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Dans Growth and Form, D’Arcy Thompson décrit les formes vivantes à l’aide d’une analyse mathématique, jetant les bases de la morphométrie géométrique. Malgré les inévitables passages obsolètes, il s’agit d’un ouvrage majeur et cohérent qui contient une réflexion profonde sur la recherche scientifique impliquant l’unité des sciences.

La forme d’un être vivant traduit les conditions fonctionnelles de sa survie, son écologie, son histoire phylogénétique et les mécanismes responsables de sa construction, son ontogénie. C’est seulement à la lumière de cette triade de recherches qu’on peut espérer comprendre la réalité de toute forme.

Parmi les religions institutionnelles, les formules monotheistes se sont imposees dans le Proche-Orient en association avec l'histoire de societes hierarchisees et leurs modalites d'exercice du pouvoir. Cette relation a fait des religions des agents responsables des plus grands massacres de l'histoire. L'exercice de la raison, du doute et de la cri-tique a conduit au developpement de la philosophie et de la science, souvent en opposition avec les religions. Cepen-dant, d'une part les causes mentales de la tentation du recours a la religion resident en chaque etre humain et se trou-vent renforcees par des conditions sociales, d'autre part la soif de pouvoir et l'instrumentation du fait religieux dressent des obstacles a l'epanouissement de l'humanite. Les solutions resident dans la conjonction d'une diffusion massive des connaissances et un partage volontariste des ressources.

A detailed description of muscular and skeletal features of the pelvi-cloacal region of the amphisbaenian Blanus cinereus reveals that the species has real hind limbs articulating with a real pelvic girdle. Arguments support this homology: 1) a link with the vertebral column; 2) a movable articulation, showing all the features of a diarthrosis, between the femur and the acetabulum; 3) all the long bone characteristics for the femur which distally bears a horny element. The morphological peculiarities of the amphisbaenian pelvic girdle are generally close to those of lizards, but the pubis seems to be more reduced. For the same number of precloacal vertebrae, the amphisbaenians have more appendicular elements than lizards have, and this composition recalls that of the Leptotyphlopidae, Aniliidae, and Boidae. The account provides more information concerning the aponeuro-tendinous system associated to the skeleton of the girdle and the hindlimb, the musculature, and the interrelations between the different structures of the pelvi-cloacal region.

The simultaneous use of electromyography (EMG), strain gauges, and cinematography show that the capacity of continuous displacement from a single peg is based on the following: sequential activity of the tested muscles from front to rear; activity restricted to the short portion of the body in contact with the peg; alternate action of the muscle longissimus dorsi on the two sides, the transition between one side to the other occurring at the site of contact with the peg; unilateral activity of the muscle supracostalis ventralis responsible for a bulging against the peg; a great stability in the direction of the resultant force, which makes only a small angle with the directio of the motion.

International audience; Granitic outcrop vegetation was compared in 22 inselbergs of French Guiana, South America, using RLQ and fourth-corner analyses to identify the main relationships between environmental gradients and plant traits. At the scale of the whole territory the distribution of species and species traits was mostly driven by a spatially-structured gradient embracing regional climate (annual rainfall), forest matrix (canopy openness), and inselberg features (altitude, shape, habitats, summit forest, degree of epiphytism, fire events). Biogeographic, environmental and past historical factors contribute to explain the variation observed at coarse scale and two groups of inselbergs are identified. A first group occupies the southern peneplain in a semi-open forest matrix and exhibits a higher representation of suffrutescent species and climbers, a lower representation of upright shrubs, a lower degree of Guiana Shield endemism, and a higher incidence of human use and autochory. All these features suggest an adaptation to more disturbed environments linked to past climate changes and savannization and to human influences. A second group, characterized by opposite plant traits, occupies the northern part of French Guiana and the far south within a closed forest matrix. Within archipelagos (inselbergs at less than 7 km distance), C-score and Mantel tests revealed a random co-occurrence of plant species and an increase of floristic dissimilarity with distance without any concomitant change in plant traits, respectively, suggesting that spatially-structured stochastic factors (limitation by dispersal) were the driving force of vegetation change at fine scale.

