| Abstrakt: |
Previous studies of Ctenomys species from Central and Western Argentina, referred to as the mendocinus-group, which included a single C. azarae specimen, showed that they share a similar karyotype of 2n = 47–48, a complex chromosomal polymorphism and heterochromatic short arms in most of biarmed autosomes. In this study karyotypes of 46 specimens of C. azarae from nine local populations from La Pampa and Cordoba Provinces (Argentina) were analyzed. Diploid numbers ranged from 2n=46 to 2n=48 and the G-banding pattern was identical to the other species of the mendocinus-group. As in C. mendocinus and C. porteousi, heterochromatin was highly variable, exhibiting a large number of polymorphisms that involved C-positive blocks. Our data also revealed that the same polymorphism displayed in pair A1, was present in five C. azarae populations. Another significant finding was the presence of the homomozygous karyotype (2n = 46), which was absent in 106 previously studied specimens of C. porteousi and C. mendocinus, in two C. azarae populations. Cytogenetic, morphometric, and sperm morphology studies of the mendocinus-group suggest recent allopatric speciation events, in which chromosomal rearrangements did not play a central role. |
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