Key to the species of Metatanais (females)

1. With pleopods................................................. M. progenitor [New Zealand: Kermadec Islands]

- Without pleopods..................................................................................... 2

2. Cheliped fixed finger with a strongly developed, chisel-like, spiniform seta near the sub-distal inner margin (Fig. 7 A)......................................................................... M. spinipropodus sp. nov. [Hawaii: O'ahu]

- Cheliped fixed finger without a strongly developed, chisel-like, spiniform seta near the sub-distal inner margin (Fig. 7 B −C)..................................................................................................... 3

3. Antennal article-2 with small spiniform seta on distodorsal margin (Fig. 7 D)................. M. bipunctatus [Australia]

- Antennal article-2 without small spiniform seta on distodorsal margin (Fig. 7 E).................. M. cylindricus [Japan]