Introduction
At least four species of Barilius Hamilton (1822) are found in Thailand (Tejavej 2010). Of these Barilius ornatus
Sauvage is the oldest name, having been described in 1883 based on two specimens provided by M. Harmand
(Sauvage 1883). Their locality was given as Menam, Siam. Although it has been presumed that “Menam” refers to
the Chao Phraya River as reported by Smith (1945) and Kaewpaitoon (1979), the word “menam” means “river” in
Thai, and it could refer to any river in Siam (Thailand) at that time; for example Mekong River was referred to as
“Me Nam Kawng” (McCarthy 1900). Even if “Menam” is the Chao Phraya River it is not known what part of this
large basin (with four main northern tributaries) these specimens are from.