Gobiodon

Herler, Juergen, Bogorodsky, Sergey V. & Suzuki, Toshiyuki, 2013, Four new species of coral gobies (Teleostei: Gobiidae: Gobiodon), with comments on their relationships within the genus, Zootaxa 3709 (4), pp. 301-329 : 327-328

Key to species of Gobiodon from the Red Sea

1a. Head and body all plain black; caudal-peduncle depth 14–15% SL.................................... G. at e r sp. nov.

1b. Colour not as above; caudal-peduncle depth 15–18% SL....................................................... 2

2a. Black or dark blue spot (usually retained when preserved) at upper posterior margin of operculum..................... 3

2b. No dark spot at upper corner of operculum.................................................................. 4

3a. Body depth 38–42% SL; no median groove on isthmus; yellow in life, with two blue lines through eye, and two blue lines before and behind opercular spot.................................................................. G. citrinus

3b. Body depth 42–48% SL; a median groove on isthmus, widening posteriorly; green to bluish green, with four orange-red bars on side of head dividing dorsally, and with longitudinal, vermiculate, orange-red bands dorsally on body......... G. histrio

4a. Many, slightly oblique, light blue lines on body behind pectoral-fin base, lines becoming more irregular posteriorly..................................................................................................... G. rivulatus

4b. No vertical lines on body............................................................................... 5

5a. Body deep, depth 40-44% SL; colour uniformly dark reddish brown, densely dotted with dark brown on body, nape, and pectoral-fin base; no bars or lines on the head; iris light blue....................................... G. fuscoruber sp. nov.

5b. Body slender or moderately deep, depth 28–40% SL; head with vertical red or blue bars or lines, or two or three bars through the eye.............................................................................................. 6

6a. Body brownish orange to red, with numerous, small pale blue spots; five vertical bluish bars on head and two on pectoral-fin base; base of dorsal and anal fins with a dark reddish- or black-edged pale blue band, margin of the fins often yellow................................................................................................. G. reticulatus

6b. No spots on body or irregular red spots and lines only on upper half of body (juveniles and subadults of G. irregularis ); head with vertical blue lines or red bars below the eye; base of dorsal and anal fins without band (or with a narrow bluish line in some subadults of G. bilineatus ).......................................................................... 7

7a. Uniformly reddish brown (adults) or with red spots and irregular short lines on upper half of head and body (juveniles and subadults); head with three orange-red bars below eye, indistinct in adults.......................... G. irregularis sp. nov.

7b. No spots on head and body; head with five blue lines or at least two blue lines across eye (adults of G. bilineatus )........ 8

8a. Adults and juveniles translucent greenish grey; five vertical blue lines on the head and pectoral-fin base in juveniles and adults; ovate internal bluish grey spots along vertebral column; body depth 28–36% SL; distance between anterior D1 insertion and dorsal insertion of pectoral-fin 42–50% of head length................................................ G. prolixus

8b. Adults and subadults uniformly bright orange-red or dark red, juveniles greenish; no lines on the head (adults) or five blue vertical lines on the head and pectoral-fin base (juveniles and subadults); no internal spots visible along the vertebral column; body depth 36–40% SL; distance between D1 insertion and dorsal insertion of pectoral-fin 53–71% of head length............................................................................................. G. bilineatus sp. nov.