Rhinogobius Gill, 1859

Chen, I-Shiung & Yeh, Ming-Fon, 2024, Two new freshwater gobiid species of Rhinogobius Gill, 1859 (Teleostei: Gobiidae) from Taiwan, Zootaxa 5550 (1), pp. 333-353 : 348-349

Diagnostic key of 13 nominal species of Rhinogobius Gill, 1859 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 roundedf...................................................................... 2

2a Vertebral count 27; no preopercular canal.................................................................. 3

2b Vertebral count 26; preopercular canal present.............................................................. 6

3a Second dorsal fin modally I/9; anal fin modally I/8; snout with two broad, lateral stripes (posterior one orange in male).......................................................................... R. yangminshanensis Chen et al., 2022

3b Second dorsal fin modally I/8; anal fin modally I/7; snout with one lateral orange to brownish red, brown curve turning vertically........................................................................................... 4

4a Pectoral fin rays modally 17; longitudinal scale series modally 33......................... R. baborinisanensis n. sp.

4b Pectoral fin rays modally less than 17; longitudinal scale series modally 28–29.................................... 5

5a Pectoral fin rays modally 15; predorsal scale series usually 14–15; the black blotch on first dorsal fin large and its height about 1/2 length of second dorsal spine in male............................................. R. macromaculatus n. sp.

5b Pectoral fin rays modally 16; predorsal scale series modally 11; the black blotch on first dorsal fin small and its height about 1/4 length of second dorsal spine in male................................... R. rubromaculatus Lee & Chang, 1996

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

6b Scale rows between origin of first dorsal fin and pectoral fin 9–15; abdomen median with small cycloid scales before anus..... 7

7a Second dorsal fin and caudal fin pale......................................................................... 8

7b Second dorsal fin and caudal fin with some rows of spots..................................................... 9

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

8b Row b with 12–13 papillae; lateral midline of trunk with 5–6 deep gray bloches..... R. nantaiensis Aonuma & Chen, 1996

9a Cheek with brownish red wavy lines............................................... R. formosanus Oshima, 1919

9b Cheek with orange or brown, blackish brown spots......................................................... 10

10a Lateral midline of trunk with vertical deep brown or grayish brown blotches; caudal fin base with a blackish brown curve..................................................................................................... 11

10b Lateral midline of trunk in lacking conspicuous blotches; caudal fin with two well separate deep brown bars........... 12

11a Pectoral fin rays 21–23; longitudinal scale rows 36–39; prepelvic area naked............ R. gigas Aonuma & Chen, 1996

11b Pectoral fin rays 19–21; longitudinal scale rows 32–35; prepelvic area with small cycloid scales.......................................................................................... R. lanyuensis Chen, Miller & Fang, 1998

12a Pectoral fin rays modally 18; median fin black; cheek with 100–120 very tiny black spots...................................................................................................... R. delicatus Chen & Shao, 1996

12b 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