Annotated checklist of the minute moss beetles (Insecta: Coleoptera: Hydraenidae) of Croatia, with two lectotype designations

This is the first annotated checklist of the Hydraenidae of Croatia. It is based on reliable literature data and the examination of unpublished specimens identified by the authors. A total of 65 species is confirmed to occur in Croatia: 26 species of Hydraena Kugelann, 1794, nine species of Limnebius Leach, 1825, and 30 species of Ochthebius Leach, 1815. With regard to the biogeographical regions of Croatia, 47 of these species are found in the Mediterranean Region, 28 in the Continental and 14 in the Alpine Region. Four species are recorded from Croatia for the first time: Hydraena (s. str.) assimilis Rey, 1885, Limnebius (s. str.) aluta Bedel, 1881, Ochthebius ( Asiobates ) flavipes Dalla Torre, 1877, and O. (s. str.) pedicularius Kuwert, 1887. Four species are classified as “unconfirmed or doubtfully recorded” from Croatia. Ochthebius ( Asiobates ) bicolon Germar, 1824 is deleted from the Croatian checklist. An additional 29 species that potentially could occur in this country are discussed. Only one hydraenid species, Hydraena angustata Sturm, 1938, is currently regarded as endemic to Croatia, but it is assumed to be more wide-spread. A total of 14 Croatian hydraenid species is regarded as endemic or subendemic to the Balkan Region. Lectotypes are designated for Hydraena (s. str.) croatica Kuwert, 1888 and Ochthebius ( Aulacochthebius ) narentinus Reitter, 1885. A photograph of the dorsal habitus of H . (s. str.) croatica is published for the first time. The history of the exploration of the Hydraenidae of Croatia is outlined. Compared to other South European countries like Spain or Italy, the knowledge of the hydraenid fauna of Croatia is still remarkably poor, and very few Croatian hydraenid specimens have been barcoded so far; only one specimen was found databased in BOLD and GeneBank (accessed June 2025).