(Family): Well-developed tail spine present usually. Eye and spiracle on top of head. (Genus): Disc notably expanded laterally, disc width more than 1.5 times of disc length usually. (Species): Body smooth. Postermedial margin of spiracle without tentacle-like structure. No spine on tail. Tail with 3〜4 black bands.
Distribution:
Warm-temperate sea of the western Atlantic.
Remarks:
G. altavela, widely distributed in the Atlantic, has well-developed tail spine and a slender tentacle-like structure at the posteromedial margin of spiracle. (Uyeno and Miyake)