Handedness in Neandertals from the El Sidrón (Asturias, Spain): Evidence from Instrumental Striations with Ontogenetic Inferences
The developed cognitive capabilities for Homo sapiens seems to be the result of a specialized and lateralized brain, and as a result of this, humans display the highest degree of manual specialization or handedness among the primates. Studies regarding its emergence and distribution within the genus Homo show that handedness is present very early. The mode in which it was articulated and spread across the different species during the course of human evolution could provide information about our own cognitive capacities. Here we report the manual laterality attributed to eleven 49,000 old Neandertal individuals from El Sidrón cave (Spain), through the study of instrumental or cultural striations on the anterior dentition. Our results show a predominant pattern addressed to right-handers. These results fit within the modern human handedness distribution pattern and provide indirect evidence for behavior and brain lateralization on Neandertals. They support the early establishment of handedness in our genus. Moreover, the individual identified as Juvenile 1 (6–8 years old at death), displays the same striation pattern as the adult Neandertals from the sample, and thereby the ontogenic development of manual laterality in that Neandertal population seems to be similar to that of living modern humans” (read more/open access).
***About to read this.
(Open access source: PLoS ONE 8(5): e62797)
- By Denise F. Su (Cleveland Museum of Natural History)“The first members of the human lineage lack many features that distinguish us from other primates. Although it has been a difficult quest, we are closer than ever to knowing the mother of us all.Until recently, the evolutionary events that surrounded the origin of the hominin lineage — which includes modern humans and our fossil relatives — were virtually unknown, and our phylogenetic relationship with living African apes was highly debated. Gorillas and chimpanzees were commonly regarded to be more closely related to each other due to their high degree of morphological and behavioral similarities, such as their shared mode of locomotion — knuckle-walking. But with the advent of molecular studies it has become clear that chimpanzees share a more recent common ancestor with humans, and are thus more closely related to us than they are to gorillas (e.g., Bailey 1993, Wildman et al. 2003). The similarities between the living African apes were thought to have been inherited from a common ancestor (=primitive features), implying that the earliest hominins and our last common ancestor shared with chimpanzees had features that were similar, morphologically and behaviorally, to the living African apes (Lovejoy 2009). With the discoveries of the earliest hominin species discussed below, it is now possible to critically examine these assumptions.
The chimpanzee-human divergence date has been estimated to be between 8 and 5 million years ago (MA) since the 1960s through immunologic and molecular techniques (e.g., Steiper & Young, 2006). Driven largely in part by these new genetic-based hypotheses, there have been intensive efforts by different teams over the last two decades to find and explore sediments that record this crucial time period for which we had virtually no fossil evidence. Their hard work and perseverance led to the discovery of several new genera and species of early hominins that are dated close to the estimated divergence dates for chimpanzees and humans. In 1994, Ardipithecus ramidus (ca. 4.4 Ma) was announced (White et al. 1994, 1995, WoldeGabriel et al. 1994) and soon after, even older hominins were discovered: Orrorin tugenensis (6.0-5.7 Ma, Pickford & Senut 2001, Senut et al. 2001, Sawada et al. 2002), Sahelanthropus tchadensis (7-6 Ma, Brunet et al. 2002, 2005, Vignaud et al. 2002), and Ardipithecus kadabba (5.8-5.2 Ma, Haile-Selassie 2001, Wolde Gabriel et al. 2001)” (read more/open access).
(Open access source: Nature Education Knowledge 4(4):11, 2013)
Just a note on Sahelanthropus tchadensis. (I’m lifting this more or less verbatim from an earlier post I wrote because this article cites an article that I think is problematic.)
The difficulty with interpreting TM 266 is that it’s fairly heavily distorted. Zollikofer et al. (2005) attempted to reconstruct/3D model S. tchadensis without the distortion and in this reconstruction (which the article rather uncritically cites) the position of the foramen magnum, the length of the nucal plane and the foramen magnum-orbital plane angle, when taken on their own, are all suggestive of obligate bipedalism . On further inspection, though, it’s pretty apparent that something is wrong: the angle between the orbital plane and the foramen magnum is about 90 degrees, indicating an upright posture greater than even that of the australopithecines. Highly unusual.
Investigating this anomaly further, Wolpoff et al. (2006) conducted a (very convincing, in my opinion) biomechanical assessment of the reconstructed skull and found that it could not have functioned in a vertical posture because of the length of the nuchal plane and vertical height of inion: the nuchal plane is exceptionally long and even with the greatly reduced nuchal angle of the reconstruction, and its most posterior extent is significantly above the Frankfurt Horizontal. The cranial rear and posterior portion of the cranial base (its size, shape, and orientation of the nuchal plane) of TM 266 reflects nuchal functions similar to those of apes. In essence, all these things are compatible with a chimpanzee mode of locomotion.
