Key to males of the species of Nesotanais .

1. Plumose setae of pleopod rami only on distal margin....... N. maclaughlinae

– Plumose setae of pleopod rami on distal and outer margins ....................... 2

2. Cheliped dactylus with two strong triangular processes .............. N. lacustris

– Cheliped dactylus with three small or toothed processes and three spiniform setae........................................................................................................... 3

3. Maxilliped bases with one pair of ventrodistal setae, shorter than the maxilliped palp; cheliped flange long, with rectangular distal margin..... N. rugula

– Maxilliped bases with one pair of ventrodistal setae, longer than maxilliped palp; cheliped flange short, with rounded distal margin ............................... ..................................................................... Nesotanais ryukyuensis sp. n.