Archaeological records from Australia provide the earliest, indirect evidence for maritime crossings by early modern humans, as the islands to the north-west of the continent (Wallacea) have never been connected to the mainland. Suggested in 1977 by Joseph B. Birdsell, the two main routes from Sunda (mainland Southeast Asia) to Sahul (Australia-New Guinea), still in debate today, are a northern route through Sulawesi with a landing in New Guinea, or a southern route through Bali, Timor and thence landing in northern Australia. Here we construct least-cost pathway models of human dispersal from Sunda to Sahul at 65 ka and 70 ka by extending previous out-of-Africa least-cost models through the digitization of these routes. We recover overwhelming support for a northern route into Sahul, with a landing location on present-day Misool Island. Minimal support is also recovered for the southern route at 70 ka, with a possible crossing to Sahul from eastern Timor. Review of archaeological records on the Wallacean islands crossed by our northern route indicate a dearth of archaeological research in this region. Meanwhile, the comparatively better studied southern islands still lack any archaeological dates comparable to those known for initial occupation in Sunda and Sahul. Based on our model results we suggest Misool Island as the initial landing site for early modern humans on Sahul and recommend a future focus on archaeological fieldwork in the northern Wallacean islands.

The Wallacea Archipelago provides an extraordinary laboratory for the study of human colonisation and adaptation, yet few detailed archaeological studies have been conducted in the region that span the earliest phase of human settlement. Laili Cave, in northern Timor-Leste, preserves the oldest human occupation in this insular region with a cultural sequence spanning 11,200 to 44,600 cal BP. Small-bodied vertebrates and invertebrates were recovered to the lowest excavated levels, associated with highly concentrated stone artefacts. We report on human behavioural adaptations within the context of Pleistocene environments and changing landscapes using zooarchaeological, stone artefact, bathymetric, and experimental isotopic analyses. Results indicate that Pleistocene humans used the abundant local chert liberally and engaged in mobile broad-spectrum exploitation of invertebrates and fishes from marine, estuarine, and freshwater environments within close proximity of Laili Cave. The faunal assemblage indicates heterogeneous but relatively stable environments during the late Pleistocene. Variability in subsistence strategies over time appears to be a response to changing landscapes and concomitant local resources. This record contrasts with marine specialisations evident from other sites in Timor-Leste and within the broader Wallacean region.Full Tex

Caves have been an important source of vertebrate fossils for much of Southeast Asia, particularly for the Quaternary. Despite this importance, the mechanisms by which vertebrate remains accumulate and preserve in Southeast Asian caves has never been systematically reviewed or examined. Here, we present the results of three years of cave surveys in Indonesia and Timor-Leste, describing cave systems and their attendant vertebrate accumulations in diverse geological, biogeographical, and environmental settings. While each cave system is unique, we find that the accumulation and preservation of vertebrate remains are highly dependent on local geology and environment. These factors notwithstanding, we find the dominant factor responsible for faunal deposition is the presence or absence of biological accumulating agents, a factor directly dictated by biogeographical history. In small, isolated, volcanic islands, the only significant accumulation occurs in archaeological settings, thereby limiting our understanding of the palaeontology of those islands prior to human arrival. In karstic landscapes on both oceanic and continental islands, our understanding of the long-term preservation of vertebrates is still in its infancy. The formation processes of vertebrate-bearing breccias, their taphonomic histories, and the criteria used to determine whether these represent syngenetic or multiple deposits remain critically understudied. The latter in particular has important implications for arguments on how breccia deposits from the region should be analysed and interpreted when reconstructing palaeoenvironments.

