Key to species of Iphinoe from Japan, Korea and China

1. Female; uropod peduncle without long setae on inner margin. Male; carapace dorsal surface with 1 or more prominent spines ................................................................................................... 2

- Female; uropod peduncle with long setae on inner margin. Male; carapace dorsal surface without prominent spines....... 3

2. Female; carapace lower margin not serrated, except for near anterolateral corner. Male; carapace dorsal surface with 1–2 spines................................................................................... I. sagamiensis

- Female; carapace anterior half of lower margin serrated. Male; carapace dorsal surface with 2–5 prominent and some minute spines................................................................................... I. wakasaensis

3. Female; carapace dorsal surface with 4–5 teeth.................................................... I. gurjanovae

- Female; carapace dorsal surface with 13–20 teeth........................................................... 4

4. Female; carapace with longitudinal ridge running on side running from antennal notch; pereopod 1 propodus with 3 long setae on inner margin. Male; carapace anterolateral corner without teeth........................................ I. tenera

- Female; carapace without longitudinal ridge on side; pereopod 1 propodus with 4–6 long setae on inner distal region. Male; carapace anterolateral corner with teeth....................................................... I. indenticulata