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Tropical Southeast (SE) Asia harbors extraordinary species richness and in its entirety comprises four of the Earth's 34 biodiversity hotspots. Here, we examine the assembly of the SE Asian biota through time and space. We conduct meta-analyses of geological, climatic, and biological (including 61 phylogenetic) data sets to test which areas have been the sources of long-term biological diversity in SE Asia, particularly in the pre-Miocene, Miocene, and Plio-Pleistocene, and whether the respective biota have been dominated by in situ diversification, immigration and/or emigration, or equilibrium dynamics. We identify Borneo and Indochina, in particular, as major “evolutionary hotspots” for a diverse range of fauna and flora. Although most of the region's biodiversity is a result of both the accumulation of immigrants and in situ diversification, within-area diversification and subsequent emigration have been the predominant signals characterizing Indochina and Borneo's biota since at least the early Miocene. In contrast, colonization events are comparatively rare from younger volcanically active emergent islands such as Java, which show increased levels of immigration events. Few dispersal events were observed across the major biogeographic barrier of Wallace's Line. Accelerated efforts to conserve Borneo's flora and fauna in particular, currently housing the highest levels of SE Asian plant and mammal species richness, are critically required. [ABSTRACT FROM AUTHOR]

Abstract: Two contrasting parallel tectonic sutures can be recognised through the Yunnan–Thailand region of mainland Southeast Asia; they are sutures of the Devonian–Triassic Palaeo-Tethys Ocean and a Permian back-arc basin. The Changning–Menglian and Inthanon suture zones are regarded as the Palaeo-Tethys Suture Zone. The Jinghong–Nan–Sra Kaeo suture is regarded as a closed back-arc basin. The Sukhothai Zone is no longer treated as a part of the Sibumasu Terrane, but is defined as the core part of the Permian island-arc system developed on the western margin of the Indochina Terrane. Two tectonic events are interpreted from the parallel sutures; a Late Permian collapse of the back-arc basin and a mid-Triassic collision of Sibumasu to the Sukhothai Arc of Indochina (=closure of the Palaeo-Tethys). The Early–early Middle Triassic thermotectonism of Vietnam as linked to the Indosinian orogeny by some authors is incompatible with the suggested timing of Sibumasu collision, but instead it is temporally closer to the back-arc compression of western Indochina. [Copyright &y& Elsevier]