The order Dasyuromorphia is a diverse radiation of faunivorous marsupials, comprising >80 modern species in Australia and New Guinea. It includes dasyurids, the numbat (the myrmecobiid Myrmecobius fasciatus) and the recently extinct thylacine (the thylacinid Thylacinus cyncocephalus). There is also a diverse fossil record of dasyuromorphians and “dasyuromorphian-like” taxa known from Australia. We present the first total evidence phylogenetic analyses of the order, based on combined morphological and molecular data (including a novel set of 115 postcranial characters), to resolve relationships and calculate divergence dates. We use this information to analyse the diversification dynamics of modern dasyuromorphians. Our morphology-only analyses are poorly resolved, but our molecular and total evidence analyses confidently resolve most relationships within the order, and are strongly congruent with recent molecular studies. Thylacinidae is the first family to diverge within the order, and there is strong support for four tribes within Dasyuridae (Dasyurini, Phascogalini, Planigalini and Sminthopsini). Among fossil taxa, Ankotarinja and Keeuna do not appear to be members of Dasyuromorphia, whilst Barinya and Mutpuracinus are of uncertain relationships within the order. Divergence dates calculated using total evidence tip-and-node dating are younger than both molecular node-dating and total evidence tip-dating, but appear more congruent with the fossil record and are relatively insensitive to calibration strategy. The tip-and-node divergence dates indicate that Dasyurini, Phascogalini and Sminthopsini began to radiate almost simultaneously during the middle-to-late Miocene (11.5–13.1 MYA; composite 95% HPD: 9.5–15.9 MYA); the median estimates for these divergences are shortly after a drop in global temperatures (the middle Miocene Climatic Transition), and coincide with a faunal turnover event in the mammalian fossil record of Australia. Planigalini radiated much later, during the latest Miocene to earliest Pliocene (6.5 MYA; composite 95% HPD: 4.4–8.9 MYA); the median estimates for these divergences coincide with an increase in grass pollen in the Australian palynological record that suggests the development of more open habitats, which are preferred by modern planigale species. Our results provide a phylogenetic and temporal framework for interpreting the evolution of modern and fossil dasyuromorphians, but future progress will require a much improved fossil record.

Wallacea is the transitional biogeographic zone between the continents of Sunda (Southeast Asia) and Sahul (Australian-New Guinea). It consists of a series of island chains unique in the region for never having been connected to either continent. Movement of early modern humans from Sunda to Sahul during the late Pleistocene required dispersal through Wallacea, and hence would have necessitated sea crossings. However, the archeological evidence for early modern humans in Wallacea is still a work in progress, and none of it pre-dates the archeological record from Sahul. While numerous models of this significant colonization event have been proposed, selecting the most likely model for first landfall in Sahul using current archeological evidence has proven difficult, if not impossible. Here the late Pleistocene archeological evidence of early modern humans from Wallacea and its neighbors are reviewed, and the key colonization models that have been proposed are explored. We consider the use of computer simulations and the input variables necessary to test the likelihood of the different colonization models. We highlight the importance of the greater than 100 additional submerged islands observed within the Wallacean archipelago following a simple analysis of bathymetric data and sea-level curves, and their potential impacts on the dispersal and ecology of early human colonizers.No Full Tex

The palaeogeography of the Wallacea Archipelago is a significant factor in understanding early modern human colonization of Sahul (Australia and New Guinea), and models of colonization patterns, as well as archaeological survey and site interpretation, are all heavily dependent on the specific palaeogeographic reconstruction employed. Here we present five reconstructions for the periods 65, 60, 55, 50, and 45 000 years ago, using the latest bathometric chart and a sea‐level model that is adjusted to account for the average uplift rate known from Wallacea. Using this data we also reconstructed island areal extent as well as topography for each time period. These reconstructions were then used to estimate visibility for each island in the archipelago, and finally to model how intervisible each island was during the period of likely human colonization. Our models provide the first evidence for intervisibility between Timor and Australia at ca. 65–62 ka and 47–12 ka, the second of which is notable for its overlap with the oldest radiocarbon dates from Timor‐Leste and Australia. Based on intervisibility alone, however, our study suggests that the northern route into Papua New Guinea was the most parsimonious route for first modern human entry into Sahul. Our study provides archaeologists with an important baseline from which to conduct physical surveys, interpret archaeological data, and theorize the colonization of Wallacea and Sahul. © 2017 The Authors. Archaeological Prospection Published by John Wiley & Sons Ltd.