Publications by authors named "Richard G Roberts"

74 Publications

Human occupation of northern India spans the Toba super-eruption ~74,000 years ago.

Nat Commun 2020 02 25;11(1):961. Epub 2020 Feb 25.

School of Social Science, University of Queensland, St Lucia, QLD, 4072, Australia.

India is located at a critical geographic crossroads for understanding the dispersal of Homo sapiens out of Africa and into Asia and Oceania. Here we report evidence for long-term human occupation, spanning the last ~80 thousand years, at the site of Dhaba in the Middle Son River Valley of Central India. An unchanging stone tool industry is found at Dhaba spanning the Toba eruption of ~74 ka (i.e., the Youngest Toba Tuff, YTT) bracketed between ages of 79.6 ± 3.2 and 65.2 ± 3.1 ka, with the introduction of microlithic technology ~48 ka. The lithic industry from Dhaba strongly resembles stone tool assemblages from the African Middle Stone Age (MSA) and Arabia, and the earliest artefacts from Australia, suggesting that it is likely the product of Homo sapiens as they dispersed eastward out of Africa.
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http://dx.doi.org/10.1038/s41467-020-14668-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042215PMC
February 2020

Archaeological evidence for two separate dispersals of Neanderthals into southern Siberia.

Proc Natl Acad Sci U S A 2020 02 27;117(6):2879-2885. Epub 2020 Jan 27.

Institute of Archaeology and Ethnography, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.

Neanderthals were once widespread across Europe and western Asia. They also penetrated into the Altai Mountains of southern Siberia, but the geographical origin of these populations and the timing of their dispersal have remained elusive. Here we describe an archaeological assemblage from Chagyrskaya Cave, situated in the Altai foothills, where around 90,000 Middle Paleolithic artifacts and 74 Neanderthal remains have been recovered from deposits dating to between 59 and 49 thousand years ago (age range at 95.4% probability). Environmental reconstructions suggest that the Chagyrskaya hominins were adapted to the dry steppe and hunted bison. Their distinctive toolkit closely resembles Micoquian assemblages from central and eastern Europe, including the northern Caucasus, more than 3,000 kilometers to the west of Chagyrskaya Cave. At other Altai sites, evidence of earlier Neanderthal populations lacking associated Micoquian-like artifacts implies two or more Neanderthal incursions into this region. We identify eastern Europe as the most probable ancestral source region for the Chagyrskaya toolmakers, supported by DNA results linking the Neanderthal remains with populations in northern Croatia and the northern Caucasus, and providing a rare example of a long-distance, intercontinental population movement associated with a distinctive Paleolithic toolkit.
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http://dx.doi.org/10.1073/pnas.1918047117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022189PMC
February 2020

Combined organic biomarker and use-wear analyses of stone artefacts from Liang Bua, Flores, Indonesia.

Sci Rep 2019 11 26;9(1):17553. Epub 2019 Nov 26.

Centre for Archaeological Science, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, 2522, Australia.

Organic biomarker and lithic use-wear analyses of archaeological implements manufactured and/or used by hominins in the past offers a means of assessing how prehistoric peoples utilised natural resources. Currently, most studies focus on one of these techniques, rather than using both in sequence. This study aims to assess the potential of combining both methods to analyse stone artefacts, using a set of 69 stones excavated from the cave site of Liang Bua (Flores, Indonesia). Prior to chemical analysis, an initial inspection of the artefacts revealed potential use-wear traces but no visible residues. Gas chromatography mass spectrometry (GC-MS) analysis, including the targeting of 86 lipids, terpenes, terpenoids, alkanes and their analogues, found compounds with plant or animal origin on 27 of the 69 stones. The artefacts were subsequently cleaned, and use-wear analysis identified traces of use on 43 artefacts. Use-wear analysis confirmed traces of use on 23 of the 27 artefacts with potential use-residues that were determined by GC-MS. The GC-MS results were broadly consistent with the functional classes identified in the later use-wear analysis. This inclusive approach for stone artefact analysis strengthens the identifications made through multiple lines of enquiry. There remain conflicts and uncertainties in specific cases, suggesting the need for further refinement and analyses of the relationships between use-wear and residues.
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http://dx.doi.org/10.1038/s41598-019-53782-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6879511PMC
November 2019

Hominin and animal activities in the microstratigraphic record from Denisova Cave (Altai Mountains, Russia).

Sci Rep 2019 09 26;9(1):13785. Epub 2019 Sep 26.

Centre for Archaeological Science, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, 2522, Australia.

