A Japan-focused review of East Asian Acicnemis Fairmaire, 1849 (Coleoptera, Curculionidae) reveals cryptic diversity in a well-studied region

The East Asian species of Acicnemis Fairmaire, 1849 (Coleoptera: Curculionidae: Molytinae) are reviewed using a combination of traditional morphological approaches (microscopy, dissections) and DNA barcoding. Three new species, A. cryptica Lewis & Kojima, sp. nov., A. koguma Lewis & Kojima, sp. nov. and A. squamata Lewis & Kojima, sp. nov. are described from mainland Japan. The former two species are cryptic and sister to more widespread, previously described taxa.

Based on examination of name-bearing type material and morphological considerations Acicnemis cruciata Kleine, 1924 syn. nov. is a junior subjective synonym of Acicnemis postica Hubenthal, 1919, Acicnemis yakushimana Morimoto & Miyakawa, 1995 syn. nov. is a junior subjective synonym of A. dividicincta Morimoto & Miyakawa, 1995, and Acicnemis dorsonigrita Voss, 1941 syn. nov. is a junior subjective synonym of Acicnemis palliata Pascoe, 1872.

Lectotypes are designated for Acicnemis albofasciata (Ter-Minasian, 1953), A. laeta Hubenthal, 1919, A. postica Hubenthal, 1919 and A. sauteri Hubenthal, 1919. Important morphological characters used in Acicnemis species identification are reviewed and a key to the East Asian species is provided. DNA (CO 1) barcoding is used to supplement our morphology-based species hypothesis, and the first published barcodes for most species covered here are presented.