A new species of Dwarf Japalura sensu lato (Reptilia: Squamata: Agamidae) from the upper Mekong River in Eastern Tibet, China, with notes on morphological variation, distribution, and conservation of two congeners along the same river

Despite being recognized as ecologically and biogeographically important, the biodiversity of the Hengduan Mountain Region, particularly along the upper Mekong River, remains poorly understood. Here we describe a new species of Mountain Dragon of the genus Japalura sensu lato Gray, 1853 from the headwater region of the Mekong River in Chamdo, Tibet Autonomous Region, China. The species is recognized as a member of the Japalura flaviceps Barbour & Dunn 1919 complex, and it can be distinguished readily from all congeners by a suite of morphological characteristics, including its dwarf appearance (small body size and disproportionally short tails and short hind limbs), smooth or weakly keeled ventral scales, feebly developed vertebral crests in males, and by the absence of distinct gular spots in males and females. In addition to the description of the new species, we also report morphological variations and range extensions of two recently described congeners along the same river, namely J. iadina and J. vela. We discuss the distribution patterns of the genus in the Hengduan Mountain Region and the urgent conservation priorities for protecting Japalura species along the Mekong River. According to our best available data, we provided IUCN assessments of the three species and propose to list them as nationally protected under the Chinese Wildlife Protection Act.