Publications by authors named "David R Braun"

41 Publications

New hominin remains and revised context from the earliest Homo erectus locality in East Turkana, Kenya.

Nat Commun 2021 04 13;12(1):1939. Epub 2021 Apr 13.

Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Utrecht, Netherlands.

The KNM-ER 2598 occipital is among the oldest fossils attributed to Homo erectus but questions have been raised about whether it may derive from a younger horizon. Here we report on efforts to relocate the KNM-ER 2598 locality and investigate its paleontological and geological context. Although located in a different East Turkana collection area (Area 13) than initially reported, the locality is stratigraphically positioned below the KBS Tuff and the outcrops show no evidence of deflation of a younger unit, supporting an age of >1.855 Ma. Newly recovered faunal material consists primarily of C grazers, further confirmed by enamel isotope data. A hominin proximal 3rd metatarsal and partial ilium were discovered <50 m from the reconstructed location where KNM-ER 2598 was originally found but these cannot be associated directly with the occipital. The postcrania are consistent with fossil Homo and may represent the earliest postcrania attributable to Homo erectus.
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http://dx.doi.org/10.1038/s41467-021-22208-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8044126PMC
April 2021

Ecosystem engineering in the Quaternary of the West Coast of South Africa.

Evol Anthropol 2021 Jan 18;30(1):50-62. Epub 2021 Feb 18.

Department of Archaeology, University of Cape Town, Cape Town, South Africa.

Despite advances in our understanding of the geographic and temporal scope of the Paleolithic record, we know remarkably little about the evolutionary and ecological consequences of changes in human behavior. Recent inquiries suggest that human evolution reflects a long history of interconnections between the behavior of humans and their surrounding ecosystems (e.g., niche construction). Developing expectations to identify such phenomena is remarkably difficult because it requires understanding the multi-generational impacts of changes in behavior. These long-term dynamics require insights into the emergent phenomena that alter selective pressures over longer time periods which are not possible to observe, and are also not intuitive based on observations derived from ethnographic time scales. Generative models show promise for probing these potentially unexpected consequences of human-environment interaction. Changes in the uses of landscapes may have long term implications for the environments that hominins occupied. We explore other potential proxies of behavior and examine how modeling may provide expectations for a variety of phenomena.
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http://dx.doi.org/10.1002/evan.21886DOI Listing
January 2021

Drinking water salinity is associated with hypertension and hyperdilute urine among Daasanach pastoralists in Northern Kenya.

Sci Total Environ 2021 May 20;770:144667. Epub 2021 Jan 20.

Department of Evolutionary Anthropology, Duke University, Durham, NC, United States of America; Global Health Institute, Duke University, Durham, NC, United States of America.

Water salinity is a growing global environmental health concern. However, little is known about the relation between water salinity and chronic health outcomes in non-coastal, lean populations. Daasanach pastoralists living in northern Kenya traditionally rely on milk, yet are experiencing socioecological changes and have expressed concerns about the saltiness of their drinking water. Therefore, this cross-sectional study conducted water quality analyses to examine how water salinity, along with lifestyle factors like milk intake, was associated with hypertension (blood pressure BP ≥140 mm Hg systolic or ≥90 mm Hg diastolic) and hyperdilute urine (urine specific gravity <1.003 g/mL, indicative of altered kidney function). We collected health biomarkers and survey data from 226 non-pregnant adults (46.9% male) aged 18+ from 134 households in 2019 along with participant observations in 2020. The salinity (total concentration of all dissolved salts) of reported drinking water from hand-dug wells in dry river beds, boreholes, and a pond ranged from 120 to 520 mg/L. Water from Lake Turkana and standpipes, which was only periodically used for consumption when no other drinking sources are available, ranged from 1100 to 2300 mg/L. Multiple logistic regression models with standard errors clustered on households indicate that each additional 100 mg/L of drinking water salinity was associated with 45% (95% CI: 1.09-1.93, P = 0.010) increased odds of hypertension and 33% (95% CI: 0.97-1.83, P = 0.075) increased odds of hyperdilute urine adjusted for confounders. Results were robust to multiple specifications of the models and sensitivity analyses. Daily milk consumption was associated with 61-63% (P < 0.01) lower odds of both outcomes. This considerable protective effect of milk intake may be due to the high potassium, magnesium, and calcium contents or the protective lifestyle considerations of moving with livestock. Our study results demonstrate that drinking water salinity may have critical health implications for blood pressure and kidney function even among lean, active pastoralists.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144667DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7969420PMC
May 2021

Operationalizing niche construction theory with stone tools.

Evol Anthropol 2021 Jan 21;30(1):28-39. Epub 2021 Jan 21.

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

One of the greatest difficulties with evolutionary approaches in the study of stone tools (lithics) has been finding a mechanism for tying culture and biology in a way that preserves human agency and operates at scales that are visible in the archaeological record. The concept of niche construction, whereby organisms actively construct their environments and change the conditions for selection, could provide a solution to this problem. In this review, we evaluate the utility of niche construction theory (NCT) for stone tool archaeology. We apply NCT to lithics both as part of the "extended phenotype" and as residuals or precipitates of other niche-constructing activities, suggesting ways in which archaeologists can employ niche construction feedbacks to generate testable hypotheses about stone tool use. Finally, we conclude that, as far as its applicability to lithic archaeology, NCT compares favorably to other prominent evolutionary approaches, such as human behavioral ecology and dual-inheritance theory.
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http://dx.doi.org/10.1002/evan.21881DOI Listing
January 2021

Introduction: Hominin paleobiology in the early Pleistocene Okote Member, Koobi Fora Formation, Kenya.