Denisova Cave in southern Siberia uniquely contains evidence of occupation by a recently discovered group of archaic hominins, the Denisovans, starting from the middle of the Middle Pleistocene. Artefacts, ancient DNA and a range of animal and plant remains have been recovered from the sedimentary deposits, along with a few fragmentary fossils of Denisovans, Neanderthals and a first-generation Neanderthal-Denisovan offspring. The deposits also contain microscopic traces of hominin and animal activities that can provide insights into the use of the cave over the last 300,000 years. Here we report the results of a micromorphological study of intact sediment blocks collected from the Pleistocene deposits in the Main and East Chambers of Denisova Cave. The presence of charcoal attests to the use of fire by hominins, but other evidence of their activities preserved in the microstratigraphic record are few. The ubiquitous occurrence of coprolites, which we attribute primarily to hyenas, indicates that the site was visited for much of its depositional history by cave-dwelling carnivores. Microscopic traces of post-depositional diagenesis, bioturbation and incipient cryoturbation are observed in only a few regions of the deposit examined here. Micromorphology can help identify areas of sedimentary deposit that are most conducive to ancient DNA preservation and could be usefully integrated with DNA analyses of sediments at archaeological sites to illuminate features of their human and environmental history that are invisible to the naked eye.
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http://dx.doi.org/10.1038/s41598-019-49930-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6763451PMC
September 2019

Minimum founding populations for the first peopling of Sahul.

Nat Ecol Evol 2019 07 17;3(7):1057-1063. Epub 2019 Jun 17.

Global Ecology, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia.

The timing, context and nature of the first people to enter Sahul is still poorly understood owing to a fragmented archaeological record. However, quantifying the plausible demographic context of this founding population is essential to determine how and why the initial peopling of Sahul occurred. We developed a stochastic, age-structured model using demographic rates from hunter-gatherer societies, and relative carrying capacity hindcasted with LOVECLIM's net primary productivity for northern Sahul. We projected these populations to determine the resilience and minimum sizes required to avoid extinction. A census founding population of between 1,300 and 1,550 individuals was necessary to maintain a quasi-extinction threshold of ≲0.1. This minimum founding population could have arrived at a single point in time, or through multiple voyages of ≥130 people over ~700-900 years. This result shows that substantial population amalgamation in Sunda and Wallacea in Marine Isotope Stages 3-4 provided the conditions for the successful, large-scale and probably planned peopling of Sahul.
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http://dx.doi.org/10.1038/s41559-019-0902-6DOI Listing
July 2019

Age estimates for hominin fossils and the onset of the Upper Palaeolithic at Denisova Cave.

Nature 2019 01 30;565(7741):640-644. Epub 2019 Jan 30.

Oxford Radiocarbon Accelerator Unit, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK.

Denisova Cave in the Siberian Altai (Russia) is a key site for understanding the complex relationships between hominin groups that inhabited Eurasia in the Middle and Late Pleistocene epoch. DNA sequenced from human remains found at this site has revealed the presence of a hitherto unknown hominin group, the Denisovans, and high-coverage genomes from both Neanderthal and Denisovan fossils provide evidence for admixture between these two populations. Determining the age of these fossils is important if we are to understand the nature of hominin interaction, and aspects of their cultural and subsistence adaptations. Here we present 50 radiocarbon determinations from the late Middle and Upper Palaeolithic layers of the site. We also report three direct dates for hominin fragments and obtain a mitochondrial DNA sequence for one of them. We apply a Bayesian age modelling approach that combines chronometric (radiocarbon, uranium series and optical ages), stratigraphic and genetic data to calculate probabilistically the age of the human fossils at the site. Our modelled estimate for the age of the oldest Denisovan fossil suggests that this group was present at the site as early as 195,000 years ago (at 95.4% probability). All Neanderthal fossils-as well as Denisova 11, the daughter of a Neanderthal and a Denisovan-date to between 80,000 and 140,000 years ago. The youngest Denisovan dates to 52,000-76,000 years ago. Direct radiocarbon dating of Upper Palaeolithic tooth pendants and bone points yielded the earliest evidence for the production of these artefacts in northern Eurasia, between 43,000 and 49,000 calibrated years before present (taken as AD 1950). On the basis of current archaeological evidence, it may be assumed that these artefacts are associated with the Denisovan population. It is not currently possible to determine whether anatomically modern humans were involved in their production, as modern-human fossil and genetic evidence of such antiquity has not yet been identified in the Altai region.
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http://dx.doi.org/10.1038/s41586-018-0870-zDOI Listing
January 2019

Timing of archaic hominin occupation of Denisova Cave in southern Siberia.

Nature 2019 01 30;565(7741):594-599. Epub 2019 Jan 30.

Centre for Archaeological Science, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia.