Korzun, Leonid P., Érard, Christian, Gasc, Jean-Pierre, Dzerzhinsky, Felix J. (2009): Adaptation of seedsnipes (Aves, Charadriiformes, Thinocoridae) to browsing: a study of their feeding apparatus. Zoosystema 31 (2): 347-368, DOI: 10.5252/z2009n2a7, URL: http://www.bioone.org/doi/abs/10.5252/z2009n2a7

Many studies of interest in motor behaviour and motor impairment in mice use equally treadmill or track as a routine test. However, the literature in mammals shows a wide difference of results between the kinematics of treadmill and overground locomotion. To study these discrepancies, we analyzed the locomotion of adult SWISS-OF1 mice over a large range of velocities using treadmill and overground track. The use of a high-speed video camera combined with cinefluoroscopic equipment allowed us to quantify in detail the various space and time parameters of limb kinematics. The results show that mice maintain the same gait pattern in both conditions. However, they also demonstrate that during treadmill exercise mice always exhibit higher stride frequency and consequently lower stride length. The relationship of the stance time and the swing time against the stride frequency are still the same in both conditions. We conclude that the conflict related to the discrepancy between the proprioceptive, vestibular, and visual inputs contribute to an increase in the stride frequency during the treadmill locomotion.

Locomotion in terrestrial vertebrates is supposed to be derived from preadaptation in bottom-dwelling fish. A few fish species have been assumed to walk on the substratum, on the basis of coordinated movements of their paired fins. However, the validity of this assumption has remained uncertain, because of a lack of evidence that their fin rays actually exert a force on the substratum. Here, we provide the first conclusive evidence that a benthic teleost fish, the gurnard, Chelidonichthys lucerna (Triglidae), exerts forces on the substratum during its temporary bottom-dwelling hexapod locomotion. This demonstration was achieved by the use of a photoelastic gel technique combined with a force calibration device. The movement patterns of the three first pairs of rays of the pectoral fins were analysed in relation to the forces exerted on the substratum, by measuring deformations of the photoelastic gel substratum produced by the rays. The rays were shown to produce a force pattern that confirmed the existence of a hexapod locomotion in a vertebrate that was consistent with body propulsion and voluntary substratum walking. J. Exp. Zool. 307A:542–547, 2007. © 2007 Wiley-Liss, Inc.

No transformational theory could have been proposed before clear definitions were derived for the concepts of form and function. The maturation of these concepts followed the slow discovery of the rules that underlie the structural and functional basis of living beings. This question raises apparent contradictions that were overcome, but still left some pitfalls for evolutionary biology. The main one is the remnants of teleology in the heart of the adaptation concept, necessary to recognize the effects of natural selection. Functional Morphology has the hard task to navigate through these difficulties. To cite this article: J.-P. Gasc, C. R. Palevol 5 (2006) .

We analysed spatial and temporal characteristics of mouse locomotion and investigated whether mouse gait differed between strains and environments. To this end, we used two inbred strains of mice (BALB/cByJ and C57BL/6J) known for their contrasting inherent level of anxiety, in three different visual surroundings. The animal position was determined relative to each environment. Gait cycle, defined as the sequence of limb movements, was analysed relative to time. We also recorded spatial parameters of gait such as stride length, track width and footfall characteristics. These measures allowed us to obtain an accurate description of locomotion and to assess subtle modifications of the gait. We found that mice adjusted their position in space, posture and gait in order to either stabilize their body on the ground in a potentially unsafe environment, or to optimize propulsion and maneuverability in a safer location. In addition, the two strains of mice used different strategies, suggesting that the inherent level of emotionality may affect the organization of locomotion in mice. We further concluded that higher structures of the central nervous system are involved in the online control of locomotion.

The kinematics of each joint of the guinea pig Cavia porcellus were studied during the locomotor cycle at increasing speed by high-speed cinefluorography. The main objective was to reveal the functional specific features of these structural elements in each dynamic phase of the cycle and also which limb joints are important during the increase of animal speed. Most of the analysed angles in C. porcellus were affected as the speed increased, both in trot and gallop. However, only a few of them were correlated with speed. There were also differences with respect to symmetrical or asymmetrical gaits. Both pairs of limbs responded differently to the increase of speed; while the forelimb joints modified the duration of their action (frequency) more than the amplitude (stride length), the hindlimbs acted inversely. The movements of the joints during the stance phase changed dramatically with speed, particularly in the hindlimb. At knee level, the flexion amplitude increases to maintain the stiffness of the leg spring, a principle previously discussed as essential for the running process. In the swing phase, inertial effects are the main constraints and, as in the stance phase, the knee joint in the swing phase is correlated with speed both during trot and gallop, confirming the major importance of this joint to increasing speed.

