The upper limb of Paranthropus boisei from Ileret, Kenya

Anatomy, Archaeology, Archeology, Evolution, Geology, Human Evolution, Human Origins, Journal of Human Evolution, Lithic Analysis, Lithics, Palaeoanthropology, Palaeobiology, Palaeontology, Paleobiology, Paleontology

Figure 3. Stratigraphic section (left) shown with the image (right) of the outcrop highlighting the positions of the three major tuffs. All hominin fossils were found on the surface or in secondarily deposited sediment below the Ileret Tuff (1.52 ± 0.01 Ma). Some of the remains were found above the Lower Ileret Tuff (1.53 ± 0.01 Ma) indicating that the bones must have been buried above it. The large excavation area is visible on the right side of the outcrop and gully; the lower footprint level (Bennett et al., 2009Dingwall et al., 2013Hatala et al., 2017) is exposed on the left side of the image. All fragments of KNM-ER 47000 were located on the surface of the lower portion of the outcrop or secondarily buried in sediment eroded from the drainage that extends up the slope from the excavation site toward the right margin of the picture.

Paranthropus boisei was first described in 1959 based on fossils from the Olduvai Gorge and now includes many fossils from Ethiopia to Malawi. Knowledge about its postcranial anatomy has remained elusive because, until recently, no postcranial remains could be reliably attributed to this taxon. Here, we report the first associated hand and upper limb skeleton (KNM-ER 47000) of P. boisei from 1.51 to 1.53 Ma sediments at Ileret, Kenya. While the fossils show a combination of primitive and derived traits, the overall anatomy is characterised by primitive traits that resemble those found in Australopithecus, including an oblique scapular spine, relatively long and curved ulna, lack of third metacarpal styloid process, gracile thumb metacarpal, and curved manual phalanges. Very thick cortical bone throughout the upper limb shows that P. boisei had great upper limb strength, supporting hypotheses that this species spent time climbing trees, although probably to a lesser extent than earlier australopiths. Hand anatomy shows that P. boisei, like earlier australopiths, was capable of the manual dexterity needed to create and use stone tools, but lacked the robust thumb of Homo erectus, which arguably reflects adaptations to the intensification of precision grips and tool use. KNM-ER 47000 provides conclusive evidence that early Pleistocene hominins diverged in postcranial and craniodental anatomy, supporting hypotheses of competitive displacement among these contemporaneous hominins.

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Figure 1. Right upper limbs of a modern human (left), chimpanzee (center), and KNM-ER 47000 (right), which preserves lateral portions of the scapula, the distal portion of the humerus, most of the ulna, and most of metacarpals (MCs) 1-3 and proximal phalanges 2-4. KNM-ER 47000 has primitive traits including a gracile thumb MC, lack of MC 3 styloid process, curved phalanges with prominent flexor sheaths, a long and curved ulna, a humerus with thick cortical bone and a prominent brachioradialis flange, and obliquely oriented scapular spine. Derived traits include a relatively long thumb, short manual phalanges, and a lateral scapular glenoid orientation. Scale bar at right is 10 cm.

Dating the skull from Broken Hill, Zambia, and its position in human evolution

Archaeology, Archeology, Human Evolution
Extended Data Fig. 1 | Photos of the skull shortly after its discovery. a, The cranium at the location in which it was found.
© Illustrated London News Ltd/Mary Evans. b, c, Frontal view (b) and lateral view (c) before the matrix was removed.
Images from the Archive of the Natural History Museum.

