Endemic and sub-endemic water beetles of Mongolia and their distribution ranges Author Enkhnasan, Davaadorj Institute of Biology, Mongolian Academy of Sciences, Peace Avenue 54 b, Ulaanbaatar 13330, Mongolia enkhnasand@mas.ac.mn Author Boldgiv, Bazartseren Ecology Group, Department of Biology, National University of Mongolia, Ikh Surguuliin Gudamj 1, & Academy of Natural Sciences of Drexel University, Philadelphia, PA 19103, USA text Journal of Species Research 2019 8 4 395 406 journal article 10.12651/JSR.2019.8.4.395 2713-8615 13161488 Ochthebius mongolicus Janssens, 1967 ( Fig. 4 ) Diagnosis . Body length 2.5 mm . The anterior edge of the labrum swells in the middle. The anterior border of clypeus forming with its external sides a very marked angle. Foveoles of the inter-ocular space is very broad and almost confluent. Pronotum very depressed with re- spect to the disc; their denticulate outer sides forming a right angle forwards and extending towards the back in a long, non-denticulate re-entrant curve. The disc isolat- ed from the depression of the auricles by a longitudinal furrow; the median groove of the disc, reaching the anterior and posterior edges, divides it into two shiny patches, each of which bears two foveus, the anterior of which is smaller but more accentuated than the posterior. Head and the pronotum are copper in color and bear a rather abundant pubescence, the elytra are yellow and their pubescence is much rarer. The punctuation, although clear, is rather irregular and streaks are very poorly defined. The male genital framework is easy to recognize that is point- ed hook shape of the piece ( Janssens, 1967 ). Remarks . Ochthebius mongolicus Janssens, 1967:58 - [ Holotype ♂ (Hungarian National Museum, Budapest): Mongolia , Bayankhongor , 1,250 m , 25.vi.1964 , leg. Z. Kaszab].