This paper suggests three additions to the Hildebrand method for gait-pattern specification. The first allows an extension of this method by the use of the forelimb as reference. Thus, dataset could be gathered indifferently from fore or hindlimbs cycles to identify a symmetrical gait or compare gaits of diverse species. On the basis of Hildebrand's definitions, the second suggestion permits to check the proportion of symmetrical and asymmetrical gaits adopted by different individuals of one or different species. The third addition makes a graphical clear-cut between four basic modes of gallops: rotary, transverse, half-bound and bound. These additions will facilitate extensive data comparison either to evaluate the range of variation within a single species or to specify the preferred gaits in diverse species. To cite this article: S. Renous et al., C. R. Biologies 327 (2004).

Resume L'hoazin demeure l'un des oiseaux actuels les plus enigmatiques. L'analyse morphofonctionnelle de ses appareils du bec et hyoidien permet, non seulement de mieux comprendre les caracteristiques de l'adaptation trophique de cette espece, mais fournit aussi des donnees nouvelles sur sa position systematique. Le crâne et la musculature crânienne, les particularites de la rhamphotheque et du palais, l'appareil hyoidien et sa musculature font ici l'objet d'une description detaillee. Sans toutefois sortir du cadre general d'organisation propre aux Neognathes, a l'exception des Galliformes, la structure des appareils du bec et hyoidien est caracterisee, chez l'hoazin, par une serie de particularites specifiques et uniques chez les oiseaux. Cette espece apparait particulierement bien adaptee au detachement des feuilles et a leur traitement dans le bec avant ingestion. En raison des importantes differences dans la configuration structurale de cet ensemble et des modes de fonctionnement qui en decoulent, tout rapprochement entre l'hoazin et les Galliformes nous parait devoir etre completement ecarte : une telle hypothese impliquerait une reversion evolutive, qui peut etre consideree comme contre-selective. Pour citer cet article : L.P. Korzoun et al., C. R. Biologies 326 (2003).

Fore- and hindlimb muscles were dissected in four species of Lipotyphla: the western European hedgehog Erinaceus europaeus (Erinaceidae, Erinaceinae); the moonrat Echinosorex gymnura (Erinaceidae, Hylomyinae or Galericinae); the tailless tenrec Tenrec ecaudatus (Tenrecidae, Tenrecinae); and the common European white-toothed shrew Crocidura russula (Soricidae, Soricinae). This work completely reviews the limb musculature of these walking mammals. Twelve myological characters were evaluated in order to disclose phylogenetic relationships. The cladogram obtained supported previous ones based on cranial and dental characters. This study shows that myological characters are valuable in phylogenetic analyses. J. Morphol. 252:183–201, 2002. © 2002 Wiley-Liss, Inc.

Seven juvenile individuals of the Australian species Crocodylus johnstoni from the Frankfurt Zoological Park were filmed on high-speed video, at 250 fields s−1, whilst freely moving at various speeds in a long corridor. The sequences of locomotion were analysed to determine the various space and time parameters to characterize limb kinematics. We found that the animals use diverse patterns of asymmetrical gait, revealing great flexibility in limb co-ordination. In all these gaits, the forelimb strikes the ground first, in the couple made by diagonally opposite fore- and hindlimbs. Among these gaits, rotary gallop offers probably a high level of manoeuvrability, whereas transverse gallop resulted in a higher level of stability. Speed increase is achieved by half-bound and bound, the latter being the only gait used at velocities > 2 m s−1. Speed was increased mainly by increasing the stride length of the fore- and hindlimbs by simultaneously increasing both its components, the step and swing lengths. However, in bound, the step length of each forelimb increased more than the swing length, resulting in a stronger thrust action, whereas swing length increased more than step length for the hindlimb, causing the centre of mass to accelerate forwards during its ballistic phase. The asymmetrical gaits of crocodiles such as Crocodylus johnstoni are probably not functionally equivalent to the transitional asymmetrical gaits exhibited by lizards when building up into a bipedal run. These gaits are also not entirely equivalent to mammalian gaits, despite the use of vertical movements of the vertebral axis in these crocodiles, favouring an erect dynamic posture.

