Study On Species Diversity Of Genus Laudakia Gray, 1845 In Xizang Autonomous Region

The genus Laudakia Gray, 1845 within the family Agamidae Gray, 1827 is a highly diverse genus embracing more than 20 agama lizards. Tibet host four Laudkia species: L. sacra, L. wui, L. tuberculata, L. papenfussi. As one of the most common reptiles on Qinghai-Tibet Plateau, they far from well studied. Whether there is place unknown where rock agamas exist. L. papenfussi was a new species described by Ermi Zhao in 1998 based on the sole male specimen. Though 15 years gone, there is still no female specimen of L. papenfussi. Concerning L. sacra is the most widely distributed species among these four rock agamas with a huge number of wild population, there may be some sort of cryptic species under it. These information is important but remains unknown and ignored. After a thorough field work, we got a better understanding of the distribution of these four rock agamas. L. sacra occupies the upper and midstream reaches of the Yarlung Zangbo Jiang from Xigazê to Nyingchi while L. wui is located in downstream areas. Laudakia papenfussi distributed only in its type locality Zanda, Ngari and L. tuberculata occurs in Gyirong, Shigatse on the south slope of the Himalayas. In Zanda, we sampled a female L. papenfussi. After carefully examination of this female specimen, we re-described this this species based on its original description. During field work toward L. sacra, we morphologically compared specimens from different areas and figured out a special population from east Nang. They are distinguished from its L. sacra by the following combination of characters: Superciliary ridge less developed; relatively uniform brown spots on black ground dorsally; no big light yellow spots on the back or limbs; Number of scales around mid-body more than 180; Chest and belly with black or darkish. Here, we fully described this distinct group in L. sacra. For a deeper insight into morphological difference between these four species, we carried out principal component analysis using 34 morphological characters. It turned out that these four rock agamas still can be distinguished using body measurements and pholidosis despite the coloration of them. But it was unable to distinguish the west Nang population fromthe east Nang population of L. Sacra. Finally, using co1 and nd2 of these four species combined with data from Gen Bank, we conducted a phylogenetic analysis toward the whole genus. We found that Laudakia stellio from the Middle East rooted at the base of the tree. Matriline two was comprised of L. caucasia(Eichwald, 1831), L. lehmanni(Nikolsky, 1896), L. stoliczkana(Blanford, 1875) and L. microlepis(Blanford, 1874). Third matriline hosted the four Tibetan rock agamas plus L. nupta. Laudakia papenfussi and L. tuberculata, which occur on the south slope of the Himalayas, clustered together forming the Himalaya group. With a distribution along Yarlung Zangbo Jiang(Brahmaputra River), L. sacra and L. wui formed Yarlung Zangbo group. This wok supplemented the fundamental biological information of Laudakia species in Tibet and obtained an preliminary knowledge of species diversity of them. We also solved the evolution relationship between these four species and got an insight into the phylogenetic position of them in genus Laudakia. This will be of great importance for taxonomy and evolution studies toward this genus.