The Altai region of Siberia was inhabited for parts of the Pleistocene by at least two groups of archaic hominins-Denisovans and Neanderthals. Denisova Cave, uniquely, contains stratified deposits that preserve skeletal and genetic evidence of both hominins, artefacts made from stone and other materials, and a range of animal and plant remains. The previous site chronology is based largely on radiocarbon ages for fragments of bone and charcoal that are up to 50,000 years old; older ages of equivocal reliability have been estimated from thermoluminescence and palaeomagnetic analyses of sediments, and genetic analyses of hominin DNA. Here we describe the stratigraphic sequences in Denisova Cave, establish a chronology for the Pleistocene deposits and associated remains from optical dating of the cave sediments, and reconstruct the environmental context of hominin occupation of the site from around 300,000 to 20,000 years ago.
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http://dx.doi.org/10.1038/s41586-018-0843-2DOI Listing
January 2019

The spatio-temporal distribution of archaeological and faunal finds at Liang Bua (Flores, Indonesia) in light of the revised chronology for Homo floresiensis.

J Hum Evol 2018 11 31;124:52-74. Epub 2018 Aug 31.

Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia; Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Liang Bua, the type site of Homo floresiensis, is a limestone cave on the Indonesian island of Flores with sedimentary deposits currently known to range in age from about 190 thousand years (ka) ago to the present. Recent revision of the stratigraphy and chronology of this depositional sequence suggests that skeletal remains of H. floresiensis are between ∼100 and 60 ka old, while cultural evidence of this taxon occurs until ∼50 ka ago. Here we examine the compositions of the faunal communities and stone artifacts, by broad taxonomic groups and raw materials, throughout the ∼190 ka time interval preserved in the sequence. Major shifts are observed in both the faunal and stone artifact assemblages that reflect marked changes in paleoecology and hominin behavior, respectively. Our results suggest that H. floresiensis and Stegodon florensis insularis, along with giant marabou stork (Leptoptilos robustus) and vulture (Trigonoceps sp.), were likely extinct by ∼50 ka ago. Moreover, an abrupt and statistically significant shift in raw material preference due to an increased use of chert occurs ∼46 thousand calibrated radiocarbon (C) years before present (ka cal. BP), a pattern that continues through the subsequent stratigraphic sequence. If an increased preference for chert does, in fact, characterize Homo sapiens assemblages at Liang Bua, as previous studies have suggested (e.g., Moore et al., 2009), then the shift observed here suggests that modern humans arrived on Flores by ∼46 ka cal. BP, which would be the earliest cultural evidence of modern humans in Indonesia.
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http://dx.doi.org/10.1016/j.jhevol.2018.07.001DOI Listing
November 2018

A reassessment of the early archaeological record at Leang Burung 2, a Late Pleistocene rock-shelter site on the Indonesian island of Sulawesi.

PLoS One 2018 11;13(4):e0193025. Epub 2018 Apr 11.

Centre for Archaeological Science, School of Earth & Environmental Sciences, University of Wollongong, Wollongong, New South Wales, Australia.

This paper presents a reassessment of the archaeological record at Leang Burung 2, a key early human occupation site in the Late Pleistocene of Southeast Asia. Excavated originally by Ian Glover in 1975, this limestone rock-shelter in the Maros karsts of Sulawesi, Indonesia, has long held significance in our understanding of early human dispersals into 'Wallacea', the vast zone of oceanic islands between continental Asia and Australia. We present new stratigraphic information and dating evidence from Leang Burung 2 collected during the course of our excavations at this site in 2007 and 2011-13. Our findings suggest that the classic Late Pleistocene modern human occupation sequence identified previously at Leang Burung 2, and proposed to span around 31,000 to 19,000 conventional 14C years BP (~35-24 ka cal BP), may actually represent an amalgam of reworked archaeological materials. Sources for cultural materials of mixed ages comprise breccias from the rear wall of the rock-shelter-remnants of older, eroded deposits dated to 35-23 ka cal BP-and cultural remains of early Holocene antiquity. Below the upper levels affected by the mass loss of Late Pleistocene deposits, our deep-trench excavations uncovered evidence for an earlier hominin presence at the site. These findings include fossils of now-extinct proboscideans and other 'megafauna' in stratified context, as well as a cobble-based stone artifact technology comparable to that produced by late Middle Pleistocene hominins elsewhere on Sulawesi.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193025PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5894965PMC
July 2018

Monitoring the extent of vertical and lateral movement of human decomposition products through sediment using cholesterol as a biomarker.

Forensic Sci Int 2018 Apr 6;285:93-104. Epub 2018 Feb 6.

Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia; Australian Research Council (ARC) Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales 2522, Australia. Electronic address:

Due to the lack of human decomposition research facilities available in different geographical regions, the extent of movement of human decomposition products from a cadaver into various sedimentary environments, in different climates, has not been able to be studied in detail. In our study, a human cadaver was placed on the surface of a designated plot at the Australian Facility for Taphonomic Experimental Research (AFTER), the only human decomposition facility in Australia, where the natural process of decomposition was allowed to progress over 14days in the Australian summer. Sediment columns (approximately 1m deep) were collected at lateral distances of 0.25m, 0.5m, 1.0m and 2.5m in each of four directions from the centre of the torso. Plot elevation and weather data were also collected. Each sediment column was subdivided, dried and homogenised. A sample was isolated from each sediment subdivision, extracted with hexane, and the hexane extract cleaned with citrate buffer (pH 3), filtered and spiked with cholesterol-D internal standard. After derivatisation with BSTFA+1% TMCS, cholesterol was monitored in the samples using targeted gas chromatography tandem mass spectrometry analysis. A positive result for decomposition products was given if the cholesterol abundance in the test sample was higher than that detected in the 'control' samples of a similar substrate type collected prior to cadaver placement. Within the confines of the experimental design and the measured parameters, lateral leaching was observed over distances of up to 2.5m from the centre of the torso, which was the maximum distance tested in the study. Vertical leaching was detected to depths of up to 49cm below the ground surface. Such data can aid the development of policies related to plot sizing and sediment renewal and regeneration at other human decomposition facilities and at cemeteries. The density and distribution of cholesterol surrounding the cadaver in this study can also help forensic investigators interpret cases involving remains that have been moved or scavenged.
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http://dx.doi.org/10.1016/j.forsciint.2018.01.026DOI Listing
April 2018

Human occupation of northern Australia by 65,000 years ago.

Nature 2017 07;547(7663):306-310

Archaeology and Natural History, School of Culture, History and Language, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.

The time of arrival of people in Australia is an unresolved question. It is relevant to debates about when modern humans first dispersed out of Africa and when their descendants incorporated genetic material from Neanderthals, Denisovans and possibly other hominins. Humans have also been implicated in the extinction of Australia's megafauna. Here we report the results of new excavations conducted at Madjedbebe, a rock shelter in northern Australia. Artefacts in primary depositional context are concentrated in three dense bands, with the stratigraphic integrity of the deposit demonstrated by artefact refits and by optical dating and other analyses of the sediments. Human occupation began around 65,000 years ago, with a distinctive stone tool assemblage including grinding stones, ground ochres, reflective additives and ground-edge hatchet heads. This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans.
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http://dx.doi.org/10.1038/nature22968DOI Listing
July 2017

Single-grain OSL chronologies for the Still Bay and Howieson's Poort industries and the transition between them: Further analyses and statistical modelling.

J Hum Evol 2017 06 15;107:1-13. Epub 2017 Mar 15.

ARC Centre of Excellence for Australian Biodiversity and Heritage, Centre for Archaeological Science, School of Earth & Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.

The chronology of the Still Bay (SB) and Howieson's Poort (HP) lithic industries remains an issue of keen interest because of the central role of these two phases of technological and behavioural innovation within the Middle Stone Age of southern Africa. Several dating studies have been conducted on SB and HP sites, including a pair published by the present authors and our colleagues in 2008 and 2013. These reported the results of systematically applying single-grain optically stimulated luminescence (OSL) dating procedures to 10 sites in South Africa, Lesotho and Namibia to constrain the timing of the start and end of the SB and HP and reveal the existence of a gap of several millennia between them. Alternative ages for these two industries have since been proposed by others for one of these South African sites (Diepkloof Rockshelter) and some concerns have been raised about the procedures used in our earlier studies to estimate the beta dose rates for a small number of samples. Here, we provide an update on our chronology for the SB and HP and address the issues raised about the methods that we used previously to estimate the beta dose rates and their associated uncertainties. To test the sensitivity of our new SB and HP ages to different underlying assumptions, we have run the same statistical model as that used in our 2008 and 2013 studies under three different scenarios. We show that the ages for the different samples are insensitive to how we analytically process or statistically model our data, and that our earlier conclusions about timing of the start and end of the SB and the HP and the probability of a gap between them remain true for two of the three scenarios. We conclude by bringing our study into the context of additional chronometric, stratigraphic and lithic technology studies that have been conducted in the intervening decade.
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http://dx.doi.org/10.1016/j.jhevol.2017.02.004DOI Listing
June 2017

Neandertal and Denisovan DNA from Pleistocene sediments.

Science 2017 May 27;356(6338):605-608. Epub 2017 Apr 27.

Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.