The present study points to morpho-anatomical features that allow vegetarian but mainly frugivorous turacos to fill at best their specific feeding requirements. Mechanisms are analysed which the bird can use to detach a fruit and avoid it rolls out of the bill. It is also examined how vegetable items can be processed particularly when they have to be cut, and what can facilitate their ingestion particularly when they are fruits that have to be swallowed entirely and are large and/or have dry or fibrous skin or flesh. The skeletal and muscular anatomy of the bill and hyoid apparatus is described in details and illustrated. The particularly short and stout bill coupled with a relatively simple system of aponevroses of the adductors reflects a trade-off between two important jaw functional requirements: huge efforts for clamping, and a wide opening for plucking, processing and swallowing relatively large fruit. The clearly oblique orientation of the modified outer adductor seems an adaptation to the detachment of fruits. The os uncinatum , particularly developed in this bird family, is interpreted as maintaining transversal stability, particularly when jaws act as a pair of scissors. Most food items being processed near the base of the bill, mechanisms have been developed which contribute to overcome the risk of breakage at the level of the prokinetic hinge because of a vertically oriented force there. Hyoid apparatus features are related to the tongue role during the detachment of the fruit and its processing in the bill.

During forward locomotion, guinea pigs adopted a posture which, although different, was as stereotyped as at rest. The whole extent of the vertebral column was extended, parallel to the earth-horizontal plane. This result supports the hypothesis that, in mammals, gaze and postural control by the central nervous system would be simplified by the adoption of a limited number of skeletal configurations. They would be optimized for energy saving, biomechanical efficacy and limitation of the number of degrees of freedom of the skeletal apparatus. Transition between rest and forward locomotion displayed two prominent characteristics: the head was stabilized versus space throughout the whole transition and the modifications of the skeletal geometry were confined to the median plane and to two major articular regions. Such an organization revealed a fourth characteristic of the guinea pig postural control: the skeletal configurations retained by evolution would ensure that smooth transitions take place between rest and the various activities of its motor repertoire. Finally, our purely descriptive data shed new light on the architecture of the neuronal network which underlies the vestibular control of gaze and posture.

A morphofunctional analysis of the bill apparatus was conducted on some African forest flycatchers (Muscicapidae, Platysteiridae, Monarchidae) in relation to detailed eco-ethological data available on these species. The aim was to evaluate relationships between anatomical structures and habitat constraints and also identify the most pertinent trophic adaptations. If forest Muscicapidae have essentially conserved the generalized passerine structures and occupy open-habitat niches in the forest, Platysteiridae and Monarchidae have adapted to forest conditions and show a key-adaptation based on specific changes in the structure of the bill apparatus in response to particular light patterns and habitat clogginess, constraints that require speed and precision for the capture of prey and protection of the skull against collisions.

Resume Les relations phylogenetiques a l'interieur de la sous-famille des Crotalinae sont inferees par une analyse de parcimonie a partir de sequences d'une portion du gene codant le cytochrome b. Au total, 396 paires de bases ont ete sequencers pour huit especes de Crotalinae (Agkistrodon blomhoffi, Agkistrodon contortrix, Bothriechis schlegelii, Bothriopsis bilineata, Bothrops atrox, Crotalus atrox, Lachesis muta et Trimeresurus stejnegeri) ainsi que pour quatre taxons choisis comme groupes externes (Atractaspis micropholis, Boa constrictor, Cerastes cerastes et Elapsoidea semiannulata). La monophylie des Crotalinae ainsi que celle formee par les genres Atractaspis et Elapsoidea sont confirmees. Au sein des Crotalinae, le genre Agkistrodon est paraphyletique. Le complexe Bothrops n'apparait pas monophyletique, le genre d'Amerique centrale Bothriechis etant groupe frere du genre Crotalus et non des genres sud-americains Bothriopsis et Bothrops.

The striking ability of the polar bear to travel on ice or frozen snow is tentatively related to different structural features involved in the locomotor behaviour of the animal. A comparison with the brown bear shows the specific features, in gaits, leg movement and in ground contact structures. It is suggested that these specific features constitute a functional complex adapted to locomotion in polar environment. During slow gaits, polar bear hind limbs are maximally extended. The legs are able to resist the transfer of mass during the contralateral limb swing phase. This results in a walk with swaying hips. The polar bear uses transverse gallop to improve stability, whereas the brown bear uses rotary gallop. The polar bear is comfortable on slippery wet substrate, while the brown bear is reluctant to move on it. Proximodistal alternation of pads and large zones with hair constitute the main characteristics of the plantar and palmar soles of the polar bear. These features may constitute a functional specialization for the drainage of water from the feet, the reinforcing of adhesion and an increase in the area of contact (snowshoe). The drainage is produced by two kinds of structures: the superficial network of the epidermis of the pads and the hair between the pads. These hirsute zones absorb the liquid which is drained off the pads by the animal's weight during the stance phase. The hairs are also present in the regions of the soles where thrusts are transmitted to the ground.