The cranium from Broken Hill (Kabwe) was recovered from cave deposits in 1921, during metal ore mining in what is now Zambia. It is one of the best-preserved skulls of a fossil hominin, and was initially designated as the type specimen of Homo rhodesiensis, but recently it has often been included in the taxon Homo heidelbergensis. However, the original site has since been completely quarried away, and—although the cranium is often estimated to be around 500 thousand years old—its unsystematic recovery impedes its accurate dating and placement in human evolution. Here we carried out analyses directly on the skull and found a best age estimate of 299 ± 25 thousand years (mean ± 2σ). The result suggests that later Middle Pleistocene Africa contained multiple contemporaneous hominin lineages (that is, Homo sapiensH. heidelbergensis/H. rhodesiensis and Homo naledi), similar to Eurasia, where Homo neanderthalensis, the Denisovans, Homo floresiensisHomo luzonensis and perhaps also Homo heidelbergensis and Homo erectus were found contemporaneously. The age estimate also raises further questions about the mode of evolution of H. sapiens in Africa and whether H. heidelbergensis/H. rhodesiensis was a direct ancestor of our species

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A descriptive and comparative study of two Early Pleistocene immature scapulae from the TD6.2 level of the Gran Dolina cave site (Sierra de Atapuerca, Spain)

Human Evolution

Here we present the descriptive and comparative study of two immature scapulae recovered from the TD6.2 level of the Gran Dolina cave site (Sierra de Atapuerca, Spain) and assigned to Homo antecessor. This is the first time that data on the morphology and dimensions of the scapulae of a European late Early Pleistocene hominin population are provided. Considering the state of development and the linear dimensions, the scapula ATD6-116 could belong to a child of about 2–4 years. The morphology of ATD6-116 clearly departs from that of the Australopithecus afarensis juvenile specimen DIK-1-1, pointing to functional differences in locomotor behavior between Australopithecus and the late Early Pleistocene hominins. The immature scapula ATD6-118 belonged to an immature individual with a development of the scapula equivalent to that of adolescents of recent human populations. The scapulae ATD6-118 and KNM-WT 15000 present a similar state of development. Although the scapula KNM-WT 15000 is clearly larger than ATD6-118, these two specimens share some characteristics such as their relative narrowness and the value of the axilloglenoid and spinoglenoid angles. The glenoid fossa of ATD6-116 show a lateral orientation, whereas in ATD6-118 the glenoid fossa is slightly cranially oriented, but still within the range of variation of modern humans. The glenoid index of both ATD6-116 and ATD6-118 is low in accordance to the values usually observed in other early hominins, thus showing the primitive condition for this feature. Both scapulae show a ventrally placed axillary sulcus. The presence of this primitive feature in ATD-116 confirms that the shape of the axillary border has a genetic basis and it is not related to physical activity.

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Asymmetrical Palaeolithic wooden spear tips: Expediency or design?

Human Evolution

Palaeolithic wooden spears provide rare but unique insights into early hunting technology. Examples from Schöningen, Germany indicate that spear tips were sometimes asymmetrical. This asymmetry has previously been interpreted as evidence for planning depth. A more parsimonious explanation, however, is that asymmetrical tips could be more efficiently produced (i.e., took less time to make) than symmetrical ones. Here, we experimentally investigated two different manufacturing processes, producing asymmetrical and symmetrical spear tips, while also testing the influence of biometric factors on spear-tip manufacturing efficiency (measured by time). One group of experimental participants sliced the wooden stave into an asymmetrical shape (slicing on one side of the stave with a steel blade), while the other group created a symmetrical shape (slicing on multiple sides of the stave). Based on time taken, results demonstrated no significant difference in efficiency between symmetrical and asymmetrical spear-tip manufacture. Conversely, some biometric characteristics (specifically pinch strength) present a more dominant influence in explaining time variation. These results demonstrate that the asymmetrical tips at Schöningen were not merely a byproduct of maximizing efficiency during the manufacturing process, but rather are evidence of planning and the associated cognitive capacities of these later Middle Pleistocene hominins.

