We describe a unique new species and genus of agamid lizard from the karstic massifs of Khammouan Province, central Laos. Laodracon carsticola Gen. et sp. nov. is an elusive medium-sized lizard (maximum snout-vent length 101 mm) specifically adapted to life on limestone rocks and pinnacles. To assess the phylogenetic position of the new genus amongst other agamids, we generated DNA sequences from two mitochondrial gene fragments (16S rRNA and ND2) and three nuclear loci ( BDNF, RAG1 and c-mos), with a final alignment comprising 7 418 base pairs for 64 agamid species. Phylogenetic analyses unambiguously place the new genus in the mainland Asia subfamily Draconinae, where it forms a clade sister to the genus Diploderma from East Asia and the northern part of Southeast Asia. Morphologically, the new genus is distinguished from all other genera in Draconinae by possessing a notably swollen tail base with enlarged scales on its dorsal and ventral surfaces. Our work provides further evidence that limestone regions of Indochina represent unique "arks of biodiversity" and harbor numerous relict lineages. To date, Laodracon carsticola Gen. et sp. nov. is known from only two adult male specimens and its distribution seems to be restricted to a narrow limestone massif on the border of Khammouan and Bolikhamxai provinces of Laos. Additional studies are required to understand its life history, distribution, and conservation status.
依据形态和DNA多分子片段数据，该文在老挝甘蒙省喀斯特山丘生境中发现并描述鬣蜥科1新属、新种，即老挝岩龙蜥 Laodracon carsticola Gen. et sp. nov.。老挝岩龙蜥体型中等（最大头体长101 mm），仅见于喀斯特岩峰地形中。通过整合已有64个鬣蜥科物种的线粒体（ 16S和 ND2）和核基因片段（ BDNF、RAG1和 c-mos）共7418 bp，构建了鬣蜥科的系统演化关系，结果显示老挝龙蜥属Laodracon隶属于飞蜥亚科，与主要分布于中国的龙蜥属 Diploderma构成姐妹群。形态上，老挝蜥属物种的尾基部明显膨大，且其表面具有特化、不规则排列的大鳞，可区别于飞蜥亚科所有已知属。研究进一步证实，中南半岛的喀斯特地貌区域拥有丰富的生物多样性，包括一些独特的孑遗类群。目前，老挝岩龙蜥已知仅分布于老挝甘蒙省和波里坎赛省交界区域的喀斯特山地中，分布极其狭窄，且仅已知2号标本，亟需研究补充完善该种的自然生活史、分布和受胁等级等数据。.
Keywords: Biodiversity; Endemism; Indochina; Karstic landscape; Laodracon carsticola; Phylogeny; Southeast Asia; Taxonomy.