A New Species of the <i>Gloydius strauchi</i> Complex (Crotalinae: Viperidae: Serpentes) from Qinghai, Sichuan, and Gansu, China

The Hengduanshan Mountains have long been recognized as one of the evolutionary radiation centers of the genus Gloydius . Here we describe a new species of the Gloydius strauchi complex, Gloydius angusticeps sp. nov. Shi, Yang, Huang, Orlov et Li, 2018, which has been discovered in the adjacent areas of Sichuan, Qinghai, and Gansu Province, at the elevation of 3150 – 3653 m near the Yellow River. The new species is different from congeneric species by the following characteristics: (i) long and narrow head; (ii) grayish brown body coloration (few variations); (iii) 4 to 6 rows of discrete dark brown spots (or Ч-shaped patterns on the back); (iv) a pair of round spots on the parietal scales; (v) a pair of arched stripes on the occiput; (vi) up to 21 rows mid-body dorsal scales. This study preliminary clarified the distribution pattern of the Gloydius strauchi complex in Qinghai and Sichuan Province. The discovery of this new species verifies the importance of the Hengduanshan Mountains as a biodiversity hotspot.