Acoustics of the Lascaux cave and its facsimile Lascaux IV.

Access to the original Lascaux cave, a UNESCO World Heritage site famous for its 18 000 year old paintings, has been restricted since 1963. In 2016, an accurate facsimile, Lascaux IV, was designed and built. In the original cave, Lascaux I, classical contemporary room acoustics measurement systems could not be used. However, it has been possible to perform simplified measurements in a few minutes. Similar measurements were made in Lascaux IV once completed. The data provide a unique insight of the acoustic behavior of the Lascaux cave: it shows that the two caves, the original and the copy, have similar acoustical characteristics. In both cases, in the famed Hall of Bulls, the impulse response is smooth, reverberation time is relatively long, and speech intelligibility is fair; this environment is suitable for the ceremonies that presumably took place there. Because of the precision of the copy, Lascaux IV could be used as a 1/1 scale-model of Lascaux I. Therefore, sophisticated acoustical tests could be undertaken in Lascaux IV to help specialists in their archeological investigations. For example, resonances could be precisely documented to explore the potential relationship between parietal painting positions and echoes or sound effects that may have been used in ritual ceremonies.

The genital prolapse of Australopithecus Lucy?

INTRODUCTION AND HYPOTHESIS: The female bony pelvis has to fulfil opposing functions: it has to be sufficiently closed to support the pelvic viscera in the upright position, while remaining sufficiently open to allow vaginal delivery. We aim to give an evolutionary perspective and the possible evolution of the bony pelvis from Lucy to the modern female with the implications in terms of genital prolapse. METHODS: Thirteen pelvimetric measurements were performed on 178 bony pelves: 1 fossil pelvis from Australopithecus Lucy, 128 female Caucasian modern adult pelves and 49 female Catarrhine pelves (29 gorillas and 20 chimpanzees). RESULTS: Lucy's pelvis shape was the most transversely oval, short and broad, termed platypelloid. Modern female pelves were transversely oval only at the inlet. A protruding ischial spine, fairly small ischial tuberosities and a sacral concavity made Lucy closer to Homo sapiens and less like the great apes. In the last group, pelvic planes were anteroposteriorly oval, except in the gorilla, where the outlet was round or slightly transversely oval. The subpubic angle was narrowest in Lucy, whereas it was greater than 90° in the great apes. CONCLUSIONS: The female pelvis is involved in both visceral support and parturition and represents a compromise. The narrower pelvis of Australopithecus Lucy provided protection against genital prolapse, but resulted in complex obstetrical mechanics. From an evolutionary perspective, the pelvis of Homo sapiens became modified to make parturition easier, but increased the risk of genital prolapse: the ilia became wide open laterally and the sacrum broadened with a shorter distance between the sacroiliac and coxofemoral joints.

Unconstrained 3D-kinematics of prehension in five primates: lemur, capuchin, gorilla, chimpanzee, human.

Primates are known for their use of the hand in many activities including food grasping. Yet, most studies concentrate on the type of grip used. Moreover, kinematic studies remain limited to a few investigations of the distal elements in constrained conditions in humans and macaques. In order to improve our understanding of the prehension movement in primates, we analyse here the behavioural strategies (e.g., types of grip, body postures) as well as the 3D kinematics of the whole forelimb and the trunk during the prehension of small static food items in five primate species in unconstrained conditions. All species preferred the quadrupedal posture except lemurs, which used a typical crouched posture. Grasp type differed among species, with smaller animals (capuchins and lemurs) using a whole-hand grip and larger animals (humans, gorillas, chimpanzees) using predominantly a precision grip. Larger animals had lower relative wrist velocities and spent a larger proportion of the movement decelerating. Humans grasped food items with planar motions involving small joint rotations, more similar to the smaller animals than to gorillas and chimpanzees, which used greater rotations of both the shoulder and forearm. In conclusion, the features characterising human food prehension are present in other primates, yet differences exist in joint motions. These results provide a good basis to suggest hypotheses concerning the factors involved in driving the evolution of grasping abilities in primates.

Is the duration of human pregnancy decreasing? A vision of Darwinian medicine.

Why do actual females have a 9-months-pregnancy? Here, we hypothesize that the pregnancies of prehuman species were longer than currently (10 or 11 months), and that anatomical and metabolic changes, by increasing the in-utero size of the fetal brain, selected groups with premature delivery, low-calcified and/or not welded cranial vault bones (permitting deformation during the expulsion), until reaching a current pregnancy duration of 9 months.

Biomechanical study of grasping according to the volume of the object: human versus non-human primates.

