Observations on the chromosomes and reproductive systems of four macropodine interspecific hybrids (Marsupialia: Macropodidae)

Four interspecific hybrids (male parent first), Macropus robustus X M. rufus (a female), Wallabia bicolor X M. rufogriseus (a male), M. agilis X M. rufogriseus (a male) and M. eugenii X M. dorsalis (a male), have been verified by their chromosome number and morphology. In the hybrid W. bicolor X M. rufogriseus mosaicism occurred in the lymphocytes for the number of Y chromosomes present. The pelage and skull of each hybrid showed some characteristics of each of the parent species. All hybrids were sterile. The male hybrids had scrotal testes with abundant tubules but no spermatogenesis. The female hybrid lacked the left ovary and had an otherwise complete reproductive system. The potential use of the hybrids involving M. rufogriseus for cell biological studies is discussed.