Unlike australopithecines, the evidence indicates that Salehanthropus was not bipedal.This on its own contrasts with all known hominids, and even in the absence of postcranial remains (though there is potentially a femur associated with Toumai) this anatomy is sufficient to exclude Sahelanthropus from the human clade as it is currently understood. This compatible with genetic estimates of the chimpanzee/hominid divergence.
So, at least in my somewhat-educated opinion, TM 266 is more closely related to apes than hominids. I imagine that the femur, if it is ever formally described, will probably tell a similar story.
4,400-year-old “royal” skeleton unearthed near historic European town
The discovery of the 4,400-year-old burial site of a woman adorned with gold jewellery has prompted speculation that Windsor’s royal connection goes back further than suspected. Archaeologists working in a quarry near the royal family’s Berkshire residence have unearthed a rare Copper Age grave of a middle-aged woman buried with some of Britain’s oldest gold ornaments.
- by Timothy M. Ryan and Colin N. Shaw
“Most analyses of trabecular microarchitecture in mammals have focused on the functional significance of interspecific variation, but they have not effectively considered the influence of body size or phylogeny on bone architecture. The goals of this study were to determine the relationship between trabecular bone and body size in the humeral and femoral heads of extant primates, and to assess the influence of phylogeny on bone microstructure. Using a sample of 235 individuals from 34 primate species, ranging in body size from 0.06 to 130 kg, the relationships between trabecular bone structure and body size were assessed by using conventional and phylogenetic regression analyses. Bone volume fraction, trabecular thickness and trabecular spacing increase with body size, whereas bone surface-area-to-volume ratio decreases. Shape variables such as trabecular number, connectivity density and degree of anisotropy scale inversely with size. Most of these variables scale with significant negative allometry, except bone surface-area-to-volume ratio, which scales with slight positive allometry. Phylogenetic regressions indicate a relatively weak phylogenetic signal in some trabecular bone variables. These data demonstrate that, relative to body size, large primates have thinner and more tightly packed trabeculae than small primates. The relatively thin trabeculae in large primates and other mammals, coupled with constraints on trabecular thickness related to osteocyte function, suggest that increased skeletal loads in the postcranial joints of large mammals are probably mitigated not only through alterations in trabecular microarchitecture, but also through other mechanisms such as changes in cortical bone distribution, limb posture and gait speed” (read more/open access).
(Source: Proceedings of the Royal Society B, 2013 280, 20130172, 2013)
Two examples of prehistoric rock art, images taken from Prehistoric Art by Paul Bahn, 1998
A tiny woman and two children were laid to rest on a bed of flowers 5,000 years ago in what is now the barren Sahara Desert.
Researchers discovered the slender arms of the youngsters still extended to the woman in a perpetual embrace.
The remarkable cemetery is providing clues to two civilisations who lived there, a thousand years apart, when the region was moist and green.
Paul Sereno of the University of Chicago and colleagues were searching for the remains of dinosaurs in the African country of Niger when they came across the startling find.
Some 200 graves of humans were found during fieldwork at the site in 2005 and 2006, as well as remains of animals, large fish and crocodiles.
‘Everywhere you turned, there were bones belonging to animals that don’t live in the desert,’ said Sereno.
‘I realized we were in the green Sahara.’
The graveyard, uncovered by hot desert winds, is near what would have been a lake at the time people lived there. It’s in a region called Gobero, hidden away in Niger’s forbidding Tenere Desert, known to Tuareg nomads as a ‘desert within a desert.’
The human remains dated from two distinct populations that lived there during wet times, with a dry period in between. … Read more.
Symbiosis ; Land of Neanderthals (short 3’ clip)
- Y.N Productions
- Written and directed by R. Hope
- 52’ for Montagne TV (spring 2013).
“We venture on a trail into our distant past, asking; who were the Neanderthals?
The answer, in part, lies entangled in the ancient hinterlands of Neanderthal territories. In those territories numerous caves conceal Neanderthal debris, including their discarded flint tools. Petrological analysis of those flints fingerprints the provenance sites of these tools to specific outcrops within the landscape. Through this, we now understand where Neanderthal went through the land…
Rob Hope follows the trail in a quest to understanding these enigmatic nomads… and meets with specialists J P Raynal, M H Moncel, Camille Daujeard and J Combier of France’s CNRS research department, as well as Svante Pääbo, of the Max Planck Institute and A Defleur.”
What about it?