Species placed in this group have long been associated with the genus Trimeresurus. One other species that is included in some other taxonomies is O. tonkinensis (Bourret, 1934). It is commonly called the Tonkin pit viper and is found in Vietnam and China.
^ abcdefMcDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).