Morphology of the spermatozoon of a murid rodent from Africa, Dasymys incomtus

The structural organization of the head of the spermatozoon from the Africa n murid rodent Dasymys incomtus was investigated by light and transmission electron microscopy and after incubation in various chemical agents. The re sults show that it is falciform in shape with a bifurcated rostral extensio n lying just caudal to the apical hook. The nucleus protrudes into the base of this extension but it is largely composed of a massive elaboration of t he sperm head cytoskeleton which is very resistant to dispersion by chemica l agents. This elaborate accessory structure of the sperm head shows simila r morphology to the ventral processes on the sperm head of Australasian hyd romyine rodents. The possible functional and evolutionary significance of t hese findings are discussed.