Spermatogenesis in the black porgy, Acanthopagrus schlegeli (teleostei: Perciformes: Sparidae)

Abstract

The ultrastructure of spermatogenesis and of the spermatozoon of Acanthopagrus schlegeli (Sparidae) are described. The testis is of the unrestricted type. Germ cells are surrounded by cyst cells. Spermiogenesis involves conspicuous modifications such as intracellular movements (diplosome and mitochondria migration, nuclear rotation, and depression) and structural changes (chromatin condensation, shape of mitochondria, and loss of cytoplasm). The mature spermatozoon has a spherical nucleus with a deep, axial nuclear fossa, and an unusual notch, shaped like a bow tie. The short midpiece contains four spherical mitochondria and encircles the basal body of the flagellum. It is concluded that the A. schlegeli spermatozoon is of a primitive type, but that it is characterized by a unique feature which may provide a useful systematic character.

Resolution of the Acanthopagrus black seabream complex based on mitochondrial and amplified fragment‐length polymorphism analyses

“…The NJ and PCA analyses produced identical topologies for the AFLP data ( Fig. 3) and clearly distinguished species that can also be diagnosed based on TRac, anal-fin colour and sperm ultrastructure Gwo & Gwo, 1993;Gwo, 1994;J.-C. Gwo, unpubl. data Notably, AFLP and mitochondrial cytochrome b sequences recovered some incongruent relationships (Figs 3 and 4); more critically, cytochrome b analyses were unable to distinguish two species: A. schlegelii and A. sivicolus.…”

“…The NJ and PCA analyses produced identical topologies for the AFLP data (Fig. 3) and clearly distinguished species that can also be diagnosed based on TRac, anal‐fin colour and sperm ultrastructure (Jean & Lee, 1992; Gwo & Gwo, 1993; Gwo, 1994; J.‐C. Gwo, unpubl.…”

Comparative Ultrastructures of the Fertilized Egg Envelopes in Danio rerio and Danio rerio var. frankei, Cyprinidae, Teleostei

“…We recorded densities of 10.6±1.6 in a 25 μm 2 for zebrafish and 7.7±1.2 in a 25 μm 2 for leopard danio. As the sperm of teleost do not have acrosome, unlike other vertebrates (Gwo & Gwo, 1993;Kim et al, 2009;Lee et al, 2009), sperm cannot penetrate the egg envelope. Instead, fertilization occurs through a micropyle in the area of the animal pole of egg envelope.…”

Morphology of the fertilizable mature egg in the Acanthopagrus latus, A. schlegeli and Sparus sarba (Teleostei: perciformes: sparidae)

“…Modified from Gwo and Gwo's method (1993), the fertilizable mature eggs are fixed at 4°C for 4 h with 2.5% glutaraldehyde in 0.12 M phosphate buffer (pH7.38) and postfixed with 2% osmium tetroxide in the same buffer for 2 h. Then, the samples are dehydrated in a graded ethyl alcohol series. After dehydration, samples are submerged in acetone to dry at critical point, then coated with gold and lastly observed with JSM‐6300 SEM at 20‐KV accelerating voltage.…”

“…Some significant progress on this aspect have been applied to the systematic classification and comparison of teleost fish (Mattei, 1970; Mattei & Mattei, 1974; Afzelius, 1979; Stein, 1981; Baccetti et al , 1984). Very clear descriptions of the ultrastructures of two different sperm types (Gwo & Gwo, 1993; Gwo et al , 1993; Gwo, 1995) are now available as the basis for differentiating the species. However, studies in this trend are mostly limited in making comparisons of morphology and ultrastructures, rather than applying its findings and morphological measurements to taxonomic analysis for demarcation among these three species.…”