Sclerites of Bursa Copulatrix Reveal Hidden Generic Diversity in Dimini (Coleoptera, Elateridae): Revision of Parapenia Species from China, with the Establishment of Three New Genera

The genus <i>Parapenia</i> Suzuki from China is revised, with 12 species recognized, including six new species: <i>P. fuxi</i><b>sp. nov.</b>, <i>P. nyuwa</i><b>sp. nov.</b>, <i>P. pangu</i><b>sp. nov.</b>, <i>P. ruihangi</i><b>sp. nov.</b>, <i>P. wuchaoi</i><b>sp. nov.</b>, and <i>P. zhengi</i><b>sp. nov.</b> In addition, <i>P. sausai</i> Schimmel and <i>P. villosa</i> (Fleutiaux) are newly recorded from China, and <i>P. jagemanni</i> Schimmel <b>syn. nov.</b> is synonymized with <i>P. yunnana</i> Schimmel. Large plate-like sclerites in the bursa copulatrix are consistently present in <i>Parapenia</i> and show diagnostic value for generic delimitation. Comparative morphological studies, particularly of these sclerites, justify the establishment of three new genera distinct from <i>Parapenia</i>: (1) <i>Parapenioides</i><b>gen. nov.</b>, including <i>P. zidani</i><b>sp. nov.</b>; (2) <i>Megapenia</i><b>gen. nov.</b>, including <i>M. cruciata</i> (Bouwer) <b>comb. nov.</b>, type species <i>M. marginalis</i> (Fleutiaux) <b>comb. nov.</b>, and <i>M. tianlongi</i><b>sp. nov.</b>; and (3) <i>Sinopenia</i><b>gen. nov.</b>, including <i>S. significata</i> (Schimmel) <b>comb. nov.</b> A comparative diagnostic table of the four genera, together with a checklist and distribution maps, is provided. Identification keys to Chinese species of <i>Parapenia</i> and <i>Megapenia</i> are also included. This study clarifies the taxonomic complexity of <i>Parapenia</i> and emphasizes the overlooked significance of sclerotized structures in the bursa copulatrix for distinguishing genera within Dimini.