Comparative Spermatology in Dasypodidae (Priodontes maximus, Chaetophractus villosus & Dasypus hybridus)

P. CETICA, J. SASSAROLI, M.S. MERANI AND A. SOLARI

BIOCELL

IHEM-CONICET

Año: 1993 vol. 18 p. 89 - 193

0327-9545

At present there is increasing interest in the phylogeny and evolution of reproductive systems. Comparative sperm morphology and relationships of spermatozoa sizes have been studied in three species of Dasypodidae: Priodontes maximlus (giant armadillo), Chaetophractus villosus (large hairy armadillo) and Dasypus hybridus (mulita armadillo). The spermatozoa were observed in phase contrast microscopy and their linear dimensions were measured from photographs of silver-stained spreads. The sperm heads in P. maximus and Ch. villosus are oval-shaped in the frontal plane and f1attened like a spoon in the sagittal one. Electron microscopy confirmed the extremely plane head of Ch. villosus. On the other hand, in D. hybridus the sperm heads are ellipsoidal in the frontal plane and ensiform in the sagittal planeo In the three species the total length of the spermatozoa is near the average of most eutherians, except rodents. On the contrary, the sperm head length and width of P. maximus and Ch. villosus are exceptionally large among mammals and are very different from D. hybridus, which are nearer to common dimensions. The dichotomy between the large areas of sperm heads of the former species and the usual shape and area of that from D. hybridus, added to the intermediate shape of D. novemcinctus suggest that Edentata contains quite diverging taxa, in agreement with data from comparative anatomy and evolutionary biology.