In scutellation there are 2-3 supralabials that contact the eye, with typically two in G. oxycephalum, and three in G. jansenii.

The loreal scale is thin and elongate, and appears stretched between the preocular and the nasal.

Other diagnostic features is an elongate left rudimentary lung (70–141 mm), and a distinct hemipenes structure.

The inflation of the body exposes the black and white diagonal bands of the interstitial skin, which is particularly distinct in G. oxycephalum (Schulz 1996).

[2] Nota bene: A binomial authority in parentheses indicates that the species was originally described in a genus other than Gonyosoma.