J Hum Evol 2020 08 25;145:102811. Epub 2020 May 25.

National Museums of Kenya, Nairobi, Kenya; Department of History and Archaeology, University of Nairobi, Kenya.

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http://dx.doi.org/10.1016/j.jhevol.2020.102811DOI Listing
August 2020

Hominin fire use in the Okote member at Koobi Fora, Kenya: New evidence for the old debate.

J Hum Evol 2019 08 16;133:214-229. Epub 2019 Jul 16.

Rutgers, The State University of New Jersey, Anthropology Department, NJ, USA; The National Museums of Kenya, Archaeology Department, Nairobi, Kenya.

Hominin fire use in the early Pleistocene has been debated since the early 1970s when consolidated reddened sediment patches were identified at FxJj20 East and Main, Koobi Fora, Kenya. Since then, researchers have argued for evidence of early Pleistocene fire use at a handful of archaeological sites with evidence of combustion. Some argue that morphological evidence of early Homo erectus fossils indicates a dietary shift to higher quality food sources, which could be achieved by cooking. Others contend that fire use does not become a regular behavior until later, in the middle Pleistocene, when archaeological sites begin to show regular evidence for fire use. An early date for hominin control of fire would help to explain the grade changes seen with the appearance of H. erectus, while a later date would mean that fire would have had little influence on the early development of the lineage. Early hominins would have encountered fire regularly on the landscape, increasing the possibility of hominins interacting with and habituating to natural landscape fire. Only a detailed understanding of the patterns of controlled and natural fires can lead to understanding of early hominin fire use. We present new work on the evidence of fire at the FxJj20 Site complex in Koobi Fora, dated to 1.5 Ma. We highlight evidence of burning found on site through Fourier Transform Infrared spectrometry, and describe ongoing work to investigate the association of hominin behavior and fire evidence. We present data supporting the hypothesis that the site is undisturbed and discuss spatial relationships showing burned material associated with non-burned material. We present data on a type of stone fragment, the Thermal Curve Fragment (TCF), which is indicative of knapped material being exposed to high heat. Finally, we suggest future directions on the topic of fire in the early Pleistocene.
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http://dx.doi.org/10.1016/j.jhevol.2019.01.010DOI Listing
August 2019

Comparative isotopic evidence from East Turkana supports a dietary shift within the genus Homo.

Nat Ecol Evol 2019 07 17;3(7):1048-1056. Epub 2019 Jun 17.

Gorongosa National Park, Sofala, Mozambique.

It has been suggested that a shift in diet is one of the key adaptations that distinguishes the genus Homo from earlier hominins, but recent stable isotopic analyses of fossils attributed to Homo in the Turkana Basin show an increase in the consumption of C resources circa 1.65 million years ago, significantly after the earliest evidence for Homo in the eastern African fossil record. These data are consistent with ingesting more C plants, more animal tissues of C herbivores, or both, but it is also possible that this change reflects factors unrelated to changes in the palaeobiology of the genus Homo. Here we use new and published carbon and oxygen isotopic data (n = 999) taken from large-bodied fossil mammals, and pedogenic carbonates in fossil soils, from East Turkana in northern Kenya to investigate the context of this change in the isotope signal within Homo. By targeting taxa and temporal intervals unrepresented or undersampled in previous analyses, we were able to conduct the first comprehensive analysis of the ecological context of hominin diet at East Turkana during a period crucial for detecting any dietary and related behavioural differences between early Homo (H. habilis and/or H. rudolfensis) and Homo erectus. Our analyses suggest that the genus Homo underwent a dietary shift (as indicated by δC and δO values) that is (1) unrelated to changes in the East Turkana vegetation community and (2) unlike patterns found in other East Turkana large mammals, including Paranthropus and Theropithecus. These data suggest that within the Turkana Basin a dietary shift occurred well after we see the first evidence of early Homo in the region.
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http://dx.doi.org/10.1038/s41559-019-0916-0DOI Listing
July 2019

Earliest known Oldowan artifacts at >2.58 Ma from Ledi-Geraru, Ethiopia, highlight early technological diversity.

Proc Natl Acad Sci U S A 2019 06 3;116(24):11712-11717. Epub 2019 Jun 3.

Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287.

The manufacture of flaked stone artifacts represents a major milestone in the technology of the human lineage. Although the earliest production of primitive stone tools, predating the genus and emphasizing percussive activities, has been reported at 3.3 million years ago (Ma) from Lomekwi, Kenya, the systematic production of sharp-edged stone tools is unknown before the 2.58-2.55 Ma Oldowan assemblages from Gona, Ethiopia. The organized production of Oldowan stone artifacts is part of a suite of characteristics that is often associated with the adaptive grade shift linked to the genus Recent discoveries from Ledi-Geraru (LG), Ethiopia, place the first occurrence of ∼250 thousand years earlier than the Oldowan at Gona. Here, we describe a substantial assemblage of systematically flaked stone tools excavated in situ from a stratigraphically constrained context [Bokol Dora 1, (BD 1) hereafter] at LG bracketed between 2.61 and 2.58 Ma. Although perhaps more primitive in some respects, quantitative analysis suggests the BD 1 assemblage fits more closely with the variability previously described for the Oldowan than with the earlier Lomekwian or with stone tools produced by modern nonhuman primates. These differences suggest that hominin technology is distinctly different from generalized tool use that may be a shared feature of much of the primate lineage. The BD 1 assemblage, near the origin of our genus, provides a link between behavioral adaptations-in the form of flaked stone artifacts-and the biological evolution of our ancestors.
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http://dx.doi.org/10.1073/pnas.1820177116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6575601PMC
June 2019

A missing piece of the Papio puzzle: Gorongosa baboon phenostructure and intrageneric relationships.

