The Chromosomes of a Rat-Kangaroo attributable to Bettongia tropica (Marsupialia:Macropodidae)

Abstract

A male specimen of brush-tailed bettong taken near Cairns in north Queensland and attributable to Bettongia tropica Wakefield, 1967, has 22 chromosomes, i.e. 20 autosomes plus X and Y sex chromosomes. The autosomes are seemingly identical in size and shape to those of Bettongia penicillata ogilbyi (Waterhouse). The larger size of X and Y chromosomes in the tropica specimen is due to the presence of extra constitutive heterochromatin (C-banding material). It is concluded that there is no chromosomal basis for the specific distinction currently afforded to the north Queensland brush-tailed bettong.