The fast gait of jirds (Meriones shawi shawi) was analyzed by means of high-speed X-ray cinematographic film (500 frames/s). The gait is asymmetrical, related to the transverse gallop with a cycle duration of 0.15 s, for a speed of 1 m∙s−1. The flight phase, which can last for up to 10% of the cycle duration, follows the takeoff of one anterior limb. The kinematics of the hind limb reveal that the angular excursion of the femur is small, but is increased 100% by dorsiflexion (stance phase) and ventroflexion (swing phase) of the vertebral column. During the propulsive moment, the knee joint is stable while the ankle joint opens quickly to a wide angle (70° in 40 ms). The shank joint and the head oscillate vertically, and the relative movements of the anterior and posterior parts of the body create dynamic effects facilitating the cantilevered position of the forequarters during 35% of the cycle. This kinematic analysis reveals that these small mammals differ from large ones in the way they use the geometry of their limbs even when the limbs are moved in a parasagittal plane during fast running.

The understanding of the adaptive significance of primate locomotor diversity requires studies under naturalistic conditions that combine frequency of use and biomechanical analyses. Here, we report on limb kinematics and gait parameters of the arboreal quadrupedal walk of adult free-ranging red howlers (Alouatta seniculus). The data derive from the analysis of original video recordings shot in a primary rain forest in French Guiana. Diagonal-sequence diagonal-couplets walks largely dominated, with mean speeds of 0.67 ± 0.26 m/s. Stance duration was equal for both limbs. During the forelimb swing phase, arm abduction and protraction and elbow extension were the principal movements. Arm abduction and retraction, progressive elbow extension, and forearm pronation dominated ­during the stance phase. During the swing phase of the hind limb, hip flexion, thigh abduction, and knee extension dominated. Hip extension, thigh abduction, and knee extension were the main movements during the stance phase. These findings appear to support preliminary laboratory observations, provide a background for biomechanical associations, and underline the evolutionary and adaptive importance of morpho-functional complexes within the primate radiation.

The predatory strike of Vipera ammodytes was analysed using high speed cinematography. Slow motion studies showed that the strike is a direct hit and that ensuing body postures are complex and occur within a very short time. Flawed strikes have been recorded and are discussed. Radiographic study of oesophageal deglutition demonstrated a lateral undulation of the cervical column resulting from metachronic contractions of body wall musculature, causing prey progress. Some comparative data on Bitis nasicornis and B.gabonica are given.

Chez sept enfants d'âge compris entre 5 ans 11 mois et 12 ans 5 mois, pris au hasard, ont ete analysees les praxies de deglutition precedant le temps œsophagien. Il a ete procede a un enregistrement radiocinematographique (avec amplification de brillance, a la vitesse de 60 images/sec.). Ont ete analysees les trajectoires de 7 points-reperes et determinees les equations horaires fournissant les vitesses et accelerations crâniennes, mandibulaires et hyoidiennes. Ont ete decrites les excursions et deformations des organes turgescents ou elastiques : voile du palais, langue, paroi posterieure du pharynx et epiglotte. Les analyses radiocinematographique et cinetique conduisent a admettre que le calvarium et la musculature nuchale participent activement a la deglutition (mouvement d'extension cervico-cephalique). En outre, la cinematique mandibulaire et la cinematique linguale sont relativement independantes l'une de l'autre. Enfin, les temps buccal et pharyngien ne se succedent pas mais se chevauchent partiellement ; et c'est pendant l'intervalle de temps ou la fin de la praxie orale et le debut de la praxie pharyngienne se superposent que s'accomplit la praxie isthmique (franchissement de l'isthme du gosier et traversee du carrefour aero-digestif).

Abstract L'étude du squelette d'embryons à terme et de nouveau-nés d'orvet (Anguis fiagilis, L.) et de lézard vert (Lacerta viridis, Laur.) montre une constance dans les rapports entre la scapula et un segment vertébral précis. Ceci conduit à admettre que la 3e vertèbre cervicale de l'orvet est homologue à la 5e vertèbre cervicale du lézard vert. La région cervicale de l'orvet comporterait donc 6 vertèbres et celle du lézard vert, 8. L'étude histologique de jeunes embryons de ces deux espèces suggère que 2 somites supplémentaires prennent part, chez l'orvet, à la formation de la plaque parachordale. Ceci expliquerait la différence de 2 vertèbres trouvée au niveau de la région cervicale. Chez l'orvet, comme chez le lézard vert, le nerf hypoglosse est formé par les 5 racines ventrales des premiers nerfs occipitaux. Chez Lacerta viridis, le premier nerf spinal, qui peut ici être considéré comme un premier nerf cervical, rejoint pour partie l'hypoglosse; par contre, chez Anguis fragilis, ce nerf est incorporé à la région occipitale et gagne seulement la région de l'ébauche du membre antérieur.

