Ultrastructure of epididymal spermatozoa in three social African mole-rats of the genus Cryptomys (Rodentia: Bathyergidae): conservatism in sperm morphology

Abstract

The morphology, size and three-dimensional structure of spermatozoa from three representatives of the genus Cryptomys were investigated. To date, there has been no study to either elucidate the morphological features or relative dimensions of spermatozoa in the genus Cryptomys specifically, or in the Bathyergidae as a whole. Semen samples were collected from the whole region of the epididymides, in one eusocial species, the Damaraland mole-rat, Cryptomys damarensis and two social subspecies the common mole-rat, Cryptomys hottentotus hottentotus and the highveld mole-rat, Cryptomys hottentotus pretoriae. Spermatozoa were processed using standard procedures for scanning electron microscopy (SEM). Whole sperm dimensions were measured and morphological characteristics documented. The results reveal a degree of conservation of morphological structure of the spermatozoa within the genus Cryptomys, with a slight plasticity in the size of some sperm components. Key words: Bathyergidae, spermatozoa, sperm morphology, scanning electron microscopy.