Unusual structural changes in mitochondria during spermiogenesis in the oribatid mite, Hafenrefferia gilvipes (Acari).

During spermiogenesis in the oribatid mite, Hafenrefferia gilvipes, striking alterations in the structure and location of mitochondria in spermatids were observed. The structural changes include formation of a single, distended annular crista, which subsequently becomes tubular. Initially, the mitochondria are located in central regions of the cytoplasm, they then move first to the plasmalemma and subsequently to the nuclear envelope, and finally are engulfed in the nuclear material.