The evolution of the precision grips, in which an object is held between the distal surfaces of thumb and fingers and the power grip, in which an object is grasped with the palm, is poorly understood in spite of hypothesis stipulating an evolution from power toward precision grips. In human, numerous studies have shown that the external factors such as the size or the form of an object influenced grasp patterns whereas in non-human primates, those parameters are poorly known. The objective of the present study was to investigate the variation in the use of different grips according to the volume of the object for six primate species representative of the phylogeny: human, chimpanzee, orangutan, macaque, baboon and capuchin. For those species, the grasping patterns were examined during grasping of spherical objects of two different volumes. Frame-by-frame analysis of digit contact strategies indicated: (1) an effect of the species on the category of grasping whatever the volume of the object, (2) a high degree of species variability and (3) no individual difference whatever the species. These results are discussed in relation to its potential contribution to understand the evolution of grasping.

[A biological anthropology of the disappearance of the Neandertal Man: recent data]. / Une anthropologie biologique de la disparition de l'homme de Néandertal : données récentes.

What could have been the causes of the disappearance of Neanderthals? We will try here to make a synthesis between one of the fundamental questions of biological anthropology relating to human evolution (hypotheses on the causes of the extinction of Neanderthals) and evolutionary bio-medical concepts, some of which have recently been reformulated thanks to the progress of paleogenomics (ancestral inheritance of the current human immune system, paleo-microbiology, host-pathogen relationship…).

Mudslide and/or animal attack are more plausible causes and circumstances of death for AL 288 ('Lucy'): A forensic anthropology analysis.

Following a global morphological and micro-CT scan examination of the original and cast of the skeleton of Australopithecus afarensis AL 288 ('Lucy'), Kappelman et al. have recently proposed a diagnosis of a fall from a significant height (a tree) as a cause of her death. According to topographical data from the discovery site, complete re-examination of a high-quality resin cast of the whole skeleton and forensic experience, we propose that the physical process of a vertical deceleration cannot be the only cause for her observed injuries. Two different factors were involved: rolling and multiple impacts in the context of a mudslide and an animal attack with bite marks, multi-focal fractures and violent movement of the body. It is important to consider a differential diagnosis of the observed fossil lesions because environmental factors should not be excluded in this ancient archaeological context as with any modern forensic anthropological case.

[Computed tomography and cranial paleoanthropology]. / Scanner à rayons X et paléoanthropologie crânienne.

Since its invention in 1972, computed tomography (C.T.) has significantly evolved. With the advent of multi-slice detectors (500 times more sensitive than conventional radiography) and high-powered computer programs, medical applications have also improved. CT is now contributing to paleoanthropological research. Its non-destructive nature is the biggest advantage for studying fossil skulls. The second advantage is the possibility of image analysis, storage, and transmission. Potential disadvantages include the possible loss of files and the need to keep up with rapid technological advances. Our experience since the late 1970s, and a recent PhD thesis, led us to describe routine applications of this method. The main contributions of CT to cranial paleoanthropology are five-fold: --Numerical anatomy with rapid acquisition and high spatial resolution (helicoidal and multidetector CT) offering digital storage and stereolithography (3D printing). --Numerical biometry (2D and 3D) can be used to create "normograms" such as the 3D craniofacial reference model used in maxillofacial surgery. --Numerical analysis offers thorough characterization of the specimen and its state of conservation and/or restoration. --From "surrealism" to virtual imaging, anatomical structures can be reconstructed, providing access to hidden or dangerous zones. --The time dimension (4D imaging) confers movement and the possibility for endoscopic simulation and internal navigation (see Iconography). New technical developments will focus on data processing and networking. It remains our duty to deal respectfully with human fossils.

Re-emerging infectious diseases from the past: Hysteria or real risk?

BACKGROUND: Work on human remains and old biological samples is a potential source of contamination by conventional or atypical infectious agents. Similarly, current and future environmental changes are a source of resurgence of ancient epidemic diseases. To what extent are anthropologists sorcerer apprentices (especially those working on ancient samples, i.e. paleo-anthropologists)? Are ancient skeletons, palaeosols and museum objects with a biological component at risk for current populations? Unless there are unfounded fears and undue risk… What can be learned from the recent scientific literature and the common sense of the researchers? METHODS: We have attempted to compile data from the literature and from our personal experience in the fields of anthropology, clinical medicine and epidemiology, in order to grasp the reality of the risk to the human population. RESULTS: It appears that the risk is real, but extremely limited. Specific and simple protective measures must be taken in terms of overall and individual health, both in the field and in the laboratory. CONCLUSION: These data are important for the internist, due to the possibility of atypical infections, both in specialized workers and in populations at risk (environmental context).

