A new species and a new record of Pelthydrus Orchymont, 1919 from Yunnan, China (Coleoptera: Hydrophilidae: Hydrophilinae) Author Zhu, Bingyue Author Ji, Lanzhu Author Bian, Dongju text Zootaxa 2018 2018-06-20 4438 1 189 194 journal article 29846 10.11646/zootaxa.4438.1.12 21b9288c-7301-4b31-9fe1-6397eef9709f 1175-5326 1294265 5914EBFF-4C15-47B8-8866-50AD03D7E297 Key to species of the Pelthydrus sculpturatus group 1. Mentum smooth, shiny with a few independent deep punctures, lateral margins of pronotum straight ........................................... 2 - Mentum with dense punctures, lateral edges of pronotum curved along anterior half ..................................................................... 5 2. Posterior margin of pronotum slightly wider than anterior margin; apex of parameres rounded ..................................................... 3 - Posterior margin of pronotum distinctly wider than anterior margin, apex of parameres oblique and truncated ............................. 4 3. Median lobe shorter than parameres, whose apex slightly pointing towards midline ..................................... Pelthydrus siamensis - Median lobe longer than parameres, and parameres gradually narrowed from base towards apices ..................................... P. tongi 4. Phallobase longer than parameres; gonopore situated at subapical portion ................................................................ P. sculpturatus - Phallobase shorter than parameres; gonopore located in the apical position ...................................................... P. ruiliensis sp. nov. 5. Smaller sized species (BL: 2.00– 2.30 mm ); apices of elytra narrowly rounded, not meeting at midline ...................... P. kapitensis - Larger sized species (BL: 2.80–3.10 mm ); apices of elytra continuously rounded, meeting at midline .......................................... 6 6. Ground punctures evenly distributed on the pronotum, microreticulation visible; parameres slightly exceeding median lobe ........ ............................................................................................................................................................................................... P. ovalis - Ground punctures more densely distributed on sides of pronotum, microreticulation almost invisible; median lobe slightly exceeding parameres ............................................................................................................................................................ P. iniquus