J Hum Evol 2019 05 5;130:1-20. Epub 2019 Mar 5.

ICArEHB - Interdisciplinary Center for Archaeology and Evolution of Human Behaviour, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Primate Models for Behavioural Evolution Lab, Institute of Cognitive and Evolutionary Anthropology, School of Anthropology and Museum Ethnography, University of Oxford, UK; Gorongosa National Park, Sofala, Mozambique; Centre for Functional Ecology, Coimbra University, Portugal.

Most authors recognize six baboon species: hamadryas (Papio hamadryas), Guinea (Papio papio), olive (Papio anubis), yellow (Papio cynocephalus), chacma (Papio ursinus), and Kinda (Papio kindae). However, there is still debate regarding the taxonomic status, phylogenetic relationships, and the amount of gene flow occurring between species. Here, we present ongoing research on baboon morphological diversity in Gorongosa National Park (GNP), located in central Mozambique, south of the Zambezi River, at the southern end of the East African Rift System. The park exhibits outstanding ecological diversity and hosts more than 200 baboon troops. Gorongosa National Park baboons have previously been classified as chacma baboons (P. ursinus). In accordance with this, two mtDNA samples from the park have been placed in the same mtDNA clade as the northern chacma baboons. However, GNP baboons exhibit morphological features common in yellow baboons (e.g., yellow fur color), suggesting that parapatric gene flow between chacma and yellow baboons might have occurred in the past or could be ongoing. We investigated the phenostructure of the Gorongosa baboons using two approaches: 1) description of external phenotypic features, such as coloration and body size, and 2) 3D geometric morphometric analysis of 43 craniofacial landmarks on 11 specimens from Gorongosa compared to a pan-African sample of 352 baboons. The results show that Gorongosa baboons exhibit a mosaic of features shared with southern P. cynocephalus and P. ursinus griseipes. The GNP baboon phenotype fits within a geographic clinal pattern of replacing allotaxa. We put forward the hypothesis of either past and/or ongoing hybridization between the gray-footed chacma and southern yellow baboons in Gorongosa or an isolation-by-distance scenario in which the GNP baboons are geographically and morphologically intermediate. These two scenarios are not mutually exclusive. We highlight the potential of baboons as a useful model to understand speciation and hybridization in early human evolution.
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http://dx.doi.org/10.1016/j.jhevol.2019.01.007DOI Listing
May 2019

Author Correction: Two million years of flaking stone and the evolutionary efficiency of stone tool technology.

Nat Ecol Evol 2019 02;3(2):312-316

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

In the version of this Article originally published, the authors mistakenly included duplicate entries in the flake datasets for the new Pech de l'Azé IV and Warwasi collections, resulting in minor errors in the statistical analysis. The authors have now repeated this analysis with the correct flake datasets. As a result, in the following two sentences, the number of flakes has been changed from 19,000 to 18,000: "Using more than 18,000 flakes from 81 assemblages spanning two million years..." and "We applied a comparative approach...on more that 18,000 complete and unmodified flakes." In addition, in Figs. 1-3 and Supplementary Fig. 1, some of the data points for the Pech de l'Azé IV and Warwasi collections have moved; the original and corrected figures are below. Supplementary Tables 1 and 2 have been updated to reflect the corrected statistics, and datasets 'Flake_data' and 'Summary_data' have been replaced with the corrected data files. Furthermore, the data availability statement has been updated with the text "Open access to these data and the R code generated for this study is provided at https://zenodo.org/record/1408081#.W6iyn84zaHs ". The authors would like to thank L. Premo at Washington State University for finding the duplicate entries in the published flake dataset.
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http://dx.doi.org/10.1038/s41559-018-0789-7DOI Listing
February 2019

Cross-sectional properties of the humeral diaphysis of Paranthropus boisei: Implications for upper limb function.

J Hum Evol 2019 01 12;126:51-70. Epub 2018 Dec 12.

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Germany; Division of Anthropology, American Museum of Natural History, USA.

