Key to preserved adult species of the timorensis group

1. Anal fin II,8, second-dorsal fin I,9................................................................................................................................ 2

- Anal fin II,9, second-dorsal fin I,10 or 11(northern Australia) ......... Apogonichthyoides opercularis (Macleay, 1878)

2. Pectoral-fin rays 14....................................................................................................................................................... 3

- Pectoral-fin rays 15–17................................................................................................................................................. 4

3. Two bars on body, one wide blotch on caudal peduncle (Mascarene Plateau)............................................................... .................................................................................................................. Apogonichthyoides gardineri (Regan, 1908)

- Two or three dark bars on body, two faint and one dark bar on caudal peduncle (E Indian to W Pacific) .................... .................................................................................................................... Apogonichthyoides umbratilis new species

4. Large darkish spot on upper opercle just below posttemporal (Coral Sea) .................................................................... ................................................................................................................ Apogonichthyoides chrysurus (Ogilby, 1889)

- No large darkish spot on upper opercle below posttemporal........................................................................................ 5

5. Broad dark cheek mark and/or dark spots on body ...................................................................................................... 6

- Narrow dark cheek mark; body uniform or with one to two faint bars on body (Indo-W. Pacific) ............................... ............................................................................................................ Apogonichthyoides timorensis (Bleeker, 1854b)

6. Broad dark cheek mark ................................................................................................................................................. 7

- No cheek mark, one dark spot per body scale (Mascarene Plateau) ........... Apogonichthyoides regani (Whitley, 1951)

7. Body with small darkish spots, no body bars; second-dorsal fin with small spots (New Caledonia) ............................ ................................................................................................................. Apogonichthyoides euspilotus (Fraser, 2006)

- Body with darkish scale stripes on body, two faint body bars; second-dorsal fin with a large dark spot (N. Australia and New Guinea) .............................................................................. Apogonichthyoides brevicaudatus (Weber, 1909)