Although a rich record of Pleistocene human-associated archaeological assemblages exists, the scarcity of hominin fossils often impedes the understanding of which hominins occupied a site. Using targeted enrichment of mitochondrial DNA, we show that cave sediments represent a rich source of ancient mammalian DNA that often includes traces of hominin DNA, even at sites and in layers where no hominin remains have been discovered. By automation-assisted screening of numerous sediment samples, we detected Neandertal DNA in eight archaeological layers from four caves in Eurasia. In Denisova Cave, we retrieved Denisovan DNA in a Middle Pleistocene layer near the bottom of the stratigraphy. Our work opens the possibility of detecting the presence of hominin groups at sites and in areas where no skeletal remains are found.
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http://dx.doi.org/10.1126/science.aam9695DOI Listing
May 2017

Early human symbolic behavior in the Late Pleistocene of Wallacea.

Proc Natl Acad Sci U S A 2017 04 3;114(16):4105-4110. Epub 2017 Apr 3.

Australian Research Centre for Human Evolution, Environmental Futures Research Institute, Griffith University, Brisbane, QLD, Australia 4111.

Wallacea, the zone of oceanic islands separating the continental regions of Southeast Asia and Australia, has yielded sparse evidence for the symbolic culture of early modern humans. Here we report evidence for symbolic activity 30,000-22,000 y ago at Leang Bulu Bettue, a cave and rock-shelter site on the Wallacean island of Sulawesi. We describe hitherto undocumented practices of personal ornamentation and portable art, alongside evidence for pigment processing and use in deposits that are the same age as dated rock art in the surrounding karst region. Previously, assemblages of multiple and diverse types of Pleistocene "symbolic" artifacts were entirely unknown from this region. The Leang Bulu Bettue assemblage provides insight into the complexity and diversification of modern human culture during a key period in the global dispersal of our species. It also shows that early inhabitants of Sulawesi fashioned ornaments from body parts of endemic animals, suggesting modern humans integrated exotic faunas and other novel resources into their symbolic world as they colonized the biogeographically unique regions southeast of continental Eurasia.
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http://dx.doi.org/10.1073/pnas.1619013114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5402422PMC
April 2017

The chronostratigraphy of the Haua Fteah cave (Cyrenaica, northeast Libya) - Optical dating of early human occupation during Marine Isotope Stages 4, 5 and 6.

J Hum Evol 2017 04 18;105:69-88. Epub 2017 Mar 18.

McDonald Institute for Archaeological Research, University of Cambridge, Cambridge CB2 3ER, UK.

The paper presents the results of optical dating of potassium-rich feldspar grains obtained from the Haua Fteah cave in Cyrenaica, northeast Libya, focussing on the chronology of the Deep Sounding excavated by Charles McBurney in the 1950s and re-excavated recently. Samples were also collected from a 1.25 m-deep trench (Trench S) excavated during the present project below the basal level of the Deep Sounding. Optically stimulated luminescence (OSL) data sets for multi-grain, single aliquots of quartz for samples from the Middle Trench were previously published. Re-analyses of these OSL data confirm significant variation in the dose saturation levels of the quartz signal, but allow the most robust OSL ages to be determined for comparison with previous age estimates and with those obtained in this study for potassium-rich feldspars from the Deep Sounding. The latter indicate that humans may have started to visit the cave as early as ∼150 ka ago, but that major use of the cave occurred during MIS 5, with the accumulation of the Deep Sounding sediments. Correlations between optical ages and episodes of "Pre-Aurignacian" artefact discard indicate that human use of the cave during MIS 5 was highly intermittent. The earliest phases of human activity appear to have occurred during interstadial conditions (5e and 5c), with a later phase of lithic discard associated with more stadial conditions, possibly MIS 5b. We argue that the "Pre-Aurignacian" assemblage can probably be linked with modern humans, like the succeeding "Levalloiso-Mousterian" assemblage; two modern human mandibles associated with the latter are associated with a modelled age of 73-65 ka. If this attribution is correct, then the new chronology implies that modern humans using "Pre-Aurignacian" technologies were in Cyrenaica as early as modern humans equipped with "Aterian" technologies were in the Maghreb, raising new questions about variability among lithic technologies during the initial phases of modern human dispersals into North Africa.
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http://dx.doi.org/10.1016/j.jhevol.2017.01.008DOI Listing
April 2017

The Challenges of Measuring, Improving, and Reporting Quality in Primary Care.

Ann Fam Med 2017 03;15(2):175-182

Indiana University School of Informatics and Computing, Bloomington, Indiana.

