Key to species of Chaunax in Taiwan and adjacent waters

1A. Illicial trough deep, concave and black; illicium very short, housed within illicial trough (Figs. 2A‒B)............................................................................................. ( C. pictus group) C. penicillatus

1B. Illicial trough shallow, of same color as body; illicium stout to slender (Figs. 2C‒F)................................ 2

2A. No cirri on dorsal surface of head or above eyes; usually 1 or 3 pairs of spinules flanking lateral-line neuromasts (Figs. 3A–C); cirri along body margin flap-like (Fig. 4A) or filamentous........................................ 3 ( C. abei group)

2B. Cirri present on dorsal surface of head and above eyes; 3‒8 pairs of spinules flanking lateral-line neuromasts (Figs. 3D–E); cirri along body margin filamentous (Figs. 4B‒C)..............................................6 ( C. fimbriatus group)

3A. Mouth cavity, gill chamber and gill rakers grayish to blackish................................. C. albatrossae sp. nov.

3B. Mouth cavity, gill chamber and gill rakers pale or, rarely, grayish in small areas.................................... 4

4A. Coloration uniformly pink when fresh, without any discrete pattern, sometimes with deep red blotches; esca with pink or whitish cirri; dermal spinules slender and curved....................................................... C. apus

4B. Dorsal surface spotted; esca with brown, green or gray cirri; dermal spinules stout and straight........................ 5

5A. Spinules on dorsal surface all simple; dorsal surface of body densely covered with small spots.............. C. breviradius

5B. Spinules on dorsal surface both bifurcate and simple; large green spots encircled by yellow or large yellow spots on dorsal surface of body.................................................................................. C. abei

6A. Two large white patches on dorsal surface, one associated with underlying third dorsal-fin spine and one before dorsal-fin origin; filaments on body usually highly branched.................................................. C. fimbriatus

6B. No large white patches on dorsal surface; filaments on body surface usually simple................................. 7

7A. Body uniformly red when fresh; esca pink; entire fish turning creamy-white when preserved; BI 29–33; GH 10–11........................................................................................... C. erythraeus sp. nov.

7B. Irregular greenish or orange-red patterns on dorsal surface when fresh; esca green; gray to dark brown blotches and/or reticulates pattern on dorsal surface and esca gray to brown when preserved; BI 32–37; GH 11–13.............................. 8

8A. Very fine greenish-yellow patches on dorsal surface when fresh, these turning brown and forming very fine, pale, reticulated pattern when preserved....................................................................... .. C. umbrinus

8B. Large and irregular green reticulate patterns or yellow patches on dorsal surface when fresh, changing into dark brown reticulate patterns or fading when preserved........................................................................ 9

9A. Mouth cavity pale gray, not especially dark; bright white dots or patches on head and dorsal-fin origin when fresh; irregular green reticulate pattern on dorsal surface when fresh, changing to dark gray blotches with pale reticulate pattern when preserved. C. viridiretis sp. nov.

9B. Mouth cavity dark gray posteriorly; no bright white dots on head or dorsal-fin origin when fresh; dorsal surface with irregular yellow patches when fresh, but patches fading after preservation, forming pale blotches with light brown reticulate patterns...................................................................................... C. obscurus sp. nov.