conspecific MOTU. carapace shape variation, studied 180 individuals, mainly explained by geographic distribution. Cretan groups clearly distinguished, while samples distributed along gradient Sicily southern Balkans. results study showed that, either assigned constitutes separate species or, alternatively, should be synonymised with