Pseudocheirus peregrinus (Ogilby 1837, Scanlon and Sprague 1984) is the extant ringtail possum. It has grasping feet and hands (with two thumbs) and a prehensile tail, convergent with arboreal didelphids. Cat-sized Pseudocheirus feeds on leaves. Phascolarctos, the koala, is a relative.

Phascolarctos cinereus (de Blainville 1816; recent; 60-85cm in length) is the koala native to Australia. This herbivore climbs trees with two thumbs and a medial toe not found in sister taxa.

de Blainville H 1816. Prodrome d'une nouvelle distribution systématique du règne animal. Bulletin de la Société Philomáthique, Paris (in French). 8: 113–124.

Ogilby W 1837. Observations on the opposable power of the thumb in certain mammals, considered as a zoological character; and on the natural affinities which subsist between the Bimana, Quadrumana, and Pedimana. The Magazine of Natural History (Charlesworth) 1: 449-459.

Scanlon JD and Sprague T 1984. A study of the riingtail possum Pseudocheirus peregrinus. DOI: 10.13140/RG.2.1.4480.4647

wiki/Phascolarctos
wiki/Koala
wiki/Pseudocheirus