A new species of the genus Diploderma (Reptilia, Squamata, Agamidae) from Zayü County, Xizang Autonomous Region, China

A new species of the agamid genus Diploderma Hallowell, 1861 is described from Gula Township, Zayü County, Xizang Autonomous Region (Tibet), China, based on integrated morphological and molecular evidence. Phylogenetic analyses of mitochondrial ND2 genes reveal that the new species Diploderma gulaense Cai, Yao, Wu & Guo, sp. nov . forms a well-supported clade with D. laeviventre , D. yangi , and D. slowinskii , endemic to the Nu River valley. It is sister to D. laeviventre but differs from it and other congeners by a combination of morphological characteristics: moderate body size (SVL 53.1–63.4 mm in males, 54.8–70.2 mm in females); relatively long tail (TAL/SVL 2.07–2.38 in males, 1.90–2.26 in females); tympanum concealed; ventral body scales strongly keeled; transverse gular fold present; cyan gular spot in both sexes; pale cyan dorsolateral stripes in males; and tongue pale flesh colored. The new species is currently known only from the Ranbuqu valley, a dry-warm valley along a tributary of the middle Nu River, at elevations between 2,332 and 3,300 m. Its restricted distribution and ongoing habitat degradation suggest a preliminary IUCN assessment of Vulnerable (VU). The discovery of Diploderma gulaense Cai, Yao, Wu & Guo, sp. nov . further highlights the role of river-valley systems in driving allopatric speciation within the genus and underscores the underestimated diversity of Diploderma in the Hengduan Mountains.