COMPARATIVE SPERMATOLOGY IN DASYPODIDAE-II (CHAETOPHRACTUS-VELLEROSUS, ZAEDYUS-PICHIY, EUPHRACTUS-SEXCINCTUS, TOLYPEUTES-MATACUS, DASYPUS-SEPTEMCINCTUS AND DASYPUS-NOVEMCINCTUS)

At present there is increasing interest in the phylogeny and evolution of reproductive systems. Comparative sperm morphology and relationshi ps of spermatozoa sizes have been studied in Chaetophractus vellerosus (lesser hairy or crying armadillo), Zaedyus pichiy (pichi), Euphractu s sexcinctus (yellow armadillo), Tolypeutes matacus (Azara's domed arm adillo), Dasypus septemcinctus (seven-banded long-nosed armadillo) and Dasypus novemcinctus (nine-banded long-nosed armadillo) (Dasypodidae) . The spermatozoa were observed in phase contrast microscopy and their linear dimensions were measured from Giemsa and silver stained spread s. Fine structure of the spermatozoa were also studied. The sperm head s in Ch. vellerosus, Z. pichiy and E. sexcinctus are very large in the frontal view and flattened in the profile one. Electron microscopy co nfirmed their slim heads. T. matacus sperm head presents a characteris tic laterocaudal nuclear extension. D. septemcinctus and D. novemcinct us spermatozoa are similar to those of the other eutherians. These res ults and their comparisons with spermatozoa of armadillos suggest that sperm shape and size are not constant across taxa in Dasypodidae.