Identification key for the species of Gonyosoma

Based on a review of the literature and our examined material, we propose the following provisional identification key to the species of the genus Gonyosoma:

1a. Nasal appendage present............................................................................... 2

1b. Nasal appendage absent................................................................................ 3

2a. Two loreals; black orbital stripe absent in adults; endemic to Hainan Island (China)........................................................................................................................... G. hainanense

2b. One loreal; black orbital stripe present in adults.................................................. G. boulengeri

3a. Loreal shield present.................................................................... .. frenatum complex

3b. Loreal shield absent................................................................................... 4

4a. 23–27 midbody dorsal scale rows........................................................................ 5

4b. 19 midbody dorsal scale rows........................................................................... 6

5a. Snout more obtuse and relatively short; endemic to Sulawesi Island (Indonesia)............................ G. jansenii

5b. Snout subacuminate, elongate, obliquely truncate, and projecting........................... G. oxycephalum complex

6a. Dorsal surface dark, speckled with turquoise, with conspicuous yellow-orange bands on the posterior half of the body............................................................................................. G. margaritatum

6b. Dorsal surface uniformly bright green.................................................................... 7

7a. Cloacal plate divided; hemipenis long, weakly spinous, extending to the 13th subcaudal................... G. coeruleum

7b. Cloacal plate undivided; hemipenis short, spinous, extending to the 5th–8th subcaudal.............................. 8

8a. Upper dorsal rows smooth or slightly feebly keeled; total number of ventrals + subcaudals <310 in males; distribution in northeast India, Bhutan, northern and northwestern Myanmar, possibly eastern Nepal ...................... G. prasinum

8b. Upper dorsal rows feebly keeled; total number of ventrals + subcaudals ≥ 310 in males; distribution in central and southern Vietnam as well as central and southern Laos ................................................ G. iadinum sp. nov.