A ∼1.52 Ma adult upper limb skeleton of Paranthropus boisei (KNM-ER 47000) recovered from the Koobi Fora Formation, Kenya (FwJj14E, Area 1A) includes most of the distal half of a right humerus (designated KNM-ER 47000B). Natural transverse fractures through the diaphysis of KNM-ER 470000B provide unobstructed views of cortical bone at two sections typically used for analyzing cross-sectional properties of hominids (i.e., 35% and 50% of humerus length from the distal end). Here we assess cross-sectional properties of KNM-ER 47000B and two other P. boisei humeri (OH 80-10, KNM-ER 739). Cross-sectional properties for P. boisei associated with bending/torsional strength (section moduli) and relative cortical thickness (%CA; percent cortical area) are compared to those reported for nonhuman hominids, AL 288-1 (Australopithecus afarensis), and multiple species of fossil and modern Homo. Polar section moduli (Z) are assessed relative to a mechanically relevant measure of body size (i.e., the product of mass [M] and humerus length [HL]). At both diaphyseal sections, P. boisei exhibits %CA that is high among extant hominids (both human and nonhuman) and similar to that observed among specimens of Pleistocene Homo. High values for Z relative to size (M × HL) indicate that P. boisei had humeral bending strength greater than that of modern humans and Neanderthals and similar to that of great apes, A. afarensis, and Homo habilis. Such high humeral strength is consistent with other skeletal features of P. boisei (reviewed here) that suggest routine use of powerful upper limbs for arboreal climbing.
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http://dx.doi.org/10.1016/j.jhevol.2018.05.002DOI Listing
January 2019

Humeral anatomy of the KNM-ER 47000 upper limb skeleton from Ileret, Kenya: Implications for taxonomic identification.

J Hum Evol 2019 01 7;126:24-38. Epub 2018 Dec 7.

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Germany; Division of Anthropology, American Museum of Natural History, USA.

KNM-ER 47000 is a fossil hominin upper limb skeleton from the Koobi Fora Formation, Kenya (FwJj14E, Area 1A) that includes portions of the scapula, humerus, ulna, and hand. Dated to ∼1.52 Ma, the skeleton could potentially belong to one of multiple hominin species that have been documented in the Turkana Basin during this time, including Homo habilis, Homo erectus, and Paranthropus boisei. Although the skeleton lacks associated craniodental material, the partial humerus (described here) preserves anatomical regions (i.e., distal diaphysis, elbow joint) that are informative for taxonomic identification among early Pleistocene hominins. In this study, we analyze distal diaphyseal morphology and the shape of the elbow region to determine whether KNM-ER 47000 can be confidently attributed to a particular species. The morphology of the KNM-ER 47000 humerus (designated KNM-ER 47000B) is compared to that of other early Pleistocene hominin fossil humeri via the application of multivariate ordination techniques to both two-dimensional landmark data (diaphysis) and scale-free linear shape data (elbow). Distance metrics reflecting shape dissimilarity between KNM-ER 47000B and other fossils (and species average shapes) are assessed in the context of intraspecific variation within modern hominid species (Homo sapiens, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus). Our comparative analyses strongly support attribution of KNM-ER 47000 to P. boisei. Compared to four other partial skeletons that have (justifiably or not) been attributed to P. boisei, KNM-ER 47000 provides the most complete picture of upper limb anatomy in a single individual. The taxonomic identification of KNM-ER 47000 makes the skeleton an important resource for testing future hypotheses related to P. boisei upper limb function and the taxonomy of isolated early Pleistocene hominin remains.
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http://dx.doi.org/10.1016/j.jhevol.2018.06.011DOI Listing
January 2019

Scapular anatomy of Paranthropus boisei from Ileret, Kenya.

J Hum Evol 2018 12;125:181-192

Division of Anthropology, American Museum of Natural History, NY, USA; Humboldt Foundation Fellow at Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Germany.

KNM-ER 47000A is a new 1.52 Ma hominin scapular fossil belonging to an associated partial skeleton from the Koobi Fora Formation, Kenya (FwJj14E, Area 1A). This fossil effectively doubles the record of Early Pleistocene scapulae from East Africa, with KNM-WT 15000 (early African Homo erectus) preserving the only other known scapula to date. KNM-ER 47000A consists of a complete glenoid cavity preserving a portion of the scapular spine and neck, the proximal half of the acromion, and a majority of the axillary border. A sufficient amount of anatomy is preserved to compare KNM-ER 47000A with scapulae of several Australopithecus species, extinct Homo, and living hominoids. The glenohumeral joint of KNM-ER 47000A is more laterally oriented than those of great apes and Australopithecus, aligning it closely with KNM-WT 15000 and modern humans. While this morphology does not imply a strong commitment to arboreality, its scapular spine is obliquely oriented-as in gorillas and some Australopithecus fossils-particularly when compared to the more horizontal orientation seen in KNM-WT 15000 and modern humans. Such a spine orientation suggests a narrow yet long infraspinous region, a feature that has been attributed to suspensory taxa. Accordingly, the morphology of KNM-ER 47000A presents conflicting behavioral implications. Nonetheless, a multivariate consideration of the available scapular traits aligns KNM-ER 47000A and Australopithecus with great apes, whereas KNM-WT 15000 resembles modern humans. The scapular morphology of KNM-ER 47000A is unique among fossil and extant hominoids and its morphological differences from KNM-WT 15000 strengthen the attribution of KNM-ER 47000 to Paranthropus boisei as opposed to early Homo. As the first evidence of scapular morphology in P. boisei, KNM-ER 47000A provides important new information on variation in hominin shoulder and upper limb anatomy from this critical period of hominin evolutionary history.
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http://dx.doi.org/10.1016/j.jhevol.2017.06.013DOI Listing
December 2018

Site fragmentation, hominin mobility and LCT variability reflected in the early Acheulean record of the Okote Member, at Koobi Fora, Kenya.

J Hum Evol 2018 12 27;125:159-180. Epub 2018 Sep 27.

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany; Department of Archaeology, University of Cape Town, 7700, South Africa.

