The complex of Trimeresurus (Popeia) popeiorum Smith was revised by Vogel et al. (2004). On the basis of univariate and multivariate analyses, six clusters of populations morphologically diagnosable were recognized. Five of these clusters were considered to be distinct species at the specific level following the Biological Species Concept (BSC) and the Phylogenetic Species Concept (PS C), namely Trimeresurus (Popeia) popeiorum Smith, 1937, barati Regenass & Kramer, 1981, sabahi Regenass & Kramer, 1981, nebularis David, Vogel & Pauwels, 2004 and fucatus Vogel, David & Pauwels, 2004. A population from northern Sumatra with 21 dorsal scale rows constituted the sixth cluster but could not be assigned to any species by Vogel et al. (2004). Subsequently, Grismer et al. (2006) described Popeia buniana from Pulau Tioman. The reasons why we refer all these species to the subgenus Popeia Malhotra & Thorpe, 2004 are explained in the Discussion.