Gray nominated his earlier description of Kangurus pencillatus as the type species, now recognised in the combination Petrogale penicillata (brush-tailed rock-wallaby).

[6] However, these studies also revealed that mitochondrial and nuclear DNA sequences resulted in different phylogenies, a phenomenon called cytonuclear discordance.

[7] The medium-sized, often colourful and extremely agile rock-wallabies live where rocky, rugged and steep terrain can provide daytime refuge.

Their reliance on refuges leads to the rock-wallabies living in small groups or colonies, with individuals having overlapping home ranges of about 15 hectares each.

Scientists consider red foxes the major reason for the recent extinctions, along with competing herbivores, especially goats, sheep and rabbits, diseases such as toxoplasmosis and hydatidosis, habitat fragmentation and destruction, and a lower genetic health due to the increasing isolation of colonies.

Habitat conservation and pest management addressing red foxes and goats appear to be the most urgent recovery actions to save the various species.