From its initial appearance at ∼1.7 Ma, the Acheulean was prevalent through a vast chronological span of hominin behavioural evolution that lasted nearly 1.5 million years. The origins and production patterns of large bifacial cutting tools ('LCTs') - the marker of the Acheulean techno-complex - and the systematic changes in this behaviour through time are gaining increasing interest in paleoanthropology. Here we provide a synthesis of early Acheulean LCT variation in a landscape context by analysing assemblages from four different quasi-contemporaneous (∼1.4 Ma) sites from the Koobi Fora Formation. We characterize this variation using both 3D geometric morphometric and descriptive approaches. The expansive lateral exposures of fluvial and lacustrine sediments, as well as the associated tephrostratigraphy of the Koobi Fora Formation provide the landscape context that enables these comparative analyses. Our study demonstrates that when multiple contemporaneous early Acheulean localities are analysed together, a broader picture of LCT variability is elucidated. Four sites at Koobi Fora appear to represent a single system of lithic economy, characterized by a discrete trajectory of changes in LCT size and shape. These sites have ranges of LCT forms which appear to represent different but overlapping stages on a single reduction trajectory. Certain sites exhibit the full reduction trajectory while others exhibit only fragments of this trajectory. Other inter-site lithic proxies further complement these patterns in LCT variability. We explore patterns of site function, mobility and hominin landscape use, all of which may be suggestive of a depth of planning in early Acheulean hominins wherein technological activities were undertaken in substantial anticipation of future needs.
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http://dx.doi.org/10.1016/j.jhevol.2018.07.008DOI Listing
December 2018

Pleistocene animal communities of a 1.5 million-year-old lake margin grassland and their relationship to Homo erectus paleoecology.

J Hum Evol 2018 09 30;122:70-83. Epub 2018 Jun 30.

Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany.

The ecological and selective forces that sparked the emergence of Homo's adaptive strategy remain poorly understood. New fossil and archaeological finds call into question previous interpretations of the grade shift that drove our ancestors' evolutionary split from the australopiths. Furthermore, issues of taphonomy and scale have limited reconstructions of the hominin habitats and faunal communities that define the environmental context of these behavioral changes. The multiple ∼1.5 Ma track surfaces from the Okote Member of the Koobi Fora Formation at East Turkana provide unique windows for examining hominin interactions with the paleoenvironment and associated faunas at high spatiotemporal resolution. These surfaces preserve the tracks of many animals, including cf. Homo erectus. Here, we examine the structure of the animal community that inhabited this landscape, considering effects of preservation bias by comparing the composition of the track assemblage to a skeletal assemblage from the same time and place. We find that the track and skeletal assemblages are similar in their representation of the vertebrate paleocommunity, with comparable levels of taxonomic richness and diversity. Evenness (equitability of the number of individuals per taxon) differs between the two assemblages due to the very different circumstances of body fossil versus track preservation. Both samples represent diverse groups of taxa including numerous water-dependent species, consistent with geological interpretations of the track site environments. Comparisons of these assemblages also show a pattern of non-random hominin association with a marginal lacustrine habitat relative to other vertebrates in the track assemblage. This evidence is consistent with behavior that included access to aquatic foods and possibly hunting by H. erectus in lake margins/edaphic grasslands. Such behaviors may signal the emergence of the adaptative strategies that define our genus.
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http://dx.doi.org/10.1016/j.jhevol.2018.04.014DOI Listing
September 2018

Two million years of flaking stone and the evolutionary efficiency of stone tool technology.

Nat Ecol Evol 2018 04 5;2(4):628-633. Epub 2018 Mar 5.

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

Temporal variability in flaking stone has been used as one of the currencies for hominin behavioural and biological evolution. This variability is usually traced through changes in artefact forms and techniques of production, resulting overall in unilineal and normative models of hominin adaptation. Here, we focus on the fundamental purpose of flaking stone-the production of a sharp working edge-and model this behaviour over evolutionary time to reassess the evolutionary efficiency of stone tool technology. Using more than 19,000 flakes from 81 assemblages spanning two million years, we show that greater production of sharp edges was followed by increased variability in this behaviour. We propose that a diachronic increase in this variability was related to a higher intensity of interrelations between different behaviours involving the use and management of stone resources that gave fitness advantages in particular environmental contexts. The long-term trends identified in this study inform us that the evolutionary efficiency of stone tool technology was not inherently in advanced tool forms and production techniques, but emerged within the contingencies of hominin interaction with local environments.
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http://dx.doi.org/10.1038/s41559-018-0488-4DOI Listing
April 2018

Hominin track assemblages from Okote Member deposits near Ileret, Kenya, and their implications for understanding fossil hominin paleobiology at 1.5 Ma.

J Hum Evol 2017 11 13;112:93-104. Epub 2017 Sep 13.

Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA; Humboldt Foundation Fellow at Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig D-04103, Germany.