We propose a new set of priorities for quality management in primary care, acknowledging that payers and regulators likely will continue to insist on reporting numerical quality metrics. Primary care practices have been described as complex adaptive systems. Traditional quality improvement processes applied to linear mechanical systems, such as isolated single-disease care, are inappropriate for nonlinear, complex adaptive systems, such as primary care, because of differences in care processes, outcome goals, and the validity of summative quality scorecards. Our priorities for primary care quality management include patient-centered reporting; quality goals not based on rigid targets; metrics that capture avoidance of excessive testing or treatment; attributes of primary care associated with better outcomes and lower costs; less emphasis on patient satisfaction scores; patient-centered outcomes, such as days of avoidable disability; and peer-led qualitative reviews of patterns of care, practice infrastructure, and intrapractice relationships.
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http://dx.doi.org/10.1370/afm.2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5348238PMC
March 2017

A comprehensive database of quality-rated fossil ages for Sahul's Quaternary vertebrates.

Sci Data 2016 Jul 19;3:160053. Epub 2016 Jul 19.

School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.

The study of palaeo-chronologies using fossil data provides evidence for past ecological and evolutionary processes, and is therefore useful for predicting patterns and impacts of future environmental change. However, the robustness of inferences made from fossil ages relies heavily on both the quantity and quality of available data. We compiled Quaternary non-human vertebrate fossil ages from Sahul published up to 2013. This, the FosSahul database, includes 9,302 fossil records from 363 deposits, for a total of 478 species within 215 genera, of which 27 are from extinct and extant megafaunal species (2,559 records). We also provide a rating of reliability of individual absolute age based on the dating protocols and association between the dated materials and the fossil remains. Our proposed rating system identified 2,422 records with high-quality ages (i.e., a reduction of 74%). There are many applications of the database, including disentangling the confounding influences of hypothetical extinction drivers, better spatial distribution estimates of species relative to palaeo-climates, and potentially identifying new areas for fossil discovery.
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http://dx.doi.org/10.1038/sdata.2016.53DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4984482PMC
July 2016

Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia.

Nature 2016 Apr 30;532(7599):366-9. Epub 2016 Mar 30.

Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia), has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts and remains of other extinct endemic fauna, were dated to between about 95 and 12 thousand calendar years (kyr) ago. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13-11 kyr cal. BP). Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago--potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans--is an open question.
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http://dx.doi.org/10.1038/nature17179DOI Listing
April 2016

Climate change not to blame for late Quaternary megafauna extinctions in Australia.

Nat Commun 2016 Jan 29;7:10511. Epub 2016 Jan 29.

The Environment Institute and School of Biological Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.

Late Quaternary megafauna extinctions impoverished mammalian diversity worldwide. The causes of these extinctions in Australia are most controversial but essential to resolve, because this continent-wide event presaged similar losses that occurred thousands of years later on other continents. Here we apply a rigorous metadata analysis and new ensemble-hindcasting approach to 659 Australian megafauna fossil ages. When coupled with analysis of several high-resolution climate records, we show that megafaunal extinctions were broadly synchronous among genera and independent of climate aridity and variability in Australia over the last 120,000 years. Our results reject climate change as the primary driver of megafauna extinctions in the world's most controversial context, and instead estimate that the megafauna disappeared Australia-wide ∼13,500 years after human arrival, with shorter periods of coexistence in some regions. This is the first comprehensive approach to incorporate uncertainty in fossil ages, extinction timing and climatology, to quantify mechanisms of prehistorical extinctions.
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http://dx.doi.org/10.1038/ncomms10511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740174PMC
January 2016

Earliest hominin occupation of Sulawesi, Indonesia.

Nature 2016 Jan;529(7585):208-11

Centre for Archaeological Science, School of Earth &Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Sulawesi is the largest and oldest island within Wallacea, a vast zone of oceanic islands separating continental Asia from the Pleistocene landmass of Australia and Papua (Sahul). By one million years ago an unknown hominin lineage had colonized Flores immediately to the south, and by about 50 thousand years ago, modern humans (Homo sapiens) had crossed to Sahul. On the basis of position, oceanic currents and biogeographical context, Sulawesi probably played a pivotal part in these dispersals. Uranium-series dating of speleothem deposits associated with rock art in the limestone karst region of Maros in southwest Sulawesi has revealed that humans were living on the island at least 40 thousand years ago (ref. 5). Here we report new excavations at Talepu in the Walanae Basin northeast of Maros, where in situ stone artefacts associated with fossil remains of megafauna (Bubalus sp., Stegodon and Celebochoerus) have been recovered from stratified deposits that accumulated from before 200 thousand years ago until about 100 thousand years ago. Our findings suggest that Sulawesi, like Flores, was host to a long-established population of archaic hominins, the ancestral origins and taxonomic status of which remain elusive.
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http://dx.doi.org/10.1038/nature16448DOI Listing
January 2016

The archaeology, chronology and stratigraphy of Madjedbebe (Malakunanja II): A site in northern Australia with early occupation.

J Hum Evol 2015 Jun 7;83:46-64. Epub 2015 May 7.

School of Social Science, The University of Queensland, Brisbane, Qld 4072, Australia.