Early modern humans and morphological variation in Southeast Asia: fossil evidence from Tam Pa Ling, Laos.

Little is known about the timing of modern human emergence and occupation in Eastern Eurasia. However a rapid migration out of Africa into Southeast Asia by at least 60 ka is supported by archaeological, paleogenetic and paleoanthropological data. Recent discoveries in Laos, a modern human cranium (TPL1) from Tam Pa Ling's cave, provided the first evidence for the presence of early modern humans in mainland Southeast Asia by 63-46 ka. In the current study, a complete human mandible representing a second individual, TPL 2, is described using discrete traits and geometric morphometrics with an emphasis on determining its population affinity. The TPL2 mandible has a chin and other discrete traits consistent with early modern humans, but it retains a robust lateral corpus and internal corporal morphology typical of archaic humans across the Old World. The mosaic morphology of TPL2 and the fully modern human morphology of TPL1 suggest that a large range of morphological variation was present in early modern human populations residing in the eastern Eurasia by MIS 3.

Anthracothere dental anatomy reveals a late Miocene Chado-Libyan bioprovince.

Recent discovery of an abundant and diverse late Miocene fauna at Toros-Ménalla (Chad, central Africa) by the Mission Paléoanthropologique Franco-Tchadienne provides a unique opportunity to examine African faunal and hominid evolution relative to the early phases of the Saharan arid belt. This study presents evidence from an African Miocene anthracotheriid Libycosaurus, particularly well documented at Toros-Ménalla. Its remains reveal a large semiaquatic mammal that evolved an autapomorphic upper fifth premolar (extremely rare in Cenozoic mammals). The extra tooth appeared approximately 12 million years ago, probably in a small northern African population isolated by climate-driven fragmentation and alteration of the environments inhabited by these anthracotheriids [Flower, B. P. & Kennett, J. P. (1994) Palaeogeogr. Palaeoclimatol. Palaeoecol. 108, 537-555 and Zachos, J., Pagani, M., Sloan, L., Thomas, E. & Billups, K. (2001) Science 292, 686-693]. The semiaquatic niche of Libycosaurus, combined with the distribution and relationships of its late Miocene species, indicates that by the end of the Miocene, wet environments connected the Lake Chad Basin to the Libyan Sirt Basin, across what is now the Sahara desert.

Discovery of a second human molar and cranium fragment in the late Middle to Late Pleistocene cave of Ma U'Oi (Northern Vietnam).

In November 2002, during the second season of work by a Vietnamese-French-Japanese team, we discovered a human molar and a fragment of an occipital bone in the late Middle to Late Pleistocene cave of Ma U'Oi (Bacon et al., Geobios. 37 (2004) 305). The layer from which this material comes is the same as that in which a human lower molar was found in 2001. Both molars can be attributed to archaic Homo, and both exhibit archaic and modern traits.

Hominid cranium from Omo: Description and taxonomy of Omo-323-1976-896.

Omo-323-1976-896, a partial hominid cranium dated to ca. 2.1 from the Member G, Unit G-8 of the Shungura Formation, lower Omo Basin of Ethiopia, is described. It is suggested that the specimen is an adult male based on the well-developed and completely fused sagittal crest; heavily worn teeth; relatively large canine; and size of the articular eminence. Omo-323 consists of fragments of the frontal, both temporals, occipital, parietals, and the right maxilla, and is attributed to Australopithecus boisei, making it the oldest known cranium of this species. The specimen shares features with Australopithecus aethiopicus (KNM-WT 17000), thus supporting the existence of an evolving East African robust lineage between ca. 2.6-1.2 Ma. The morphology of Omo-323 increases our knowledge of the intraspecific variability of A.boisei.

A new hominid from the Upper Miocene of Chad, Central Africa.

The search for the earliest fossil evidence of the human lineage has been concentrated in East Africa. Here we report the discovery of six hominid specimens from Chad, central Africa, 2,500 km from the East African Rift Valley. The fossils include a nearly complete cranium and fragmentary lower jaws. The associated fauna suggest the fossils are between 6 and 7 million years old. The fossils display a unique mosaic of primitive and derived characters, and constitute a new genus and species of hominid. The distance from the Rift Valley, and the great antiquity of the fossils, suggest that the earliest members of the hominid clade were more widely distributed than has been thought, and that the divergence between the human and chimpanzee lineages was earlier than indicated by most molecular studies.