This study describes a novel species of Diploderma (Squamata, Agamidae) from the lower valley of the Dadu River of the Sichuan Province of Western China based on its distinct morphological features and molecular evidence. D. daduense sp. nov. can be distinguished from its congeners by its tympanum concealed; head mainly green-yellow, supplemented by black; skin folds under the nuchal and dorsal crest obviously present in adult males only, its vertebral crest discontinuous between nuchal and dorsal sections with a distinct gap; transverse gular fold present but not obvious in some individuals; gular spot absent in both sexes; dorsolateral stripes green-yellow anteriorly, cyan in the center and blurry off-white posteriorly in adult males, the upper edge of dorsolateral stripes strongly jagged in adult males; no radial stripes around the eyes; inner-lip coloration smoky-white, and the coloration of the tongue and oral cavity as a light-flesh color in life; bright green-yellow transverse stripes on dorsal body in males; black patches are evenly distributed along the vertebral line between the dorsolateral stripes from the neck to the base of the tail in males; beech-brown or gray-brown line along the vertebral line with heart-shaped or diamond-shaped black patches on the dorsal body in females; and supratemporals fewer than four on at least one side. The phylogenetic tree based on mitochondrial ND2 sequences indicates that D. daduense sp. nov. forms an independent clade with strong support 1/100 in ML bootstrap/Bayesian posterior probability and is the sister group to D. splendidum. At the inter-species level, the p-distance is at least 6.95%, further confirming that an independent species had been identified. Our work raises the number of species within the genus Diploderma to 47.

A new species of the genus Diploderma is described from the upper Dadu River Valley in the Hengduan mountains of Sichuan Province, China. Phylogenetic analyses based on the mitochondrial ND2 gene revealed that the new species, Diploderma bifluvialesp. nov., forms a distinct lineage within the Diploderma flaviceps group with an uncorrected genetic distance of ≥3.88%. Morphologically, the new species differs from its congeners by a combination of characters, including a shorter snout-vent length (SVL 62.51–72.55 mm), a shorter tail (TAL/SVL ratio 1.37–1.56), concealed tympanum, absence of a gular spot, and lemon-chiffon dorsolateral stripes with serrated edges in males. Additionally, Diploderma bifluvialesp. nov. exhibits unique coloration traits such as a wheat-colored tongue and the fourth toe with claw reaching either the tympanum or the area between shoulder and tympanum when hind limbs adpressed forward. The species inhabits semi-arid shrublands in warm-dry valleys at elevations of 2,187–2,525 m – a habitat that is distinct from those of its closest relatives. This discovery highlights the understudied biodiversity of the upper Dadu River. Diploderma bifluvialesp. nov. represents the 49^th species of the genus and expands our understanding of morphological and ecological diversity within the D. flaviceps group.

The genus Trimeresurus Lacépède comprises over 57 species, with recent taxonomic revisions recognizing six subgenera. Despite extensive research, many regions in China remain understudied, particularly the biodiversity-rich West China Rain Zone. This study reports a new pitviper species from western Sichuan Province, China, based on comprehensive morphological and molecular analyses. Specimens collected from the West China Rain Zone were examined using detailed morphological comparisons and phylogenetic analyses of three mitochondrial genes ( 16S , cytb , and ND4 ). The results show that this population, together with T. loong , forms a distinct monophyletic clade within the subgenus Viridovipera Malhotra & Thorpe, with uncorrected genetic distances to its closest relatives exceeding 6.50% ( cytb ) and 5.77% ( ND4 ). Diagnostic morphological differences, including smooth cephalic scales, a postocular streak extending beyond the 2 ^nd supralabial in males, dorsal scale rows of 21–21–15, and a grass-green body color lacking bands or markings, further support its taxonomic distinctness. We propose the new species Trimeresurus lii sp. nov ., which represents the second species of Viridovipera in Sichuan Province and the 58 ^th species of Trimeresurus worldwide, and contributes to understanding biodiversity in the Giant Panda National Park region. This discovery highlights the importance of continued field surveys in biodiversity hotspots for documenting and conserving unique faunal assemblages.

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.