Tracks can provide unique, direct records of behaviors of fossil organisms moving across their landscapes millions of years ago. While track discoveries have been rare in the human fossil record, over the last decade our team has uncovered multiple sediment surfaces within the Okote Member of the Koobi Fora Formation near Ileret, Kenya that contain large assemblages of ∼1.5 Ma fossil hominin tracks. Here, we provide detailed information on the context and nature of each of these discoveries, and we outline the specific data that are preserved on the Ileret hominin track surfaces. We analyze previously unpublished data to refine and expand upon earlier hypotheses regarding implications for hominin anatomy and social behavior. While each of the track surfaces discovered at Ileret preserves a different amount of data that must be handled in particular ways, general patterns are evident. Overall, the analyses presented here support earlier interpretations of the ∼1.5 Ma Ileret track assemblages, providing further evidence of large, human-like body sizes and possibly evidence of a group composition that could support the emergence of certain human-like patterns of social behavior. These data, used in concert with other forms of paleontological and archaeological evidence that are deposited on different temporal scales, offer unique windows through which we can broaden our understanding of the paleobiology of hominins living in East Africa at ∼1.5 Ma.
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http://dx.doi.org/10.1016/j.jhevol.2017.08.013DOI Listing
November 2017

A reply to Douze and Delagnes's 'The pattern of emergence of a Middle Stone Age tradition at Gademotta and Kulkuletti (Ethiopia) through convergent tool and point technologies' [J. Hum. Evol. 91 (2016) 93-121].

J Hum Evol 2018 12 13;125:201-206. Epub 2017 Jan 13.

Center for the Advanced Study of Hominid Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20025, USA; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany.

Douze and Delagnes (2016) revisit Middle Stone Age (MSA) lithic assemblages from the Gademotta Formation (Fm.), Ethiopia. Their analysis of selected assemblages from three of the 1972 excavations expands the original typo-technological interpretations by Wendorf and Schild (1974). We particularly welcome their evaluation of our recent inferences about the function of pointed artifacts and technological patterns in the Gademotta Fm. (Sahle et al., 2013, 2014). However, we find several arguments and conclusions in Douze and Delagnes (2016) to be rather unconvincing and irreconcilable with results from analyses of whole assemblages (Wendorf and Schild, 1974; Sahle et al., 2013, 2014). Specifically, their summary attribution of all early MSA burin-like fractures on the distal tips of pointed artifacts to intentional resharpening blows, and their use of this pattern as a technological "chrono-marker" unique to the region are untenable. Here, we highlight these issues in the hopes of a clearer understanding of the evident technological patterns in the Gademotta Fm.
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http://dx.doi.org/10.1016/j.jhevol.2016.10.005DOI Listing
December 2018

Footprints reveal direct evidence of group behavior and locomotion in Homo erectus.

Sci Rep 2016 07 12;6:28766. Epub 2016 Jul 12.

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany.

Bipedalism is a defining feature of the human lineage. Despite evidence that walking on two feet dates back 6-7 Ma, reconstructing hominin gait evolution is complicated by a sparse fossil record and challenges in inferring biomechanical patterns from isolated and fragmentary bones. Similarly, patterns of social behavior that distinguish modern humans from other living primates likely played significant roles in our evolution, but it is exceedingly difficult to understand the social behaviors of fossil hominins directly from fossil data. Footprints preserve direct records of gait biomechanics and behavior but they have been rare in the early human fossil record. Here we present analyses of an unprecedented discovery of 1.5-million-year-old footprint assemblages, produced by 20+ Homo erectus individuals. These footprints provide the oldest direct evidence for modern human-like weight transfer and confirm the presence of an energy-saving longitudinally arched foot in H. erectus. Further, print size analyses suggest that these H. erectus individuals lived and moved in cooperative multi-male groups, offering direct evidence consistent with human-like social behaviors in H. erectus.
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http://dx.doi.org/10.1038/srep28766DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4941528PMC
July 2016

Cut marks on bone surfaces: influences on variation in the form of traces of ancient behaviour.

Interface Focus 2016 Jun;6(3):20160006

Department of Human Evolution , Max Planck Institute for Evolutionary Anthropology , Leipzig , Germany.

Although we know that our lineage has been producing sharp-edged tools for over 2.6 Myr, our knowledge of what they were doing with these tools is far less complete. Studies of these sharp-edged stone tools show that they were most probably used as cutting implements. However, the only substantial evidence of this is the presence of cut marks on the bones of animals found in association with stone tools in ancient deposits. Numerous studies have aimed to quantify the frequency and placement of these marks. At present there is little consensus on the meaning of these marks and how the frequency relates to specific behaviours in the past. Here we investigate the possibility that mechanical properties associated with edges of stone tools as well as the properties of bones themselves may contribute to the overall morphology of these marks and ultimately their placement in the archaeological record. Standardized tests of rock mechanics (Young's modulus and Vickers hardness) indicate that the hardness of tool edges significantly affects cut-mark morphology. In addition, we show that indentation hardness of bones also impacts the overall morphology of cut marks. Our results show that rock type and bone portions influence the shape and prevalence of cut marks on animal bones.
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http://dx.doi.org/10.1098/rsfs.2016.0006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4843629PMC
June 2016

Pleistocene footprints show intensive use of lake margin habitats by Homo erectus groups.

Sci Rep 2016 05 20;6:26374. Epub 2016 May 20.

Division of Anthropology, American Museum of Natural History, New York, New York 10024, USA.

