Elasmopus, Costa, 1853

Yoshimura, Hiro & Tomikawa, Ko, 2025, A new species of the genus Elasmopus (Crustacea: Amphipoda: Maeridae), from Honshu, Japan, Zootaxa 5653 (2), pp. 286-296 : 295-296

Key to the species of Elasmopus found in Japan

1 Male gnathopod 2 propodus palmar margin with a few clusters of slender setae; pereopods 6–7 basis with long setae on posterior margin; telson longer than wide............................................................ E. nkjaf

- Male gnathopod 2 propodus palmar margin with densely slender setae; pereopods 6–7 basis without long setae on posterior margins; telson shorter than wide........................................................................ 2

2 Urosomite 1 with triangular process dorsally...................................................... E. japonicus

- Urosomite 1 dorsally smooth............................................................................ 3

3 Male gnathopod 2 propodus mid-palmer margin with a long ridge; pereopod 7 merus to propodus with slender setae on posterior margins................................................................................... E. mukuinu

- Male gnathopod 2 propodus mid-palmer margin with a well-developed process; pereopod 7 merus to propodus without slender setae on posterior margins.............................................................. E. projectus sp. nov.