Lateral (dorsolateral) heads of the alpine pitvipers (Gloydius) distributed in Sichuan and Tibet (not to scales) A G. lateralis sp. nov., CIB 119377 (JZ02), female, from Jiuzhaigou National Nature Reserve, Sichuan B G. swild, IVPP OV 2725, female, from Heishui, Sichuan C G. angusticeps, IVPP OV 2634, male, from Zoige, Sichuan D G. liupanensis, male, from Longnan, Gansu E G. qinlingensis, male, from Ningshaan, Shaanxi F G. strauchi, SYNU1508G4, male, from Litang, Sichuan G G. lipipengi, IVPP OV 2720, male, from Zayu, Tibet H G. rubromaculatus, male, from Yushu, Qinghai (not included in this study) I G. huangi, CIB 533422012, male, from Hola, Mangkang. Copyright: Sheng-Chao Shi (A, I), Jing-Song Shi (B, C, E, F, G, H), Zu-Yao Xia (D).