Key to species of Parasaccogaster

1 Nasal chamber black; vertebrae 45; anal fin rays 37; head width 12.0 % SL............................. melanomycter

- Nasal chamber not black; vertebrae 54–58; anal fin rays 49–54; head width 7.7–9.8 % SL............................ 2

2 Gill filaments on first gill arch short (1–2 times developed rakers); precaudal vertebrae 20; pectoral fin rays 12; strong ethmoi- dal spine................................................................................ rhamphidognatha

- Gill filaments on first gill arch long (4–5 times developed rakers); precaudal vertebrae 14–16; pectoral fin rays 17–19; no eth- moidal spine................................................................................... normae