Abstract: The conodont Rabeignathus bucaranumgus fauna is for first time found at the base of the Tulonggongba Formation at the Tuotala section in the Doima district, R.utog County, Ngari, Tibet. It is mainly composed of Rabeignathus bucaramangus, Sweetognathus whitei, Sweetognathus ironatus and Mesogondolella cf. bissilli, indicating a mid-late Artinskian-early Kungurian age. Before, this fauna was only discovered in Utah and Kansas of the United States, Bucaramanga of Colombia, the southeastern part of Pamir and the Baoshan area of western Yunnan, China. This conodont fauna occurs in the Karakorum stratigraphic area north of Bangong Co and south of Lungmu Co across the northern boundary of the Bangong Co-Nu- jiang fault belt and is considered to be a shallow-water facies type characteristic of the neritic region on the northern margin of Gondwana. Therefore, it is inferred that the Bangong Co-Nujiang suture zone is likely not to be the northern boundary of Gondwana.