Nebria (Falcinebria) reflexa Bates (Carabidae), a Japanese endemic flightless ground beetle, is geographically polytypic and was thought to be composed of four subspecies (including nominotypical subspecies). Populations from Honshû recognized as three subspecies were taxonomically revised based primarily on the shape of the endophallus, a membranous inner sac everted from the aedeagus. Three known taxa, Nebria reflexa, Nebria niohozana Bates, and Nebria uenoi Nakane, are redefined based on endophallus morphology, and the latter two are described as distinct species rather than subspecies of N. reflexa. Seven new species are described: N. sagittata sp. nov., N. iidesana sp. nov., N. furcata sp. nov., N. pisciformis sp. nov., N. kuragadakensis sp. nov., N. dichotoma sp. nov., and N. chugokuensis sp. nov. Comparative morphology, primarily of the endophallus, indicated that N. furcata, N. pisciformis, N. kuragadakensis, and N. uenoi form basal lineages, and the remaining six species form a clade in which N. niohozana and N. dichotoma are sister taxa. Species phylogeny and known distributions suggest that the initial diversification of these species occurred in the western Chûbu and eastern Kinki regions of Japan.
Keywords: Biogeography; Japan; cryptic species; endophallus; ground beetle; male genitalia; phylogeny; taxonomy.
Kôji Sasakawa.