northern nail-tail wallaby (Onychogalea unguifera)

I hoped to see this species in Taronga, but I was misinformed and it had already left the collection a couple of years ago... So, Onychogalea is the only macropod genus still missing on my zoo mammal list. (unless some zoo keeps Dorcopsulus and/or Lagostrophus)

Depends on whether you count Wadderin Sanctuary as a zoo