Evolutionary sperm morphology and morphometry in armadillos

P. CETICA, A. SOLARI, M.S. MERANI, J. DE ROSAS AND M. BURGOS

JOURNAL OF SUBMICROSCOPIC CYTOLOGY AND PATHOLOGY

Editrice Compositori

Año: 1998 vol. 30 p. 309 - 314

1122-9497

Little is known about the evolution of vertebrate spermatozoa. In most eutherian taxa a high degree of uniformity in sperm shapes and dimensions among species was observed. The aim of this work is to trace a possible evolutionary change in sperm morphology and morphometry in dasypodids. The main difference between the spermatozoa of the studied armadillos is the shape of the sperm heads. We have classified the spermatozoa into 4 different groups according with their head shapes. Sperm from group 1 (Dasypus) are considered ancestral and are clearly separated from the others. The remaining sperm types are derivative ones; those from group 2 (Tolvpeutes) are farther from those of groups 3 (Priodontes and Cabassous) and 4 (Chaetophractus, Zaedyus  and Euphractus) which would have recently differentiated from  each other. The sperm shape and size are not constant across taxa in armadillos; an important evolutive differentiation was established on the sperm morphology and morphometry between the different genera in Dasypodidae.