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Pre-Acheulean industry dating at Dungo IV site at Baia Farta, Benguela, Angola

Human Evolution

Along the Angolan coast, the Early Paleolithic sites of Dungo IV and V (Baia Farta, Benguela) have delivered a rich pre-Acheulean lithic industry testifying the antiquity of the hominin settlement in western Africa despite the current absence of any hominin fossil in the area. In Dungo IV, the Paleolithic level is located on a conglomeratic paleo-beach (104 m a.s.l.) buried under an at least 3 m thick sandy layer. In Dungo V, two unearthed large whale fossils are associated with numerous lithic tools intimately mixed with the whale bones. This is the oldest evidence of stranded marine mammal scavenging by hominins in this part of Africa. The lack of volcanism and fossils makes chronological constrain difficult. Considering its configuration, the Dungo IV site may be relevant for a dating based on both the 10Be and 26Al cosmogenic nuclides. For this purpose, a depth profile all along the sandy layer overlying the archeological layer has been sampled. Statistical treatments performed on the 26Al/10Be ratios obtained for the depth profile demonstrate that they all belong to the same population. If we consider that the samples have always been at or close to their sampling depth, the regression modeling allows computing that the surface sedimentary layer has been emplaced at least 614 ka ago and less than 662 ka ago. On the other hand, if we consider that the surface deposit has been truncated, burial durations ranging from 585 ka to 786 ka and truncations lower than 4 m result from the modeling of the evolution of the 10Be and 26Al concentrations as a function of depth.

The analyses of four pre-Acheulean artefacts lead to a minimum burial duration of 730 ka and a maximum burial duration of 2.11 Ma.

The low pre-burial denudation rates modeled from the data acquired for the stone tools as well as for the overlying layer (1–16 m.Ma−1) imply large inherited 26Al and 10Be concentrations. The post-depositional maximum denudation rate of 71 m.Ma−1associated with both the lithic artefacts and the surface sedimentary layer (considering that the samples have always been at or close to their sampling depth) as well as the deduced maximum uplift rate of ∼170 m.Ma−1 are in agreement with the known tectonic evolution and the climatic variability of this area.

This study confirms the antiquity of the hominin presence in western Africa more than 2000 km away from the closest old hominin fossil sites.

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Tuff 7 with Australopithecus afarensis footprints formed during four major eruption events

Human Evolution
Fig. 1. Major volcanoes in the Crater Highlands and the Gregory rift – shaded and coloured SRTM elevation model (February 2000). Africa image: coloured SRTM elevation model (February 2000). Courtesy NASA/JPL/NIMA.

The Upper Laetolil marker Tuffs 1 to 8 are mineralogically similar rocks, but heterogeneous in terms of their texture, structure, proportion of primary minerals, volume of cement and degree of low-temperature alteration. Originally they were deposited as crystal and/or vitric ash of evolved melilite-nephelinitic composition and not as melilitite-(natro)carbonatite. Occurrence of carbonate-silicate melt inclusions in primary minerals supports R. Hay’s conclusion that the ash could have erupted from a carbonatitic volcanic source. Primary minerals (melilite, clinopyroxene, garnet, perovskite, magnetite) in the tuffs are characterised by wide variations in their compositions and two and even more mineral populations are present within each marker tuff. Thus, any correlation between the tuffs from different localities on the basis of mineral composition is very difficult to impossible. Tuff 7, with footprints of Australopithecus afarensis, is a very heterogeneous unit both vertically and laterally that formed during four major eruption events. Trace-element geochemistry and Sr–Nd isotopic data for Tuffs 6, 7 and 8 suggest that compositionally different volcanic sources were involved in their formation. Initial 87Sr/86Sr and 144Nd/143Nd ratios also show that the Sadiman volcano should not be considered as a source for these three marker tuffs at Laetoli. Only Essimingor and Mosonik volcanoes produced rocks that are mineralogically and geochemically similar to the Upper Laetolil marker tuffs, though these volcanoes lie about 100 km from Laetoli.

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New dating is provided for the Neanderthal site of Carihuela Cave

Human Evolution
Fig. 6. Position of the samples for 230Th
234U determination (Table 6) in CIII AE section 1 (unit VI).

