Figure 1.

Bright field microscopy of naked mole-rat spermatozoa stained with SpermBlue and showing evident sperm polymorphism. a) normal spermatozoon; b) compressed head; c) lobed head and curled tail; d) cone-shaped head; e) double macro-heads; f-h) multi-lobed elongated heads; g) head without acrosome; i) micro-head; j) amorphous head; k) apparent nuclear vacuoles representative of fragmentation. MP = midpiece, ACR = acrosome.