体色斑紋が本種と類似するG. kolposの背鰭は体と同様に白色点をもって模様づけられ,交互に並ぶ白色帯と黒色帯を欠く(Böhlke and Böhlke, 1980)。 (上野・佐々木)
Distinctive characters:
Pectoral fin absent. Gill-opening small, subequal to eye, and located on mid-side of body. Anus slightly forward of mid-body, total length 2.1 times of preanal length. Dorsal origin on head. Mouth closes completely. Anterior nostril with tube near tip of snout; posterior nostril roundish with slightly raised rim located above the anterior margin of eye. Teeth finely serrated. Ground color of body variable from light brown to chestnut brown among the specimens; the color of head and especially of throat paler; posterior half of tail nearly black, spotted with distinct white roundish markings larger than eye; white and black bands on dorsal fin; corner of mouth and gill-opening not black.
Distribution:
Coastal waters from Gulf of Mexico to Rio Grande do Sul, Brazil.
Remarks:
The present species is similar to G. kolpos in general coloration, but the dorsal fin of the latter is marbled with white spots and lacks black and white bands (Böhlke and Böhlke, 1980). (Uyeno and Sasaki)