Material and methods
Most specimens of fishes in the study were from the National Inland Fisheries Institute (NIFI), Kasetsart Museum
of Fisheries (KUMF), and those collected by the authors in 2009–2012. Only specimens that were not or barely
inflated were measured. Fin-ray counts and measurements were made on the left side of specimens. Measurements
were made point to point with dial calipers, and the data recorded to tenths of millimeter. Standard length, total
length, dorsal-fin base length, head length, snout length, interorbital distance, eye diameter, mouth width, and
pectoral-, dorsal-, anal- and caudal-fin ray counts were made according to Dekkers (1975). Other measurements
included internasal distance; interopercular distance; head depth and width at preorbital, postorbital and nape;
interpectoral-fin distance; prepectoral-, predorsal- and preanal-fin lengths; pectoral-, dorsal- and anal-fin base
lengths; depth and width of body at middle of base of dorsal fin; and caudal-peduncle length, depth and width.
Subunits of the head are presented as percents of head length (%HL), while head length and measurements of body