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THE living pandas are restricted to the mountains of south-eastern Asia where both the giant panda (Aeluropoda) and the lesser panda (Ailurus) occur. They overlap in geographical range only in Szechuan, China, and there they are separated altitudinally, with the lesser panda favouring higher elevations1. Pleistocene records extend the range of the giant panda into Burma and eastern China, but the lesser panda has apparently not had a significantly wider range during the Quaternary2. Considerable controversy surrounds the phylogenetic relationships of both genera as they represent some of the most derived of terrestrial Carnivora. Recent marshalling of anatomical evidence on the giant panda has demonstrated its fundamental affinity with other members of the Ursidae3. The position of the lesser panda is equivocal although it is usually assigned to the Procyonidae. Procyonids are widely thought to be restricted to the New World, but recent work on various Oligocene and early Miocene forms in Europe4and North America5indicate that the procyonids had a Holarctic distribution at that time. Regardless of its broader phylogenetic affinity, the presence of medial and late Miocene relatives of the lesser panda in Pakistan and western Europe (Sivanasua Pilgrim, 1931=Schlossericyon Crusafont, 1959)6and their absence in the New World makes an Old World origin for this group highly likely. Thus the discovery of a single tooth in North America almost identical to European specimens of the extinct lesser panda Parailurus is unexpected, and must be explained by immigration from Asia.

A PRELIMINARY study has been carried out on fossil remains (unearthed in the British Museum) from a travertine deposit in Tasmania. Regardless of the precise taxonomic assignments ultimately given to this material, the evidence we present that a diverse fauna of diprotodont marsupials existed in Australia in late Oligocene time is of considerable importance. This evidence gives tangible support to the hypothesis that marsupials have been residents of the Australian continent since the early Tertiary at least. The basic differentiation of herbivorous Diprotodonta from Marsupicarnivora (Ride, 1964) very likely took place before the separation of Australia from Antarctica. By late Oligocene time Tasmania was situated near 52°S latitude1bathed by warmer seas2and the travertine accumulated in an equable warm–temperate to subtropical environment supporting a rich forest vegetation3–5the closest living equivalents of which occur in the uplands of New Guinea and New Caledonia. Present-day representatives of some of the fossil marsupials from the travertine still inhabit such tropical environments in northern Australia and New Guinea.

A controversy has arisen over the terms to be applied to certain cusps of the marsupial upper molar as the result of divergent views over the precedence of functional or structural considerations. It is generally accepted that the posterolingual cusp in the molars of mammals has arisen in a number of ways. Regardless of origin they are often termed a ‘hypocone’ because of their analogous occlusal relationship with the trigonid of the lower molars. In diprotodontian marsupials, however, the posterolingual cusp is homologous with the metaconule, as demonstrated by its linkage through the postprotocrista with the protocone and metacone. This structural relationship is important to the determination of homology, which is fundamental to phylogeny reconstruction.