Hitherto unpublished 14C and 230Th 234U determinations from Carihuela Cave (Granada province, Andalusia, Spain) raise a possibility of late survival here of Neanderthals and their Mousterian technocomplex into an advanced stage of the Late Pleistocene (MIS-3), when anatomically-modern humans with Upper Palaeolithic toolkits were penetrating the region, and when also several carnivore taxa competed for access to the cave. Previous palaeopalynological studies are reinforced by new pollen analyses of samples extracted from coprolites. The palaeoecological and sedimentological records bear comparison with new data from the Padul peat deposits in the Sierra Nevada, and are in line with the view that there was late persistence of the Mousterian in Granada. There is a pressing need for renewed international multidisciplinary research at Carihuela Cave, with up-to-date lithostratigraphical and dating techniques that can expand on results obtained from fieldwork undertaken by a previous generation of researchers. Carihuela Cave continues to hold out great promise for analysing Neanderthal palaeoecology during the Late Pleistocene up to the appearance in southeastern Iberian Peninsula of anatomically-modern Upper Palaeolithic people, particularly with regard to the earlier phases of the Middle Palaeolithic at the cave which await intensive excavation but apparently extend back in time to the last interglacial period.

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Early Upper Paleolithic subsistence in the Levant: Zooarchaeology of the Ahmarian–Aurignacian sequence at Manot Cave, Israel

Human Evolution
Figure 1. (a) Location of Manot Cave and other sites mentioned in the text; (b) Plan of the cave showing the location of Area C, with the sample squares highlighted red. Area D is the hyena den deposits; (c) The studied profile.

The Early Upper Paleolithic period in the Levant is essential in the studies of the establishment of modern human communities outside Africa, and corresponding archaeological evidence may be used to shed light on human ecology, economy and demography. Specifically, cultural differences between two Early Upper Paleolithic entities, the Early Ahmarian and the Levantine Aurignacian, raise the question of differing adaptations. In this article we use archaeofaunal remains from the Early Upper Paleolithic sequence at Manot Cave (Western Galilee, Israel), to track human hunting patterns, carcass transport and processing within the Early Ahmarian (46–42 ka) and Levantine Aurignacian (38–34 ka) phases. We test two hypotheses: 1) the Ahmarian and Aurignacian represent adaptations to different environments; and 2) the two entities differ in mobility patterns and site use.

Our multivariate taphonomic analysis showed subtle differences in depositional processes between the two phases and demonstrated a primarily anthropogenic complex. In both phases, human subsistence was based on two ungulate species, mountain gazelle (Gazella gazella) and Mesopotamian fallow deer (Dama mesopotamica), with some contribution from birds, tortoises and small mammals. Among the gazelles, it appears that female herds were targeted, and that hunting took place close to the cave. The results of the research show great similarity in environmental exploitation between the Ahmarian and Aurignacian phases concerning prey spectrum and choice, carcass transport and processing. These patterns occupy a middle position between the Middle Paleolithic and the late Epipaleolithic of the region. Despite this, there are also several significant differences between the phases such as increased exploitation of small game (especially birds) and faster accumulation and higher densities of material in the Aurignacian. This may indicate greater occupation intensity during the Aurignacian compared to the Ahmarian, and thus could explain the outstanding character of this entity in the Levant.

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More light shed on use of plants by Homo neanderthalensis

Archaeology, Archeology, Biological Science, Evolution, Human Evolution, Human Origins, Palaeobiology, Paleobiology

