The concepts of biogeographical regions and areas of endemism are briefly reviewed prior to a discussion of what constitutes a natural biogeographical unit. It is concluded that a natural biogeographical unit comprises a group of endemic species that share a geological history. These natural biogeographical units are termed Wallacean biogeographical units in honour of the biogeographer A.R. Wallace. Models of the geological development of Indonesia and the Philippines are outlined. Areas of endemism within Wallacea are identified by distributional data, and their relationship to each other and to the adjacent continental regions are evaluated using molecular phylogenies from the literature. The boundaries of these areas of endemism are in broad agreement with earlier works, but it is argued that the Tanimbar Islands are biologically part of south Maluku, rather than the Lesser Sundas, and that Timor (plus Savu, Roti, Wetar, Damar, and Babar) and the western Lesser Sundas form areas of endemism in their own right. Wallacean biogeographical units within Wallacea are identified by congruence between areas of endemism and geological history. It is concluded that although Wallacea as a whole is not a natural biogeographical region, neither is it completely artificial as it is formed from a complex of predominantly Australasian exotic fragments linked by geological processes within a complex collision zone. The Philippines are argued to be an integral part of Wallacea, as originally intended. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 193–212.

The New Zealand Subantarctic Islands, emergent remnants of the Campbell Plateau, were given World Heritage status in 1998 in recognition of their importance to global biodiversity. We describe the flora and fauna of these islands and discuss the results of recent phylogenetic analyses. Part of the New Zealand Subantarctic biota appears to be relictual and to be derived from west Gondwana. The relictual element is characterized by genera endemic to the Campbell Plateau that show relationships with taxa of the southern South Island, New Zealand, southern South America, and the north Pacific. In contrast, a younger, east Gondwanan element is composed of species that are either taxonomically identical to widespread mainland species, or endemic species with close New Zealand relatives. Area cladograms support the inclusion of the southern South Island, New Zealand and Macquarie Island (although this is separate geologically) as parts of the Campbell Plateau, but suggest the Chatham Rise and Torlesse terranes of the eastern South Island, New Zealand were originally parts of east Gondwana. East and west Antarctica acted as independent plates during the breakup of Gondwana, and were separated by oceanic crust until a compressive phase sutured them along the trace of the trans‐Antarctic mountains during the early Tertiary. The Campbell Plateau microcontinent was connected to west Antarctica until its separation at 80 Mya, contemporaneous with the separation of the southern portion of the Melanesian rift from east Gondwana. Presently the Campbell Plateau is joined to the Melanesian Rift along the Alpine Fault. Cenozoic plate tectonic reconstructions place the Campbell Plateau adjacent to the Melanesian Rift throughout the rift–drift phase, relative motion being confined to strike–slip movement over the last 20 Myr. Our synthesis of phylogenetic and plate tectonic evidence suggests that the Alpine Fault is the most recent development of a much older extensional rift/basin boundary originally separating west and east Gondwana. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 95–115.

A. R. Wallace's name will always be linked with what was known as the Malay Archipelago, and thus it seems appropriate to reassess his contribution to Indonesian biogeography. Wallace is often regarded as the founder of 'dispersalist' biogeography. However, this simplified view seriously misrepresents Wallace's position, which was that animal and plant distributions in Indonesia could be understood in terms of the region's geological history. This view is contrasted with that of dispersalist biogeography, which is that present distributions are the result of unique events, that the present is a consequence of past accidents. The results of Wallace's work are outlined and are reinterpreted in the light of modern evidence about the tectonic development of this region. It is concluded that Wallace's observations are broadly intelligible in the light of what is known about Indonesia's geological history. There is much to gain by biogeographers and geologists working together more closely in Indonesia, for there are many outstanding problems that require resolution. This then is one future direction that may be taken as we stand at the crossroads.

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The placement of Leptusa chiltoni is restored to its original status as sole member of the genus Baeostethus. Baeostethus chiltoni is a subantarctic intertidal species that is present on the shores of Auckland, Antipodes, and Campbell islands. Baeostethus is concluded to be a member of Liparocephalini based on the absence of seta v on the adult mentum, several setae distributed only on the mesal surface and apex of the galea, and contiguous mesocoxal cavities. The phylogenetic relationships of Liparocephalini are investigated in the context of a previous study and Baeostethus is shown to be a sister taxon to Liparocephalus based on 12 synapomorphies (nine are unique). The majority of Liparocephalini are distributed along the coasts of the northern Pacific rim, some 9000 km away from B. chiltoni. Most are apterous, and with Baeostethus as a relatively derived member of the group, it is difficult to reconcile the biogeographic pattern based on a dispersal event from the northern Pacific to the Campbell Plateau. We argue that the trans-Pacific pattern in Liparocephalini is due to an older contiguous distribution along the coastal margins of Pangea. The data are supported by an alternative area cladogram derived from a rerooted tree, congruence with a Pacific rim pattern seen in intertidal Aegalitinae (Salpingidae), and the distribution and phylogeny of terrestrial Gymnusini (Aleocharinae).