Published ages of >50 ka for occupation at Madjedbebe (Malakunanja II) in Australia's north have kept the site prominent in discussions about the colonisation of Sahul. The site also contains one of the largest stone artefact assemblages in Sahul for this early period. However, the stone artefacts and other important archaeological components of the site have never been described in detail, leading to persistent doubts about its stratigraphic integrity. We report on our analysis of the stone artefacts and faunal and other materials recovered during the 1989 excavations, as well as the stratigraphy and depositional history recorded by the original excavators. We demonstrate that the technology and raw materials of the early assemblage are distinctive from those in the overlying layers. Silcrete and quartzite artefacts are common in the early assemblage, which also includes edge-ground axe fragments and ground haematite. The lower flaked stone assemblage is distinctive, comprising a mix of long convergent flakes, some radial flakes with faceted platforms, and many small thin silcrete flakes that we interpret as thinning flakes. Residue and use-wear analysis indicate occasional grinding of haematite and woodworking, as well as frequent abrading of platform edges on thinning flakes. We conclude that previous claims of extensive displacement of artefacts and post-depositional disturbance may have been overstated. The stone artefacts and stratigraphic details support previous claims for human occupation 50-60 ka and show that human occupation during this time differed from later periods. We discuss the implications of these new data for understanding the first human colonisation of Sahul.
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http://dx.doi.org/10.1016/j.jhevol.2015.03.014DOI Listing
June 2015

Dating techniques: Illuminating the past.

Nature 2015 Apr;520(7548):438-9

Department of Geography and the Environment, University of the Fraser Valley, Abbotsford, British Columbia V2S 7M8, Canada.

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http://dx.doi.org/10.1038/520438aDOI Listing
April 2015

Research and rural; EGPRN and EURIPA—finding common ground. October 2013, Malta.

Eur J Gen Pract 2015 Mar 20;21(1):77-81. Epub 2014 Nov 20.

University of Wisconsin School of Medicine & Public Health , Wisconsin , USA.

The European General Practice Research Network (EGPRN) and the European Rural and Isolated Practitioner Association (EURIPA) convened a historic joint meeting in Malta in October 2013. Speakers reviewed the inadequacies of the current system and conduct of clinical science research and the use and misuse of the resulting findings. Rural communities offer extraordinary opportunities to conduct more holistic, integrative, and relevant research using new methods and data sources. Investigators presented exciting research findings on questions important to the health of those in rural areas. Participants discussed several strategies to enhance the capacity and stature of rural health research and practice. EGPRN and EURIPA pledged to work together to develop rural research courses, joint research projects, and a European Rural Research Agenda based on the most urgent priorities and the European definition of general practice research in rural health care.
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http://dx.doi.org/10.3109/13814788.2014.936006DOI Listing
March 2015

Continuity of mammalian fauna over the last 200,000 y in the Indian subcontinent.

Proc Natl Acad Sci U S A 2014 Apr 7;111(16):5848-53. Epub 2014 Apr 7.

Research Laboratory for Archaeology and the History of Art, School of Archaeology, University of Oxford, Oxford OX1 3QY, United Kingdom.

Mammalian extinction worldwide during the Late Pleistocene has been a major focus for Quaternary biochronology and paleoecology. These extinctions have been variably attributed to the impacts of climate change and human interference. However, until relatively recently, research has been largely restricted to the Americas, Europe, and Australasia. We present the oldest Middle-Late Pleistocene stratified and numerically dated faunal succession for the Indian subcontinent from the Billasurgam cave complex. Our data demonstrate continuity of 20 of 21 identified mammalian taxa from at least 100,000 y ago to the present, and in some cases up to 200,000 y ago. Comparison of this fossil record to contemporary faunal ranges indicates some geographical redistribution of mammalian taxa within India. We suggest that, although local extirpations occurred, the majority of taxa survived or adapted to substantial ecological pressures in fragmented habitats. Comparison of the Indian record with faunal records from Southeast and Southwest Asia demonstrates the importance of interconnected mosaic habitats to long-term faunal persistence across the Asian tropics. The data presented here have implications for mammalian conservation in India today, where increasing ecological circumscription may leave certain taxa increasingly endangered in the most densely populated region of the world.
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http://dx.doi.org/10.1073/pnas.1323465111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4000863PMC
April 2014

Fifty thousand years of Arctic vegetation and megafaunal diet.

Nature 2014 Feb;506(7486):47-51

1] Laboratoire d'Ecologie Alpine (LECA) CNRS UMR 5553, University Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France [2].

