Postodius, Hirayama, 1983, Hirayama, 1983

Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, Zootaxa 5067 (4), pp. 485-516 : 500

Key to the species of the genus in the world [revised from Ariyama (2011)].

1. Gnathopod 2 propodus wide (width:>0.65 times length in male,>0.7 times length in female)........ P. sanguineus sp. nov.

- Gnathopod 2 propodus narrow (width: <0.65 times length in male, <0.7 times length in female)....................... 2

2. Anterior margin of basis of pereopod 3 without plumose setae in male and with 0–5 plumose setae in female........................................................................................ P. imperfectus Hirayama, 1983

– Anterior margin of basis of pereopod 3 with 1–12 plumose setae in male and with many (>11) plumose setae in female.... 3

3. Basis of pereopod 7 relatively broad, roundish.............................................................. 4

– Basis of pereopod 7 relatively narrow, a little longer than wide................................................. 5

4. Merus of gnathopod 2 slightly projected posterodistally...................................... P. albifacies sp. nov.

– Merus of gnathopod 2 distinctly projected posterodistally................................. P. striatus Ariyama, 2011

5. Posterior margin of basis of pereopod 7 expanded at 0.65 of length.......................... P. igneus Ariyama, 2011

– Posterior margin of basis of pereopod 7 expanded at 0.75–0.8 of length...................... P. ornatus Ariyama, 2011