Much variation occurs in morphology and colouration among individuals of Japanese Mnais spp. It has been noted that 2 groups of Mnais often cohabit a stream in western Japan. There is, however, no clear morphological difference in 6 appendages and penis between the 2 groups, and this makes it difficult to determine their taxonomic status. In this study, to clarify the relationships between the sympatric species on both small (along a stream) and large (across Japan) geographic scales, sequences of the internal transcribed spacers 1 and 2 (ITS1 and 2) of nuclear ribosoraal DNA are compared. Base substitutions occurred at 4 sites of223 bps of the ITS 1 region, and by their combinations, the four sequence types could be distinguished among a total of 800 individuals. In the ITS2 region (total 411 bps including 5.8S rRNA region), all examined individuals had the same sequence. The geographical distribution of each ITS 1 sequence type and morphological data of wings and a pterostigma suggest that Japanese Mnais includes 2 distinct spp., M. strigata Selys, 1853 and M. costalis Selys, 1869. Their distribution ranges overlap widely in western Japan, where M. strigata is usually found at smaller and upper streams than M. costalis.


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Societas Internationalis Odonatologica

F. Hayashi, S. Dobata, & R. Futahashi. (2004). Macro- and microscale distribution patterns of two closely related Japanese Mnais species inferred from nuclear ribosomal DNA, its sequences and morphology (Zygoptera: Calopterygidae). Odonatologica, 33(4), 399–412.