Melalgus japonicus Chûjô, 1973

Jerzy, Borowski, 2022, Taxonomic changes in Bostrichidae (Insecta, Coleoptera), Zootaxa 5154 (5), pp. 590-594 : 590

1. Melalgus japonicus Chûjô, 1973 and Melalgus batillus ( Lesne, 1902)

M. japonicus was described by a Japanese entomologist M. Chûjô from Tsushima Island ( Chûjô 1973) based on a single male. The author provided the species description in Japanese, but the article contains two photographs of M. japonicus and Latin names, including the name of the new species. As M. japonicus was described in a magazine of local circulation, not easily available, the species was not included in the world’s catalogue of the Bostrichidae ( Borowski & Węgrzynowicz 2007) . For the same reasons the species was not included in the Palaearctic catalogue, either (Borowski 2007), although Tsushima Island lies between Japan and South Korea, i.e. in the Palaearctic region. In 2021 the holotype of M. japonicus was found and is now held in the collection of Ehime University (EUMJ). Based on the holotype and several other specimens (including females) the species was redescribed ( Yoshitomi 2021). The author provided a detailed description of the species, colour photographs and black-and-white figures of male genital segments of M. japonicus . The detailed description leaves no doubt as to the fact that the M. japonicus is a junior synonym of M. batillus ( Lesne, 1902) , the most common representative of a genus occurring in the Mainland Southeast Asia. Full synonymy of the species along with its geographical distribution is presented below.