ABSTRACT
Through appropriate scanning electron microscope (SEM) processing, the shape and the surface structures of just-mature eggs are preserved integrally for observation and measuring to guarantee accurate comparison and prediction on the phylogenetic relationships among three species of teleost, i.e. Acanthopagrus latus, Acanthopagrus schlegeli and Sparus sarba of Sparidae. Eggs in all three species can be categorized as type III eggs. Specifically, a regular pattern is found in the arrangement of micropyle and its surrounding pore canals from the inspected surface structures of the mature eggs in three species. Other than these similarities in egg surface structures, several differences in micropyle structures, micropyle region and size of pore canals are also observed in eggs of respective species. Comprehension and accurate data are statistically computed and analyzed through hierarchical cluster analysis to provide solid species-specific evidences and standardized empirical reference for accurate species identification and phylogeny determination.
Subject(s)
Ovum/ultrastructure , Perciformes/anatomy & histology , Animals , Biometry , Cluster Analysis , Female , Male , Microscopy, Electron, Scanning , PhylogenyABSTRACT
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.