Reconstructing hominin paleoecology is critical for understanding our ancestors' diets, social organizations and interactions with other animals. Most paleoecological models lack fine-scale resolution due to fossil hominin scarcity and the time-averaged accumulation of faunal assemblages. Here we present data from 481 fossil tracks from northwestern Kenya, including 97 hominin footprints attributed to Homo erectus. These tracks are found in multiple sedimentary layers spanning approximately 20 thousand years. Taphonomic experiments show that each of these trackways represents minutes to no more than a few days in the lives of the individuals moving across these paleolandscapes. The geology and associated vertebrate fauna place these tracks in a deltaic setting, near a lakeshore bordered by open grasslands. Hominin footprints are disproportionately abundant in this lake margin environment, relative to hominin skeletal fossil frequency in the same deposits. Accounting for preservation bias, this abundance of hominin footprints indicates repeated use of lakeshore habitats by Homo erectus. Clusters of very large prints moving in the same direction further suggest these hominins traversed this lakeshore in multi-male groups. Such reliance on near water environments, and possibly aquatic-linked foods, may have influenced hominin foraging behavior and migratory routes across and out of Africa.
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http://dx.doi.org/10.1038/srep26374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873780PMC
May 2016

Edge Length and Surface Area of a Blank: Experimental Assessment of Measures, Size Predictions and Utility.

PLoS One 2015 2;10(9):e0133984. Epub 2015 Sep 2.

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

Blank size and form represent one of the main sources of variation in lithic assemblages. They reflect economic properties of blanks and factors such as efficiency and use life. These properties require reliable measures of size, namely edge length and surface area. These measures, however, are not easily captured with calipers. Most attempts to quantify these features employ estimates; however, the efficacy of these estimations for measuring critical features such as blank surface area and edge length has never been properly evaluated. In addition, these parameters are even more difficult to acquire for retouched implements as their original size and hence indication of their previous utility have been lost. It has been suggested, in controlled experimental conditions, that two platform variables, platform thickness and exterior platform angle, are crucial in determining blank size and shape meaning that knappers can control the interaction between size and efficiency by selecting specific core angles and controlling where fracture is initiated. The robustness of these models has rarely been tested and confirmed in context other than controlled experiments. In this paper, we evaluate which currently employed caliper measurement methods result in the highest accuracy of size estimations of blanks, and we evaluate how platform variables can be used to indirectly infer aspects of size on retouched artifacts. Furthermore, we investigate measures of different platform management strategies that control the shape and size of artifacts. To investigate these questions, we created an experimental lithic assemblage, we digitized images to calculate 2D surface area and edge length, which are used as a point of comparison for the caliper measurements and additional analyses. The analysis of aspects of size determinations and the utility of blanks contributes to our understanding of the technological strategies of prehistoric knappers and what economic decisions they made during process of blank production.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0133984PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4557928PMC
May 2016

Documenting Differences between Early Stone Age Flake Production Systems: An Experimental Model and Archaeological Verification.

PLoS One 2015 25;10(6):e0130732. Epub 2015 Jun 25.

Department of Archaeology, University of Cape Town, Rondebosch, Western Cape, South Africa.

This study investigates morphological differences between flakes produced via "core and flake" technologies and those resulting from bifacial shaping strategies. We investigate systematic variation between two technological groups of flakes using experimentally produced assemblages, and then apply the experimental model to the Cutting 10 Mid -Pleistocene archaeological collection from Elandsfontein, South Africa. We argue that a specific set of independent variables--and their interactions--including external platform angle, platform depth, measures of thickness variance and flake curvature should distinguish between these two technological groups. The role of these variables in technological group separation was further investigated using the Generalized Linear Model as well as Linear Discriminant Analysis. The Discriminant model was used to classify archaeological flakes from the Cutting 10 locality in terms of their probability of association, within either experimentally developed technological group. The results indicate that the selected independent variables play a central role in separating core and flake from bifacial technologies. Thickness evenness and curvature had the greatest effect sizes in both the Generalized Linear and Discriminant models. Interestingly the interaction between thickness evenness and platform depth was significant and played an important role in influencing technological group membership. The identified interaction emphasizes the complexity in attempting to distinguish flake production strategies based on flake morphological attributes. The results of the discriminant function analysis demonstrate that the majority of flakes at the Cutting 10 locality were not associated with the production of the numerous Large Cutting Tools found at the site, which corresponds with previous suggestions regarding technological behaviors reflected in this assemblage.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0130732PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4482428PMC
April 2016

PALEOANTHROPOLOGY. Response to Comment on "Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia".

Science 2015 Jun;348(6241):1326

School of Human Evolution and Social Change and Institute of Human Origins, Arizona State University, Tempe, AZ 85287, USA.

Hawks et al. argue that our analysis of Australopithecus sediba mandibles is flawed and that specimen LD 350-1 cannot be distinguished from this, or any other, Australopithecus species. Our reexamination of the evidence confirms that LD 350-1 falls outside of the pattern that A. sediba shares with Australopithecus and thus is reasonably assigned to the genus Homo.
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http://dx.doi.org/10.1126/science.aab1122DOI Listing
June 2015

Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia.

Science 2015 Mar 4;347(6228):1352-5. Epub 2015 Mar 4.

Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA.

Our understanding of the origin of the genus Homo has been hampered by a limited fossil record in eastern Africa between 2.0 and 3.0 million years ago (Ma). Here we report the discovery of a partial hominin mandible with teeth from the Ledi-Geraru research area, Afar Regional State, Ethiopia, that establishes the presence of Homo at 2.80 to 2.75 Ma. This specimen combines primitive traits seen in early Australopithecus with derived morphology observed in later Homo, confirming that dentognathic departures from the australopith pattern occurred early in the Homo lineage. The Ledi-Geraru discovery has implications for hypotheses about the timing and place of origin of the genus Homo.
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http://dx.doi.org/10.1126/science.aaa1343DOI Listing
March 2015

Nutrition, modernity and the archaeological record: coastal resources and nutrition among Middle Stone Age hunter-gatherers on the Western Cape coast of South Africa.

