Masaaki Nishikawa

Loss of flight promotes beetle diversification

The evolution of flight is a key innovation that may enable the extreme diversification of insects. Nonetheless, many species-rich, winged insect groups contain flightless lineages. The loss of flight may promote allopatric differentiation due to limited dispersal power and may result in a high speciation rate in the flightless lineage. Here we show that loss of flight accelerates allopatric speciation using carrion beetles (Coleoptera: Silphidae). We demonstrate that flightless species retain higher genetic differentiation among populations and comprise a higher number of genetically distinct lineages than flight-capable species, and that the speciation rate with the flightless state is twice that with the flight-capable state. Moreover, a meta-analysis of 51 beetle species from 15 families reveals higher genetic differentiation among populations in flightless compared with flight-capable species. In beetles, which represent almost one-fourth of all described species, repeated evolution of flightlessness may have contributed to their steady diversification since the Mesozoic era.

Revision of the genus Ptomaphagus Hellwig (Coleoptera, Leiodidae, Cholevinae) from Taiwan Island

Abstract Ptomaphagus (s. str.) chenggongi sp. n. and Ptomaphagus (s. str.) tingtingae sp. n. (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini) are described from Taiwan Island. In addition, a new subjective synonym is proposed, Ptomaphagus (s. str.) yasutoshii Nishikawa, 1993 = Ptomaphagus (s. str.) smetanai Perreau, 1996, syn. n. Relevant morphological characters of the examined Ptomaphagus species are illustrated with colour plates, and their known distributions are mapped.

Revision of the genus Ptomaphagus Hellwig (Coleoptera, Leiodidae, Cholevinae) from Japan

Abstract After examining Japanese material of Ptomaphagus Hellwig from various collections, a new species is described, Ptomaphagus (s. str.) piccoloi sp. n., and a new subjective synonym proposed, Ptomaphagus (s. str.) kuntzeni Sokolowski, 1957 = Ptomaphagus (s. str.) amamianus Nakane, 1963, syn. n., in this paper. Relevant morphological characters of examined species of Ptomaphagus are illustrated with colour plates, and known distributions are mapped.

Revision of the genus Ptomaphagus Hellwig (Coleoptera, Leiodidae, Cholevinae) from the Russian Far East and the Korean Peninsula

Abstract The conundrum of Ptomaphagus (s. str.) sibiricus Jeannel, 1934 (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini) is solved, and it is redescribed and newly recorded in South Korea. A new species is also described from the Russian Far East: Ptomaphagus (s. str.) hayashii sp. n. Relevant morphological characters of the concerned species are illustrated with colour plates, and their known distributions are mapped.

Revision of the genus Ptomaphagus Hellwig from eastern Asia (Coleoptera, Leiodidae, Cholevinae)

Abstract The species belonging to the genus Ptomaphagus Hellwig, 1795 (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini) from eastern Asia are assigned to three species groups. Group yasutoshii has a single species: P. (s. str.) yasutoshii Nishikawa, 1993 from Taiwan, China. Group nepalensis with three species: P. (s. str.) nepalensis Perreau, 1988 from Nepal and P. (s. str.) masumotoi Nishikawa, 2011 from Thailand are redescribed, and P. (s. str.) piccoloi Wang, Růžička, Nishikawa, Perreau & Hayashi, 2016 is recorded for the first time from China (Zhejiang). Group sibiricus with seven species, including two newly described Chinese ones P. (s. str.) funiu sp. n. from Henan, and P. (s. str.) haba sp. n. from Yunnan, and five known species: P. (s. str.) chenggongi Wang, Nishikawa, Perreau, Růžička & Hayashi, 2016, P. (s. str.) hayashii Wang, Růžička, Perreau, Nishikawa & Park, 2016, P. (s. str.) kuntzeni Sokolowski, 1957 (distribution records from Myanmar excluded), P. (s. str.) sibiricus Jeannel, 1934 and P. (s. str.) tingtingtae Wang, Nishikawa, Perreau, Růžička & Hayashi, 2016. Specimens of other undescribed species of the group sibiricus are also recorded, revealing a high diversity of this genus in eastern Asia, especially in central and north Sichuan, China, which essentially remains to be investigated. Relevant morphological characters of the examined species are illustrated with colour plates, and their known distributions are mapped. A key to species of Ptomaphagus from eastern Asia is provided.