Key to species of Synaphobranchus found in Taiwan

1A. Most of head, nape and abdomen naked; origin of dorsal fin slightly before to about opposite to anus (some slightly behind the anus); predorsal vertebrae 21–33; precaudal vertebrae 50–56................................... S. oligolepis sp. nov.

1B. Scales cover entire body, except for fins and anterior portion of head; origin of dorsal fin far behind the anus; predorsal vertebrae 36–49; precaudal vertebrae 60–69.................................................................... 2

2A. Scales on body oval to slightly elongate; total vertebrae 145–147; predorsal length 31–36% TL.................. S. kaupii

2B. Scales on body rounded or irregular, never elongate; total vertebrae 126–132; predorsal length more than 38% TL......... 3

3A. Scales small, about 20 rows between dorsal fin and lateral line; predorsal vertebrae 42–43; predorsal length 38–40% TL............................................................................................. S. brevidorsalis

3 B. Scales large, about 10 rows between dorsal fin and lateral line; predorsal vertebrae 48–49; predorsal length 43–44% TL.............................................. S. cf. oregoni [data taken from 3 specimens collected from the Philippines]