Spermatozoa of Conger myriaster observed by electron microscopy

Abstract

We examined the morphological features of spermatozoa from Conger myriaster by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Spermatozoa consisted of three regions, a head, neck and flagellum. Total length was approximately 40 μm, with the head 3 μm, neck 0.5 μm and flagellum about 37 μm. The head was crescent-shaped, with a mitochondrion on the concave surface. The neck, with an attached rootlet, consisted of two constrictions close to the base of the flagellum. Two bundles extending from the proximal centrioles existed on both the convex and concave surfaces of the sperm head. The flagellum showed a 9+0 axonemal pattern. Some flagella showed a coiled form, the developmental mechanism of which was unclear. These features were compared with those of other Anguilliformes.