The ecology of Neanderthals is a pressing question in the study of hominin evolution. Diet appears to have played a prominent role in their adaptation to Eurasia. Based on isotope and zooarchaeological studies, Neanderthal diet has been reconstructed as heavily meat-based and generally similar across different environments. This image persists, despite recent studies suggesting more plant use and more variation. However, we have only a fragmentary picture of their dietary ecology, and how it may have varied among habitats, because we lack broad and environmentally representative information about their use of plants and other foods. To address the problem, we examined the plant microremains in Neanderthal dental calculus from five archaeological sites representing a variety of environments from the northern Balkans, and the western, central and eastern Mediterranean. The recovered microremains revealed the consumption of a variety of non-animal foods, including starchy plants. Using a modeling approach, we explored the relationships among microremains and environment, while controlling for chronology. In the process, we compared the effectiveness of various diversity metrics and their shortcomings for studying microbotanical remains, which are often morphologically redundant for identification. We developed Minimum Botanical Units as a new way of estimating how many plant types or parts are present in a microbotanical sample. In contrast to some previous work, we found no evidence that plant use is confined to the southern-most areas of Neanderthal distribution. Although interpreting the eco-geographic variation is limited by the incomplete preservation of dietary micro remains, it is clear that plant exploitation was a widespread and deeply rooted Neanderthal subsistence strategy, even if they were predominately game hunters. Given the limited dietary variation across Neanderthal range in time and space in both plant and animal food exploitation, we argue that vegetal consumption was a feature of a generally static dietary niche.

Dental calculus indicates widespread plant use within the stable Neanderthal dietary niche

Robert C. Power, Domingo C. Salazar-García, Mauro Rubini, Andrea Darlas, Katerina Harvati, Michael Walker, Jean-Jacques Hublin, Amanda G.Henry

DOI: 10.1016/j.jhevol.2018.02.009

Hominin Evolution Book Review: Bones of Contention (1987)

Archaeogenetics, Archaeology, Archeogenetics, Archeology, Biological Science, Evolution, Genetics, Human Evolution, Human Origins, Palaeoanthropology, Palaeobiology, Palaeoecology, Palaeontology, Palaeozoology, Paleoanthropology, Paleobiology, Paleoecology, Paleontology, Radiometric Dating, Research, Science, Taxonomy

It has been a while since I posted on my blog and so out of guilt I’m back again to give you all a new post. This time I want to review a book published in 1987 on the political history of Palaeoanthropology. Written by biochemist Roger Lewin (1944 – Present) it charts the history of the science of Palaeoanthropology and is a must read for anyone interested in the origins of the genus Homo. In 1989, Lewin won the Royal Society Prizes for Science Books, for this very work. Many palaeoanthropologists at the top today could use with reading this book, to help them reflect on their own interaction with other workers in the field. The book was later revised in 1997, which at the time of posting was 21 years ago. There is no question that the field in need of an update to see if the field has changed or remained the same. I hope we will see this 3rd edition in the near future. Among other topics there is no doubt that the recent sexual misconduct of some scientists will need to be discussed in that new book. Let’s talk about the book. The title is very appropriate but when I first heard of it many years ago, I couldn’t help but bring out the immature side in me and snigger at the close similarity of the title with “Boners of Contentions”.  I pondered on the potential look of the T-shirt, I could have printed. Anyway, the book covers a number of important moments in palaeoanthropological history.

In no particular order, Lewin discusses the storm surrounding the Taung Child, Ramapithecus, the KBS Tuff, the famous Australopithecus afarensis A.L. 288-1 and finally the work of the Leakey, specifically the father and the son. Here we see human nature at its worst usually, particularly when we get emotionally invested in a fossil or hypothesis or even flawed radiometric dating. Human evolutionary research, whether the workers in the field, like it or not, is storytelling. Storytelling based on evidence, I might add, but it possesses shades of science fiction. The hominin fossil record is extremely fragmentary and the stories told by these fossils are also extremely fragmentary. They are necessarily weak and this is not particularly useful in a field, where the scientists develop emotional attachment to their pet hypotheses. Even in the light of new evidence many still ignore due to the embarrassment of admitting you are wrong, based on the new evidence. In Palaeoanthropology, admitting you were wrong has been virtually impossible. There is really only one recorded case of a straight up “I was wrong and someone else was right”, that honour goes to Arthur Keith and his review of Raymond Darts Taung Child.