J Hum Evol 2014 Dec 16;77:64-73. Epub 2014 Oct 16.

Center for the Advanced Study of Hominid Paleobiology, Department of Anthropology, The George Washington University, 2110 G. St. NW, Washington, DC 20052, United States.

In this paper, we assess the nutritional value of some marine and terrestrial food resources available to Middle Stone Age hunter-gatherers in the Western Cape of South Africa with respect to an important macronutrient (protein) and an essential micronutrient (iron) and introduce a framework for assessing the relative utility of marine and terrestrial resources. Whilst the ability to extract nutrients from the environment has always been a lynchpin in archaeologists' reconstructions of human evolution, a recent paradigm shift has recognized the role of marine resources in encephalization. Nutritional research indicates that marine ecosystems are the best source for long chain polyunsaturated fatty acids essential for proper brain development, and excavations at securely dated archaeological sites in South Africa provide firm evidence for the exploitation of marine resources by Middle Stone Age hunter-gatherers from at least Marine Isotope Stage 5 (130 ka), and possibly even earlier. Because marine molluscs are abundant, predictably located and easily harvested, they would have been readily available to all members of the community, in contrast to terrestrial resources. The improving archaeological record gives important clues to resource choice, but many more nutritional observations are needed to determine the extent to which marine resources could have met the nutrient requirements of prehistoric people. Our observations indicate that marine and terrestrial fauna are both excellent sources of protein, and that marine molluscs have higher iron concentrations than we expected for invertebrate fauna. We calculate the number of individual food items from a selection of marine and terrestrial species needed to provide the protein and iron requirements of a hypothetical group of hunter-gatherers, identify contrasts in peoples' requirements for and access to nutrients and resources, and discuss the implications for prehistoric subsistence strategies and human evolution.
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http://dx.doi.org/10.1016/j.jhevol.2014.02.024DOI Listing
December 2014

Quantifying traces of tool use: a novel morphometric analysis of damage patterns on percussive tools.

PLoS One 2014 21;9(11):e113856. Epub 2014 Nov 21.

Department of Anthropology, Rutgers University, New Brunswick, New Jersey, United States of America; National Museums of Kenya, Nairobi, Kenya.

Percussive technology continues to play an increasingly important role in understanding the evolution of tool use. Comparing the archaeological record with extractive foraging behaviors in nonhuman primates has focused on percussive implements as a key to investigating the origins of lithic technology. Despite this, archaeological approaches towards percussive tools have been obscured by a lack of standardized methodologies. Central to this issue have been the use of qualitative, non-diagnostic techniques to identify percussive tools from archaeological contexts. Here we describe a new morphometric method for distinguishing anthropogenically-generated damage patterns on percussive tools from naturally damaged river cobbles. We employ a geomatic approach through the use of three-dimensional scanning and geographical information systems software to statistically quantify the identification process in percussive technology research. This will strengthen current technological analyses of percussive tools in archaeological frameworks and open new avenues for translating behavioral inferences of early hominins from percussive damage patterns.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0113856PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4240665PMC
December 2015

Old stones' song: use-wear experiments and analysis of the Oldowan quartz and quartzite assemblage from Kanjera South (Kenya).

J Hum Evol 2014 Jul 14;72:10-25. Epub 2014 Apr 14.

Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA; Palaeontology Section, Earth Sciences Department, National Museums of Kenya, Box 40658, Nairobi, Kenya. Electronic address:

Evidence of Oldowan tools by ∼2.6 million years ago (Ma) may signal a major adaptive shift in hominin evolution. While tool-dependent butchery of large mammals was important by at least 2.0 Ma, the use of artifacts for tasks other than faunal processing has been difficult to diagnose. Here we report on use-wear analysis of ∼2.0 Ma quartz and quartzite artifacts from Kanjera South, Kenya. A use-wear framework that links processing of specific materials and tool motions to their resultant use-wear patterns was developed. A blind test was then carried out to assess and improve the efficacy of this experimental use-wear framework, which was then applied to the analysis of 62 Oldowan artifacts from Kanjera South. Use-wear on a total of 23 artifact edges was attributed to the processing of specific materials. Use-wear on seven edges (30%) was attributed to animal tissue processing, corroborating zooarchaeological evidence for butchery at the site. Use-wear on 16 edges (70%) was attributed to the processing of plant tissues, including wood, grit-covered plant tissues that we interpret as underground storage organs (USOs), and stems of grass or sedges. These results expand our knowledge of the suite of behaviours carried out in the vicinity of Kanjera South to include the processing of materials that would be 'invisible' using standard archaeological methods. Wood cutting and scraping may represent the production and/or maintenance of wooden tools. Use-wear related to USO processing extends the archaeological evidence for hominin acquisition and consumption of this resource by over 1.5 Ma. Cutting of grasses, sedges or reeds may be related to a subsistence task (e.g., grass seed harvesting, cutting out papyrus culm for consumption) and/or a non-subsistence related task (e.g., production of 'twine,' simple carrying devices, or bedding). These results highlight the adaptive significance of lithic technology for hominins at Kanjera.
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http://dx.doi.org/10.1016/j.jhevol.2014.03.002DOI Listing
July 2014