Abstract
Hydroporus esseri sp. n. is described from the Koprulu Canyon near Sagirin in southern Turkey (Antalya province), where it was found in a backwater pool of the Koprulu River. It is the smallest species of the genus Hydroporus Clairville, 1806 recorded so far from Turkey. Morphologically the new species is very close to Hydroporus umbrosus (Gyllenhal, 1808), which is widespread in North and Central Europe, Siberia and Far East. H. esseri sp. n. can be separated from H. umbrosus chiefly by its smaller size, the shape of the median lobe and surface colour. The aedeagi and habitus of both species are illustrated. Notes on their distribution and life habitats are given. Hydroporus memnonius Nicolai, 1822 is recorded for the first time from Turkey, and H. umbrosus for the first time from Slovakia. Altogether 180 species of the genus Hydroporus are now reported world-wide and 34 from Turkey.
NSTL