The systematic position of the ground beetle Pterostichus kiangsu Jedlička (Coleoptera: Carabidae)

Rhagadus Motschulsky is an East Asian endemic, predominantly flightless subgenus of Pterostichus Bonelli, currently comprising eight recognised species distributed throughout the Japanese Archipelago and surrounding regions. Mainland China had been excluded from its distribution because previous Chinese records were based on misidentified or incorrectly assigned species. Examination of the holotypes of several Chinese endemic Pterostichus species revealed that P. kiangsu Jedlička, previously not assigned to Rhagadus, belongs to this subgenus because, although it has rounded pronotal hind angles unlike almost all other members of Rhagadus, its male genitalia, particularly the endophallus, possesses all diagnostic characters of the subgenus. Accordingly, mainland China is confirmed as part of the distribution of Rhagadus on the basis of unambiguously identified specimens. In addition, the following new synonymy is proposed: P. kiangsu = P. chinkiangensis Kirschenhofer syn. n. A morphological phylogenetic analysis placed P. kiangsu near the clade comprising P. thorectes Bates, P. thorectoides Jedlička, P. negylopus Sasakawa, and P. solskyi (Chaudoir), although support for this placement was insufficient to establish its phylogenetic position conclusively. Some unique external and genitalic characters of P. kiangsu, together with its isolated distribution, suggest that additional species closely related to P. kiangsu but morphologically less differentiated may remain undiscovered in eastern China. An updated key to the species of Rhagadus, incorporating P. kiangsu, is provided.http://www.zoobank.org/urn:lsid:zoobank.org:pub:FBBB3816-0A08-4638-B764-5FDF8922B7C9