Reinvestigation of the chromosomes of a male owl monkey (Aotus trivirgatus) and its hybrid son

A male owl monkey, probably belonging to Aotus trivirgatus nigriceps, was found to have 51 chromosomes. Since the Y chromosome is lacking, the odd diploid number probably is the result of a Y-autosome translocation. However, there are two autosomes from different pairs that theoretically could contain the Y. This specimen produced a male young with a female A. trivirgatus griseimembra, having a karyotype with 54 chromosomes. The diploid number of the hybrid is 52, including 28 paired and 24 unpaired elements. Comparison of the paternal, maternal and hybrid karyotypes using Q- and C-banding techniques permit conclusions on the rearrangements (fusions, reciprocal translocations, inversions and insertions) that could possibly have led to the karyological differences between both subspecies.