This species is distinguished from its Sundaic congeners except G. platypogon in having a convex (vs. straight) dorsoposterior margin of the adipose fin; differs from G. platypogon in having a longer pectoral-fin spine 19.4-22.9% SL (vs. 13.6-17.9) and a longer caudal fin 26.9-30.7% SL (vs. 20.1-27.0). It is further distinguished from its Sundaic congeners by the following unique characters: eye diameter 7-11% HL; head width 18.8-20.4% SL; no anteromedial striae in thoracic adhesive apparatus; predorsal length 36.4-41.3% SL; dorsal-fin spine length 16.0-20.1% SL; margin of dorsal fin concave; dorsal-to-adipose distance 18.4-22.5% SL; body depth at anus 14.0-15.8% SL; adipose-fin base length 13.6-17.2% SL; post-adipose distance 15.2-16.7% SL; caudal peduncle depth 7.7-8.8% SL; premaxillary toothband partially exposed when mouth is closed; uniformly dark body with neither contrasting markings nor prominent pale midlateral stripe (Ref. 128699).