Genus Ochthebius (Hydraenidae, Coleoptera) comprises numerous species complexes recorded in the Western and Central Mediterranean area, with highly complex taxonomy. Many of these species are local endemics and therefore of special conservation interest. However, Eastern-Adriatic region was not included in integrative taxonomic investigations of Hydraenidae so far, despite being known as a biodiversity hot-spot area for numerous freshwater invertebrate taxa. Within the project, a comparative collection of Ochthebius specimens, collected in specific hypersaline habitats on the mainland coast and islands, will be established. Specimens will be examined based on standard morphological characters, and compared to specimens deposited in water beetles collections of the natural history museums. Multilocus and genome-wide SNP marker sets will be developed. Generated molecular datasets will be used in the delineation of species complexes and in phylogenomic analyses, with the aim to establish phylogenetic and population-genetic hypotheses and evolutionary scenarios for Eastern-Adriatic Ochthebius taxa. A comprehensive taxonomic revision of specific groups within the genus will be carried out according to integrative-taxonomic approach. The results will greatly contribute to general knowledge about systematics and taxonomy of the family Hydraenidae in Eastern-Adriatic area, possibly resulting with discovery of cryptic taxa within the particular species complexes. New taxonomist will be trained. The utilization of the advanced phylogenomic methods will have great impact for the development of standardized molecular protocols for species identification within the species complexes of water beetles. In addition, the results will provide a basis for biodiversity monitoring and effective conservation of potentially endangered aquatic habitats and accompanying invertebrate fauna in the Eastern-Adriatic biodiversity hot-spot region.