Integrative taxonomy identifies a new species of Trimeresurus Lacépède, 1804 (Reptilia: Serpentes: Viperidae) from Yunnan Province, China

We collected several specimens of the subgenus <i>Viridovipera</i> in Yunnan Province, China in recent years. Based on morphological characters and phylogenetic analysis, we confirm that <i>T. yunnanensis</i> is distributed in the west of the Honghe River in Yunnan Province and the <i>Trimeresurus</i> species living along the lower reaches of the Honghe River Basin and adjacent areas is an undescribed taxon. The new species <i>Trimeresurus hongheensis</i><b> sp. nov. </b>can be distinguished from all known congeners by the pairwise genetic divergence in the mitochondrial cytochrome-<i>b</i> (p-distance ≥ 5.0%) and 16S rRNA gene fragment (p-distance ≥ 0.5%), and morphologically by the combination of the following characters: (1) hemipenes short and strongly spinose, with deep bifurcation; (2) a white postocular stripe bordered above and below by red or only a white postocular stripe present in males; postocular stripe white or absent in females; (3) the ventrolateral stripe is red (below) and white (above) in males and white in females; (4) iris brick red or sepia in males; iris yellow or rusty-red in females; (5) VEN 150–165 in males and 157–165 in females; SC 61–76 in males and 56–61 in females; (6) dorsal tail mostly rusty red; (7) 9–12 cephalic scales; (8) MSR 19 or 21; (9) first supralabial completely separated from the nasal scale.