Name from Latin 'labrum' for lip, rim or edge; referring to the big lips of the fishes of the genus (from Ovid and Pliny according to Petrus Artedi).
Etymology of specific name :
Name from the Greek makros for long, and feminine noun oura for tail, referring to the elongate tail depicted in a pencil drawing of this species on which the original description was based (Ref. 75973).