Rhinogobius, Gill, 1859

Chen, I-Shiung, Wang, Shen-Chih & Shao, Kwang-Tsao, 2022, A new freshwater gobiid species of Rhinogobius Gill, 1859 (Teleostei: Gobiidae) from northern Taiwan, Zootaxa 5189 (1), pp. 29-44 : 40

Diagnostic key to all nominal species of Rhinogobius species from Taiwan

1a Infraorbital papillae row a and c with transverse extension; predorsal region with large ctenoid scales; pelvic fin large and elliptical............................................................................. R. similis Gill, 1859

1b Infraorbital papillae row a and c as typically linear, longitudinal pattern; predorsal region naked or merely with small cycloid scales; pelvic fin small and rounded...................................................................... 2

2a no preopercular canal................................................................................. 3

2b preopercular canal present.............................................................................. 4

3a second dorsal fin modally I/9; anal fin modally I/8; rear edge of mouth extending merely to vertical of anterior margin of pupil in male; snout with two broad, lateral stripes (posterior one orange in male)................. R. yangminshanensis n. sp.

3b second dorsal fin modally I/8; anal fin modally I/7; rear edge of mouth extending to middle vertical of eye in male; snout with one lateral orange or brownish red curve turning vertically...................... R. rubromaculatus Lee & Chang, 1996

4a scale rows between origin of first dorsal fin and pectoral fin 6–8; abdomen median naked before anus....................................................................................... R. maculafasciatus Chen & Shao, 1996

4b scale rows between origin of first dorsal fin and pectoral fin 9–15; abdomen median with small cycloid scales before anus. 5

5a second dorsal fin and caudal fin pale..................................................................... 6

5b second dorsal fin and caudal fin with some rows of spots..................................................... 7

6a row b with 7–8 papillae; lateral body uniformly unmarked............................. R. candidianus (Regan, 1908)

6b row b with 12–13 papillae; lateral midline of trunk with 5–6 deep gray bloches...... R. nantaiensis Aonuma & Chen, 1996

7a Cheek with brownish red wavy lines................................................ R. formosanus Oshima, 1919

7b Cheek with orange or brown, blackish brown spots......................................................... 8

8a Lateral midline of trunk with vertical deep brown or grayish brown blotches; caudal fin base with a blackish brown curves. 9

8b Lateral midline of trunk in lacking conspicuous blotches; caudal fin with two well separate deep brown bars........... 10

9a pectoral fin rays 21–23; longitudinal scale rows 36–39; prepelvic area naked............. R. gigas Aonuma & Chen, 1996

9b pectoral fin rays 19–21; longitudinal scale rows 32–35; prepelvic area with small cycloid scales.......................................................................................... R. lanyuensis Chen, Miller & Fang, 1998

10a pectoral fin rays modally 18; median fin black; cheek with 100–120 very tiny black spots...................................................................................................... R. delicatus Chen & Shao, 1996

10b pectoral fin rays always 19–20; median fin pale brown; cheek with 15–30 red or brownish red small spots...................................................................................... R. henchuenensis Chen & Shao, 1996