Morphometric methods mostly follow Gill (1998) for easier species comparison within the genus. The length of the specimens is presented as standard length + caudal-fin length. Standard length (SL) is measured from the median anterior point of the upper lip to the base of the caudal fin (posterior end of the hypural plate). Morphometric data presented are given as percentages of SL. Measurements: head length is taken from the median anterior point of the snout tip to the fleshy edge of the operculum; eye diameter is the horizontal (greatest) fleshy diameter; head width