Integrative taxonomy and analysis of species richness patterns of nocturnal Darwin wasps of the genus Stephens (Hymenoptera, Ichneumonidae, Ophioninae) in Japan.

The predominantly tropical ophionine genus Stephens, 1835 is one of the largest genera of Darwin wasps (Hymenoptera, Ichneumonidae), with more than 700 extant species worldwide that are usually crepuscular or nocturnal and are parasitoids of Lepidoptera larvae. In the present study, the Japanese species of are revised using an integrative approach (combined morphology and DNA barcoding). On the basis of 3,110 specimens, 47 species are recognised in Japan, eight of which are new species ( Shimizu, , Shimizu, , Shimizu, , Shimizu, , Shimizu, , Shimizu, , Shimizu, , and Shimizu, ), seven are new records from Japan ( Tang, 1990, (Enderlein, 1921), Chiu, 1954, , Tang, 1990, Cushman, 1937, (Smith, 1858), and Chiu, 1954, ), 32 had already been recorded in Japan; three ( Townes, Townes & Gupta, 1961, (Morley, 1912), and (Gravenhorst, 1829)) have been erroneously recorded from Japan based on misidentifications, and four names that were previously on the Japanese list are deleted through synonymy. The following taxonomic changes are proposed: Gauld & Mitchell, 1981, (= (Uchida, 1928)); ; Cameron, 1899, = (Roman, 1913), = Chiu, 1954, = Chiu, 1954, = Viktorov, 1957, = Townes, Townes & Gupta, 1961, = Rao & Nikam, 1969, = Rao & Nikam, 1970, (= (Smith, 1874)); Chiu, 1954, (= (Matsumura & Uchida, 1926)); Chiu, 1954, (= (Uchida, 1928)); (Uchida, 1930), (= (Uchida, 1928)); Chiu, 1954, (= (Uchida, 1928)); and = Chao & Tang, 1991, In addition, the following new regional and country records are also provided: (Kirby, 1900), , and from the Eastern Palaearctic region, from the Eastern Palaearctic and Oceanic regions, and (Uchida, 1928) from the Oriental region; (Szépligeti, 1906) from Nepal, from Laos, from Laos and Malaysia, (Smith, 1860) from Taiwan, from India and Philippines, Cameron, 1903, (Matsumura & Uchida, 1926), and from Indonesia, from 14 countries (Australia, Bhutan, Brunei, Indonesia, Laos, Malaysia, Nepal, New Caledonia, Papua New Guinea, Philippines, Solomon Islands, Sri Lanka, Tajikistan, and Taiwan), and from South Korea. An identification key to all Japanese species of is proposed. Although 47 species are recognised in the present study, approximately 55 species could potentially be found in Japan based on ACE and Chao 1 estimators. The latitudinal diversity gradient of species richness is also tested in the Japanese archipelago based on the constructed robust taxonomic framework and extensive samples. species richness significantly increases towards the south, contrary to the 'anomalous' pattern of some other ichneumonid subfamilies.