Morphology, morphometry and ultrastructure of captive six-banded armadillo (Euphractus sexcinctus) sperm

We analyzed the sperm characteristics of captive six-banded armadillos (Euphractus sexcinctus), by the assessment of sperm morphology, morphometry, and ultrastructure. In general, armadilloʹs ejaculates present more than 80% of sperm within the range considered normal for sperm morphology currently accepted for other mammals. Coiled tails (3.9%) and detached heads (2.8%) were the defects most frequently verified. The morphometric analysis revealed that the total length of six-banded armadillo sperm is 77.6 ± 1.2 μm, and the length of the tail is 64.7 ± 1.1 μm on average. They also present a big head that corresponds to 16.6% of the entire sperm. Through transmission electron microscopy, we identified the presence of electron lucent points into the nucleus and the presence of about 45 mitochondria spirals in the mitochondrial sheath midpiece as a peculiarity of the six-banded armadillo sperm.