Segmental morphometrics of the olive baboon (Papio anubis): a longitudinal study from birth to adulthood

The linear dimensions and inertial characteristics of the body are important in locomotion and they change considerably during the ontogeny of animals, including humans. This longitudinal and ontogenetic study has produced the largest dataset to date of segmental morphometrics in a Catarrhini species, the olive baboon. The objectives of the study were to quantify the changes in body linear and inertial dimensions and to explore their (theoretical) mechanical significance for locomotion. We took full-body measurements of captive individuals at regular intervals. Altogether, 14 females and 16 males were followed over a 7-year period, i.e. from infancy to adulthood. Our results show that individual patterns of growth are very consistent and follow the general growth pattern previously described in olive baboons. Furthermore, we obtained similar growth curve structures for segment lengths and masses, although the respective time scales were slightly different. The most significant changes in body morphometrics occurred during the first 2 years of life and concerned the distal parts of the body. Females and males were similar in size and shape at birth. The rate and duration of growth produced substantial size-related differences throughout ontogeny, while body shapes remained very similar between the sexes. We also observed significant age-related variations in limb composition, with a proximal shift of the centre of mass within the limbs, mainly due to changes in mass distribution and in the length of distal segments. Finally, we observed what we hypothesize to be 'early biomechanical optimization' of the limbs for quadrupedal walking. This is due to a high degree of convergence between the limbs' natural pendular periods in infants, which may facilitate the onset of quadrupedal walking. Furthermore, the mechanical significance of the morphological changes observed in growing baboons may be related to changing functional demands with the onset of autonomous (quadrupedal) locomotion. From a wider perspective, these data provide unique insights into questions surrounding both the processes of locomotor development in primates and how these processes might evolve

Bipédie du babouin olive (Papio anubis) : étude de la cinématique articulaire du membre inférieur au cours de l’ontogenèse

La bipédie habituelle représente un marqueur morpho- logique, fonctionnel et comportemental de la lignée humaine. Tous les primates non-humains (PNHs) pratiquent la bipédie spontanément, cependant son utilisation reste occasionnelle chez ces espèces. L’étude de la bipédie dans un cadre comparatif est donc primordiale pour comprendre notre évolution. Des études ont révélé que la fréquence d’utilisation de la bipédie semble plus importante chez les jeunes. Le sujet abordé ici est de savoir si u..

The gibbon's Achilles tendon revisited: consequences for the evolution of the great apes?

The well-developed Achilles tendon in humans is generally interpreted as an adaptation for mechanical energy storage and reuse during cyclic locomotion. All other extant great apes have a short tendon and long-fibred triceps surae, which is thought to be beneficial for locomotion in a complex arboreal habitat as this morphology enables a large range of motion. Surprisingly, highly arboreal gibbons show a more human-like triceps surae with a long Achilles tendon. Evidence for a spring-like function similar to humans is not conclusive. We revisit and integrate our anatomical and biomechanical data to calculate the energy that can be recovered from the recoiling Achilles tendon during ankle plantar flexion in bipedal gibbons. Only 7.5% of the required external positive work in a stride can come from tendon recoil, yet it is delivered at an instant when the whole-body energy level drops. Consequently, an additional similar amount of mechanical energy must simultaneously dissipate elsewhere in the system. Altogether, this challenges the concept of an energy-saving function in the gibbon's Achilles tendon. Cercopithecids, sister group of the apes, also have a human-like triceps surae. Therefore, a well-developed Achilles tendon, present in the last common 'Cercopithecoidea-Hominoidea' ancestor, seems plausible. If so, the gibbon's anatomy represents an evolutionary relict (no harm-no benefit), and the large Achilles tendon is not the premised key adaptation in humans (although the spring-like function may have further improved during evolution). Moreover, the triceps surae anatomy of extant non-human great apes must be a convergence, related to muscle control and range of motion. This perspective accords with the suggestions put forward in the literature that the last common hominoid ancestor was not necessarily great ape-like, but might have been more similar to the small-bodied catarrhines

Marches bipède et quadrupède du babouin olive (Papio anubis) : activité musculaire comparée et perspectives évolutives

La marche bipède humaine est particulièrement raffinée et efficace. Les primates non-humains (PNHs), quant à eux, utilisent la bipédie occasionnellement au sein d’un répertoire posturo-locomoteur souvent varié. Dans le contexte de l’évolution des modes locomoteurs chez les primates (incluant les hominines), une hypothèse suggère l’existence d’un mécanisme de contrôle basique et similaire en bipédie et en quadrupédie. La tester nécessite une observation directe de l’activité musculaire liée à ..

Middle Paleolithic Lithic Industry from Qaleh Kurd Cave, Qazvin Province,Iran

This paper focuses on the lithic finds from two seasons of excavations at Qaleh Kurd (QK), a cave site inwestern Central Plateau. Through sedimentological studies, Holocene and Pleistocene deposits were identifiedduring the excavations. Analysis of sedimentary context and the spatial distribution of the faunal remains andlithics suggested that the Pleistocene deposits at QK split into three sub-periods. Statistical analysis based on thelithic techno-typology confirmed such suggestion with the lithics featuring Middle Paleolithic (MP) affinities inall phases. The cross-sequence comparisons of QK’s lithics with the Zagros and Central Plateau MP assemblagessuggested stronger affinities of QK with the former. The overall characteristics of the QK tool kit consist of ascraper-rich, flake-base typology, low frequency of denticulate and notch, the abundance of points, applicationof Levallois technique, frequent signs of direct percussion, minimal preparation of platform, and the presence ofintense retouching and rejuvenating the edges

Foot bones

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Bipédies et appuis du pied. Référentiels actuels et nouvelles perspectives paléoanthropologiques

Paris, Expansion Formation et Édition

La marche bipède du babouin olive (Papio anubis)

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Les multiples bipédies.

L'Homme moderne n'est pas le seul primate capable de marcher sur ses deux pieds. Grâce à l'étude de diverses bipédies chez les primates actuels et chez les hominidés fossiles, les paléontologues espèrent obtenir des indices supplémentaires pour construire notre arbre généalogiqu