We analysed treadmill locomotion of the adult SWISS-OF1 mice over a large range of velocities. The use of a high-speed video camera combined with cinefluoroscopic equipment allowed us to quantify in detail the various space and time parameters of limb kinematics. We find that velocity adjustments depend upon whether animal used a symmetrical or non-symmetrical gait. In symmetrical gaits, the increase of velocity generally results equally from an increase in the stride frequency and the stride length. On the other hand, in non-symmetrical gaits, the increase in velocity is achieved differently according to the level of velocity used. As speed increases, velocity increases first as a consequence of increased stride frequency, then as in symmetrical gaits, by an equal increase in both variables, and finally at high speed, velocity increases through increased stride length. In both symmetrical and non-symmetrical gaits, stance and swing-time shortening contributed to the increase of the stride frequency, with stance time decrease being the major contributor. The pattern of locomotion obtained in the present study may be used as a model mouse system for studying locomotor deficits resulting from specific mutations in the nervous system. To cite this article: M. Herbin et al., C. R. Palevol 5 (2006).

For the present study, 15 species of pigeons representing the 5 sub-families usually recognized, and 3 species of sandgrouse were examined. The skeleton and musculature of the bill and hyoid apparatus are described. Morpho-functional analyses show that from a key adaptation to the removal and deglutition (without processing) of attached plant items, pigeons would have followed two pathways, one based on the joint muscular control of the movement of the jaws (Columbinae, Treroninae, Gourinae), the other on the separate muscular control (Didunculinae, Otidiphabinae). Sandgrouse would have diverged from this latter, developing the ability to very selectively remove attached plant items as well as to peck particularly small seeds on the ground. Unexpected differences appeared between sandgrouse species which raise eco-ethological problems.

The present study compares the forefoot and hindfoot musculature of five representative species of Cavioidea rodents. In all species, the musculature of both forefeet and hindfeet have the same array regardless of the absence of digit I in the manus of Hydrochaeris hydrochaeris and Cavia porcellus. Our results suggest a tendency in these species towards a three-digit system, with a functional loss of digit V and a predominance of digit III in their forefeet. In the same way, the muscular reduction of digit I in the other rodents analyzed indicates a four-digit system with predominance of digit II in Myoprocta acouchy and Dasyprocta leporina and of digit V in Agouti paca. There seems to be an association between the muscular arrangement and functional axis of the foot, raising the general question why this axis runs between the third and forth digit, or along the third digit.

The present study contrasts available biological data and results of morphofunctional analyses of the bill and hyoid apparatus in motmots. It shows that these omnivorous birds, which take relatively large food items, possess osteomuscular peculiarities that enable them to process these items as a whole in order to soften or cut them, and make them suited for easy ingestion. For that, they use the crenate edges of their rhamphotheca. Their jaws work as a highly mobile saw-like system. Their mutual movements, enhanced by the fact that particular dispositions of the hyoid apparatus rise the tongue and the supported items high up into buccal cavity, facilitate an effective clamping of items that can be moved along the jaws and be quite appropriately processed. To cite this article: L.P. Korzun et al., C. R. Biologies 327 (2004).

The gaits of the adult SWISS mice during treadmill locomotion at velocities ranging from 15 to 85 cm s(-1) have been analysed using a high-speed video camera combined with cinefluoroscopic equipment. The sequences of locomotion were analysed to determine the various space and time parameters of limb kinematics. We found that velocity adjustments are accounted for differently by the stride frequency and the stride length if the animal showed a symmetrical or an asymmetrical gait. In symmetrical gaits, the increase of velocity is provided by an equal increase in the stride length and the stride frequency. In asymmetrical gaits, the increase in velocity is mainly assured by an increase in the stride frequency in velocities ranging from 15 to 29 cm s(-1). Above 68 cm s(-1), velocity increase is achieved by stride length increase. In velocities ranging from 29 to 68 cm s(-1), the contribution of both variables is equal as in symmetrical gaits. Both stance time and swing time shortening contributed to the increase of the stride frequency in both gaits, though with a major contribution from stance time decrease. The pattern of locomotion obtained in a normal mouse should be used as a template for studying locomotor control deficits after lesions or in different mutations affecting the nervous system.

