Ultrastructural observations on the Sperm of two Apodemus species,Apodemus agrarius coreae and Apodemus speciosus peninsulae,in Korea

Sperm morphology of Apodemus agrarius coreae, Apodemus speciosus peninsulae, laboratory mouse and rat were studied. In the total length of the sperm of A. a. coreae, A.s. peninsulae, the mouse and rat was about 133μm, 124μm, 131μm and 192μm, respectively. Two Apodemus sperm heads had a fish hook shape, while the mouse sperm head had a hook shape; thus, the sperm heads of genus Apodemus were somewhat like those of the mouse. The rat sperm head was unlike the other species in that it had a falciform shape. In addition, two Apodemus spermatozoa had two well-developed ventral spurs (Vs), and the mouse sperm head also had two similar small Vs, but rat sperm of the anterior acrosomal portion of sperm. In the neck region, the vault formerly occupied by the proximal centriole was retained in a niche in the dense substance of the connecting piece ni the spermatozoa of two Apodemus species, the mouse and the rat. The neck region of two Apodemus spermatozoa was surrounded by the scroll of a redundant nuclear envelope and a few large mitochondoria, except a fold of the redundant nuclear envelope. Since a very similar sperm head morphology occures in the two Apodemus species and the mouse, it suggests that these genera are sister groups, to the exclusion of the rat