The book allows me to reflect on my own strongly held convictions that Homo heidelbergensis is a valid taxon, at a time when palaeoanthropologists generally shy away from using it. I have imbued it with my own emotional attachment and will remain unconvinced that it should be invalidated. But equally, those who argue the latter, are blinded by their own biases. They do forget that the fossil record of the species is incredibly sparse, with only a handful of skulls representing it. Admittedly, they have a point regarding the Mauer Mandible as the holotype of the species. Ideally, the holotype should be a complete skeleton, but the early science of palaeoanthroplogy was not rigorous in how it proposed new species. So, we are stuck with a mandible in a hypodigm entirely of crania, you read right one mandible and a handful of crania. This, I would argue is no grounds to invalidate a species. In debates, the emotional investment, gets in the way of objective thought and they can get quite heated. Thankfully, I’m not the only palaeoanthropology student indulging in Pro-Heidelbergensis camp. In 2017, Roksandic et al., conducted a revision of the representatives of Homo heidelbergensis. Bones of Contention has allowed me to at the very least be aware of my flaws when it comes to interpreting the fossil record, but with the above paragraph, I’ve really only scratched the surface and it will require a separate essay on the topic for the future.

Bones of Contention is a well written book and while it loosely follows event chronologically, Lewin does compare and contrast most of the events, concluding with a theme that binds these momentous events together. The reminder that we are telling stories is the key thought all palaeoanthropologists should be aware of. I’m aware that the latter is quite a risky statement, but in order for the palaeoanthropology student to be as objective as possible, we need to keep reminding ourselves of that. Many at the top, I suspect, will laugh at this as obsurd. One could argue that the science is far more rigorous in every way today than the time Eoanthropus dawsonii was first unveiled to the world. The Humans that study the fossils, well they have not changed. We are still flawed scientists, whether we like to admit it or not. This is uncomfortable for me to say, but it is true. In the early 1900’s, scientists saw hominin evolution as a variation of the chain of being, a line from ancient apes to human’s, today a variation of multiregional evolutionism is the hip new hypothesis with the “river delta” as its logo.

One topic that the book does not cover is the nature of public engagement of palaeoanthropology contrasted with scientific process associated with palaeoanthropology. For me, these are two different worlds, incredibly incompatible and one scoffs at the other in righteous indignation. There will be no way to bridge the gap between the two. Yes, some seem to be bridging this gap, but if you really dig deeper, the reality is very different. Science is an ever shifting process of evidence evaluation, something that is incompatible with the requirement of certainty in the press. I often cringe at the often used phrase that “textbooks will have to be re-written on palaeoanthropology”. This comes as no surprise to any palaeoanthropology student, but this statement implies that palaeoanthropologists had figured out the evolutionary steps hominins took over the past seven million years to get to where we are today. Far from it and this is what angers a lot of palaeoanthropology students and lecturers. The media need a hook and unfortunately the most effective hook to draw the public in is the above statement. You can’t blame them for reaching as wide an audience as possible. But this has meant that palaeoanthropologists in particular are cautious when they engage with the media. The seemingly innocuous move to record conference talks on new scientific findings is very risky from the point of view of the speaker. Choice of words at a presentation on record and the choice of words on the academic paper may be subtly different but they have the potential to ruin the academic standing of the speaker. Additionally, journals have strict embargo rules on when engagement with the media can begin. Break these rules and the paper will never be published. There will remain a tension between these two worlds for many centuries to come. I hope that the 3rd edition of Bones of Contention will cover this in more detail than I have here.

The only criticism I have of the book is the placement of the black and white photographs in the book. It would be more beneficial to have them scattered throughout the book, associated with their appropriate chapters, instead of combining them together  in two groups in the centre of the book. This is not much of a criticism, but it does demonstrate the difficulty I had in my attempt to find one. It is an excellent book. To use a quote from Leonard to Sheldon in the Big Bang Theory, reading this book “is like looking into an obnoxious little mirror”. It help us re-examine ourselves and re-focuses our thoughts on a very controversial science.

quote-probably-the-most-important-skill-that-children-learn-is-how-to-learn-too-often-we-give-roger-lewin-149-71-97