The hoatzin remains one of the most enigmatic birds. A morphofunctional analysis of its bill and hyoid apparatus throws new light on its feeding adaptation as well as on its systematic relationships. Bony and muscular skull, rhamphotheca, palate, and hyoid apparatus were described in details. Though keeping into the general organisation pattern found among Neognathae (except Galliformes), bill and hyoid apparatus of the hoatzin displays a series of species-specific features, some unique among birds. This species appears particularly well adapted to tear of leaves and process them inside the bill before ingestion. Because of very important anatomical and thence functional differences in bill and hyoid structure, any close relationship between the hoatzin and Galliformes cannot be envisioned. Such a hypothesis would implicate a counter-selective evolutionary reversion.

Making a quadrupedal robotic machine walk is a problem with an infinity of solutions. Nevertheless, this question seems to have been solved successfully by mammals. Hence a particular approach in the design of walking robots has been considered, based on the animals movement characteristics. Indeed, studying animal walking can help produce a class of solutions towards the definition of quadrupedal robots. From this starting point, a model can be created according to a reduced number of criteria, notably the shape of the trajectory followed by the ankle or wrist during motion relatively to the hip or to the shoulder respectively. The problem lies in the difficulty to extract significant and valuable information from the mere observation of animals walking. This paper presents an experiment designed to extract angular variations data from the observation of a walking hedgehog and the use of these data to create a 2D dynamical simulation model to be used as an analysis basis.

Making a quadrupedal robotic machine walk is a problem with an infinity of solutions. Nevertheless, this question seems to have been solved successfully by mammals. Hence a particular approach in the design of walking robots has been considered, based on the animals movement characteristics. Indeed, studying animal walking can help produce a class of solutions towards the definition of quadrupedal robots. From this starting point, a model can be created according to a reduced number of criteria, notably the shape of the trajectory followed by the ankle or wrist during motion relatively to the hip or shoulder respectively. The problem lies in the difficulty to extract significant and valuable information from the simple observation of animal walking (Taylor, 1950). This paper presents a brief recounting of a method used to extract angular variations data from the observation of a walking hedgehog and the use of these data to create a 2 dimensional dynamical simulation model. This model is then used to produce a first series of simulation experiments.

Kinematics and structural analyses were used as basic data to elaborate a dynamic quadruped model that may represent an unspecialised mammal. Hedgehogs were filmed on a treadmill with a cinefluorographic system providing trajectories of skeletal elements during locomotion. Body parameters such as limb segments mass and length, and segments centre of mass were checked from cadavers. These biological parameters were compiled in order to build a virtual quadruped robot. The robot locomotor behaviour was compared with the actual hedgehog to improve the model and to disclose the necessary changes. Apart from use in robotics, the resulting model may be useful to simulate the locomotion of extinct mammals.

In phylogenetically based systematics, Mammalia is the nomenclatural term which designates the clade stemming from the most recent common ancestry of monotremes and theria [ De Queiroz , Sys. Biol. 43 (1994) 497]. Considering that locomotor performance is a prevalent function to provide the necessary conditions to survive and transmit genes, it may be questioned if the diverse types of locomotion exhibited by extant mammals could have played a role in their evolution, or have only followed it. We may look after the structural and behavioural features which are involved in mammal locomotion compared to other tetrapods and test if they fit with the proposed phylogeny. Several factors may be checked: scaling effect in relation to gravitational constraints; geometrical distribution of masses in the body, and relative mechanical role of the limbs in the production of the external forces necessary to forward motion. Classically, it was thought that the fastest gaits used by terrestrial mammals were based upon a unique kind of limb motion co-ordination, called asymmetrical gaits, which in turn may be thought to be related to a peculiar neuronal wiring. Kinematic analysis brings an insight to this topic. Is the search for an ancestral mammalian locomotor pattern judicious? Notice the small size of many of the first mammals and their probable locomotor plasticity. (relation between grain size of the elements within the substrate and the organism scale). At a small size, the gravitational constraint is less important, and the distinction between terrestrial and arboreal has probably no sense when the limbs are the principal motor elements. There remains the importance of the geometrical distribution of body elements, the proportions of the limbs and of the head–neck complex, the tail merely as an appendix, a set of factors which may have generated the frame of constraints within which diverse locomotor modes have evolved.

