Key to the species of Saccogaster

1 Scales present on body................................................................................ 2

- Scales absent from body................................................................................ 6

2 Opercular spine free, with 3 prongs; pectoral fin rays 22; dorsal fin rays 92.................................. hawaii

- Opercular spine free or hidden, with single prong; pectoral fin rays 16–19; dorsal fin rays 80–88....................... 3

3 Gill filaments on anterior arch short (1/3–1/5 times length of developed rakers)................................... 4

- Gill filaments on anterior arch about equal to or longer than developed gill rakers.................................. 5

4 Scales present on predorsal; 12–13 precaudal vertebrae; no brown stripe on head; numerous neuromasts...... nikoliviae n.sp.

- Scales absent on predorsal; 21 precaudal vertebrae; broken brown stripe on sides of head; no neuromasts....... brayae n.sp.

5 Gill filaments on anterior arch distinctly longer than developed gill rakers; opercular spine free; palatines with several tooth rows; dorsal fin rays 83–85; posterior infraorbital pores 2, posterior supraorbital pore 1, posterior mandibular pore 1....... maculata

- Gill filaments on anterior arch 0.5–1 times length of developed gill rakers; opercular spine hidden; palatines with a single tooth row; dorsal fin rays 86–88; no posterior infraorbital pores, no posterior supraorbital pore, no posterior mandibular pore..................................................................................................... staigeri

6 Developed gill rakers on anterior arch 5–6; pectoral fin rays 14; numerous neuromasts........................... parva

- Developed gill rakers on anterior arch 3; pectoral fin rays 19–22; 0–3 neuromasts................................... 7

7 Skin thin; opercular spine free; spines on frontal plate visible, bony ridges above eyes; distance from base of pelvic fins to ori- gin of anal fin 46.0% SL; vomer and premaxillaries with fangs; no posterior mandibular pore.................... horrida

- Skin thick; opercular spine hidden; spines on frontal plate sub-dermal, no bony ridge above eyes; distance from base of pelvic fins to origin of anal fin 32.0–39.0 % SL; no fangs, dentition granular; large posterior mandibular pore......... tuberculata