Although it is generally agreed that the Arctic flora is among the youngest and least diverse on Earth, the processes that shaped it are poorly understood. Here we present 50 thousand years (kyr) of Arctic vegetation history, derived from the first large-scale ancient DNA metabarcoding study of circumpolar plant diversity. For this interval we also explore nematode diversity as a proxy for modelling vegetation cover and soil quality, and diets of herbivorous megafaunal mammals, many of which became extinct around 10 kyr bp (before present). For much of the period investigated, Arctic vegetation consisted of dry steppe-tundra dominated by forbs (non-graminoid herbaceous vascular plants). During the Last Glacial Maximum (25-15 kyr bp), diversity declined markedly, although forbs remained dominant. Much changed after 10 kyr bp, with the appearance of moist tundra dominated by woody plants and graminoids. Our analyses indicate that both graminoids and forbs would have featured in megafaunal diets. As such, our findings question the predominance of a Late Quaternary graminoid-dominated Arctic mammoth steppe.
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http://dx.doi.org/10.1038/nature12921DOI Listing
February 2014

Ecology. A pardon for the dingo.

Science 2014 Jan;343(6167):142-3

Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.

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http://dx.doi.org/10.1126/science.1248646DOI Listing
January 2014

The chronostratigraphy of the Haua Fteah cave (Cyrenaica, northeast Libya).

J Hum Evol 2014 Jan 12;66:39-63. Epub 2013 Dec 12.

McDonald Institute for Archaeological Research, University of Cambridge, Cambridge CB2 3ER, UK. Electronic address:

The 1950s excavations by Charles McBurney in the Haua Fteah, a large karstic cave on the coast of northeast Libya, revealed a deep sequence of human occupation. Most subsequent research on North African prehistory refers to his discoveries and interpretations, but the chronology of its archaeological and geological sequences has been based on very early age determinations. This paper reports on the initial results of a comprehensive multi-method dating program undertaken as part of new work at the site, involving radiocarbon dating of charcoal, land snails and marine shell, cryptotephra investigations, optically stimulated luminescence (OSL) dating of sediments, and electron spin resonance (ESR) dating of tooth enamel. The dating samples were collected from the newly exposed and cleaned faces of the upper 7.5 m of the ∼14.0 m-deep McBurney trench, which contain six of the seven major cultural phases that he identified. Despite problems of sediment transport and reworking, using a Bayesian statistical model the new dating program establishes a robust framework for the five major lithostratigraphic units identified in the stratigraphic succession, and for the major cultural units. The age of two anatomically modern human mandibles found by McBurney in Layer XXXIII near the base of his Levalloiso-Mousterian phase can now be estimated to between 73 and 65 ka (thousands of years ago) at the 95.4% confidence level, within Marine Isotope Stage (MIS) 4. McBurney's Layer XXV, associated with Upper Palaeolithic Dabban blade industries, has a clear stratigraphic relationship with Campanian Ignimbrite tephra. Microlithic Oranian technologies developed following the climax of the Last Glacial Maximum and the more microlithic Capsian in the Younger Dryas. Neolithic pottery and perhaps domestic livestock were used in the cave from the mid Holocene but there is no certain evidence for plant cultivation until the Graeco-Roman period.
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http://dx.doi.org/10.1016/j.jhevol.2013.10.001DOI Listing
January 2014

Michael John Morwood (1950-2013).

Nature 2013 Aug;500(7463):401

Centre for Archaeological Science, University of Wollongong, Australia.

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http://dx.doi.org/10.1038/500401aDOI Listing
August 2013

Beyond the Levant: first evidence of a pre-pottery Neolithic incursion into the Nefud Desert, Saudi Arabia.

PLoS One 2013 19;8(7):e68061. Epub 2013 Jul 19.

CNRS, Maison de l'Orient et de la Méditerranée, UMR 5133 Archéorient, Lyon, France.

Pre-Pottery Neolithic assemblages are best known from the fertile areas of the Mediterranean Levant. The archaeological site of Jebel Qattar 101 (JQ-101), at Jubbah in the southern part of the Nefud Desert of northern Saudi Arabia, contains a large collection of stone tools, adjacent to an Early Holocene palaeolake. The stone tool assemblage contains lithic types, including El-Khiam and Helwan projectile points, which are similar to those recorded in Pre-Pottery Neolithic A and Pre-Pottery Neolithic B assemblages in the Fertile Crescent. Jebel Qattar lies ∼500 kilometres outside the previously identified geographic range of Pre-Pottery Neolithic cultures. Technological analysis of the typologically diagnostic Jebel Qattar 101 projectile points indicates a unique strategy to manufacture the final forms, thereby raising the possibility of either direct migration of Levantine groups or the acculturation of mobile communities in Arabia. The discovery of the Early Holocene site of Jebel Qattar suggests that our view of the geographic distribution and character of Pre-Pottery Neolithic cultures may be in need of revision.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0068061PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3716651PMC
March 2014