Locomotion and posture allow animals to cope with some major survival problems, such as search and access for food sources, and escape from predators (Terborgh 1983, Garber 1991b, Cant 1992). Locomotion and posture seem to be the result of an interaction between the morphological features of an animal and the structure of the environment surrounding it. Most extant primates, and more specifically the New World monkeys or platyrrhines, are mainly or exclusively arboreal. Arboreal habitats are distinguished from terrestrial ones for the complex structure of tree crowns with the multiplanar setting of forests, the horizontal and vertical discontinuity, and the unsteady and randomly disposed supports. These features impose constraints on simple body displacement and arboreal animals are compelled to adopt various and more specialised locomotor and postural modes. In effect, New World monkeys show a wide range of locomotor and postural modes which are related to their body size, morphology, and dietary preferences (Rosenberger 1992). Small Callitrichids, with body weights ranging from 100 to 800 g, have claws on their hands and feet, and long hind limbs. They feed mainly on insects and tree exudates, and usually move in the discontinuous understorey, where vertical trunks dominate. They run quadrupedally on branches, are rapid and squirrel-like on vertical trunks where they use their claws, and can leap between trunks and terminal twigs (Garber 1992). Medium-sized monkeys, weighing between 1 and 5kg, tend to have higher intermembral indices. They feed less on insects and more on vegetal matter, mainly fruit, and are found in almost all forest layers. They use more quadrupedal walk, while clamber and leap between terminal branches may be equally shared. The largest monkeys, the Atelines with body weights from 5 to 12 kg, have even longer forelimbs, and prehensile tails with a ventral tactile surface. They are found in the upper forest layers and feed mainly on leaves and fruit. They clamber and suspend using their tails while moving and feeding (Rosenberger & Strier 1989).

Inselbergs and rocky outcrops constitute functional islands within the tropical forest of French Guiana. They host a characteristic vegetation mosaic (« savane-roche ») having its own dynamics, which is affected by pedological and hydrological constraints resulting from drastic thermal and hydric variations. Previous studies of this type of vegetation revealed floristic and phytocoenotic differences among stations. However, the limited range of the surveys does not afford a comprehensive view. Further studies (surveys and ecological studies) need to be carried out on every site in the department for conservation management. Until now, little research has been devoted to the fauna of these ecosystems, and especially invertebrates, although this should be corrected by a multidisciplinary study now in progress. The formations' characteristics make them ecologically fragile. Ecotourism gives rise to constraints that can be more fully understood through scientific study., Au sein de la forêt tropicale de Guyane, les inselbergs et les affleurements rocheux apparaissent comme de véritables îles qui portent une végétation en mosaïque, la « savane- roche », dotée de sa propre dynamique. Cette dernière est influencée par des contraintes pédologiques et hydrologiques particulières résultant de l'existence d'une variation marquée des paramètres thermique et hydrométrique. Les études effectuées jusqu'alors sur ce type de végétation ont révélé des différences floristiques et phytocœnotiques entre stations. Cependant, le nombre de sites visités est insuffisant pour parvenir à un niveau de compréhension générale de ces formations. La faune des savanes-roches a par contre été très peu étudiée, surtout celle des invertébrés. Un programme pluridisciplinaire en cours s'efforce de combler cette lacune. En raison de leurs caractéristiques, ces formations sont à la fois attractives et fragiles. Leur étude scientifique permet de préciser les contraintes associées à leur exploitation éco-touristique., Gasc Jean-Pierre, Sarthou Corinne, Garrouste Romain, Villiers Jean-François, Cremers Georges, Thiollay Jean-Marc. Inselbergs et savanes-roches en Guyane : biodiversité et conservation des milieux associés aux affleurements granitiques. In: Journal d'agriculture traditionnelle et de botanique appliquée, 40ᵉ année, bulletin n°1-2,1998. Conserver, gérer la biodiversité : quelle stratégie pour la Guyane ? sous la direction de Marie Fleury et Odile Poncy. pp. 311-327.

The hypothesis of a locomotor role for the free rays of Trigloporus lastoviza is supported by: (1) their periodic retraction and protraction during slow displacement over the substratum whenever the propulsive body wave responsible for swimming is not visible; (2) the integration of the rays' individual cycles into a hexapod gait apparently generated by a metachronal impulse; and (3) the kinematic features of the longest free ray in relation to the bottom-walking velocity.