According to "Nachttierhäuser in Zoologischen Gärten" Wild Life Sydney kept Mountain Brushtail Possum (Trichosurus cunninghami) somewhere in this decade.
The booklet also mentions quite a few rarities in the past collections of the nocturnal houses of Perth and Taronga, most notable Spectacled Hare-Wallaby (P), Leadbeater's Possum (P, T), Mountain Pygmy Possum (T), Western Pygmy Possum (P), Spotted Cuscus (P, T) and Scaly-tailed Possum (P). The trio I mentioned in April for Taronga, aren't listed (but Kowari is for Perth).
The booklet also mentions quite a few rarities in the past collections of the nocturnal houses of Perth and Taronga, most notable Spectacled Hare-Wallaby (P), Leadbeater's Possum (P, T), Mountain Pygmy Possum (T), Western Pygmy Possum (P), Spotted Cuscus (P, T) and Scaly-tailed Possum (P). The trio I mentioned in April for Taronga, aren't listed (but Kowari is for Perth).