Scale characteristics of two fish species, Acanthopagrus bifasciatus (Forsskål, 1775) and Rhabdosargus sarba (Forsskål, 1775) from the Red Sea at Jeddah, Saudi Arabia.

The present work aimed to screening and documenting the diversity of scale characteristics of two species belonging to two different genera of the family Sparidae: Acanthopagrus bifasciatus and Rhabdosargus sarba from the Red Sea. The valid useful scale characters for systematic purposes were determined in the term of morphometry and Scanning Electron Microscopic techniques. A wide spectrum of size-free intraspecific variations between different body regions was recorded in each species in terms of morphometric indices. The scale characters included the overall form of the scales and their morphometrics, radii counts, shape of interradial tongues, the first circuli, form of interradial circuli and their denticles, the outer lateral and inner lateral circuli and the form of their denticles, granulation of the caudal field and the shape of ctenii. Moreover, the form of the lateral line canal, the relative position of their anterior and posterior openings and the cantilevered anterior extension of the canal were valid in differentiation between species.