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The mature spermatozoa of two Taiwan protandrous hermaphrodite Sparidae Acanthopagrus berda and Acanthopagrus australis are investigated and compared with those of other two Sparidae (Lagodon rhomboids and Archosargus probatocephus) from the Western hemisphere. Ultrastructurally the spermatozoon of these four species has a spherical, homogeneously electron-dense nucleus with an axial nuclear fossa. The midpiece contains one to four spherical mitochondria and encircles the basal body of the flagellum. The mature spermatozoa of the four species are of the primitive or ect-aquasperm form and conform to the teleostean type I spermatozoon with the flagellar axis inserts perpendicular and medial to the nuclear fossa. Variation in the depths of the nuclear fossa and mitochondria number is substantial in these four Sparidae species. This study provide useful systematic characters to the existing knowledge of comparative spermatology of Sparidae.

Transmission and scanning electron microscopy were used to investigate the ultrastructure of spermatozoa in two Sparinae species Pagrus major and Rhabdosargus sarba. Ultrastructurally, the spermatozoa of P. major and R. sarba both consist of a spherical, homogeneously electron-dense nucleus with a deep axial nuclear fossa, and an unusual notch, in the nuclear region. The midpiece contains two spherical mitochondria in R. sarba and one in P. major. The comparison of spermatozoal ultrastructure of these two species of Sparidae shows that they closely resemble one another and suggests that they are closely related. Variation in the geometry and dimensions of the mitochondrion and nucleus is substantial in these two Sparidae species. It is concluded that the spermatozoa of both species are of primitive type, and they are distinguished by several unique features which may provide useful systematic characteristics.