Early Devonian rugose coral Xystriphylloides in South China is restudied from the perspective of its taxonomic definition, biostratigraphy, paleoecology, and implication for the Yujiang Event. The diagnostic characters of the genus are clarified and its taxonomic position is also revised. In particular the septa of Xystriphylloides are shown to be fibrous rather than trabeculate. Xystriphylloides distinctus Yu n. sp. is described. Species of Xystriphylloides are widely distributed in South China and North Vietnam, so they are useful for regional biostratigraphic correlation and regional geological mapping. As an important biostrome builder, Xystriphylloides became extinct below the base of the nothoperbonus Conodont Zone, so it can be considered as one of the important pieces of evidence for recognizing the first episode of the Early Devonian Emsian Yujiang Event, which is also significant for studying paleoecology and event stratigraphy. (C) 2017 Elsevier Ireland Ltd Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. Published by Elsevier B.V. All rights reserved.