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International audience; Felids show remarkable phenotypic similarities and are conservative in behavioral and ecological traits. In contrast, they display a large range in body mass from around 1kg to more than 300kg. Body size and locomotory specializations correlate to skull, limb and vertebral skeleton morphology. With an increase in body mass, felids prey selection switches from small to large, from using a rapid skull or spine lethal bite for small prey, to sustained suffocating bite for large prey. Dietary specialization correlates to skull and front limbs morphology but no correlation was found on the spine or on the hind limb. The morphology of the sacroiliac junction in relation to ecological factors remained to be described. We are presenting a study of the overall shape of the iliac auricular surface with qualitative and quantitative analyses of its morphology. Our results demonstrate that body mass, prey selection, and bite type, crucially influence the auricular surface, where no significant effect of locomotor specialization was found. The outline of the surface is significantly more elevated dorso-caudally and the joint surface shows an irregular W-shape topography in big cats whereas the surface in small cats is smoother with a C-shape topography and less of an elevated ridge. Biomechanically, we suggest that a complex auricular surface increases joint stiffness and provides more support in heavier cats, an advantage for subduing big prey successfully during a sustained bite.

Tongue-flicking is an important sensory behavior unique to squamate reptiles in which chemical stimuli gathered by the tongue are delivered the vomeronasal organ situated in the roof of the mouth. Because tongue-flick numbers can easily be quantified, this behavior has been widely used as a measure of vomeronasal sampling in snakes using related variables such as tongue-flick rate or tongue-flick/attack score. Surprisingly, the behavior itself and especially the function of the oscillatory tongue-flicks remains poorly understood. To describe the overall kinematics of tongue-flicking in the colubrid snake Nerodia fasciata and to test predictions on the function of oscillatory tongue-flicks, we filmed the tongue-flicks of 8 adult Nerodia fasciata using 4 synchronized high-speed cameras. Three-dimensional kinematic and performance variables were extracted from the videos in order to quantify tongue movements. Based on the kinematic analysis, we demonstrate the existence of 2 functional and behavioral tongue-flick categories. Tongue-flicks with oscillations meet all the criteria for being adapted to the collection of odorants; simple downward extensions appear better suited for the rapid pick up of nonvolatile chemical stimuli from the substrate or a food item. External stimuli such as tactile and/or vomeronasal stimulation can induce a shift between these categories.

Primates are typically subdivided into two fundamentally different groups: Strepsirrhini and Haplorrhini. These two suborders are differentiated by several anatomical characteristics, among which are features of the wrist and hand. Whereas strepsirrhines are characterized by an ectaxonic hand with a longer fourth digit, haplorhines display a mesaxonic hand with a longer third digit. Two complementary studies suggest that (1) an ulnarly deviated hand with respect to the forearm during locomotion is typical for ectaxonic hands and thin branches whereas mesaxonic hands display a less-deviated posture in relation to a more terrestrial type of locomotion; (2) ulnar deviations are not always produced by ectaxonic hands and may rather be associated with locomotion in an arboreal environment. The aim of this study was to explore how arboreal substrates influence the posture of the hand and the wrist in contact with the substrate. In this context, we assessed the grasping ability of the strepsirrhine Microcebus murinus, a highly arboreal species. Here we tested the effect of branch diameter (1 and 3 cm) and orientation (horizontal and vertical) on grasp choice during arboreal locomotion. Our results show that two hand postures were observed on horizontal substrates versus three-hand postures on vertical substrates. When ulnar deviation was observed, it was typically observed on vertical substrates, particularly on thick ones. In conclusion, our data show that vertical substrates increase the variability in grasping hand postures for M. murinus and include the use of uncommon grasps compared with horizontal substrates. We suggest that more than the arboreal substrate, the frequent use of vertical supports may influence the hand biomechanics towards ulnar deviation as observed for lorisids and indriids.

607..622 Although prey capture is thought to be based on the coordinated movements of the jaw and locomotor apparatus (i.e. the vertebral column and the limbs), jaw–neck–forelimb coordination has never been compared among related species. The kinematics of jaw, neck, and forelimb movements were recorded in lizards that use jaw prehension: Gerrhosaurus major, Tupinambis merianae, Varanus niloticus, and Varanus ornatus. These species provide a comparative framework to discuss the influence of morphological differences and ecological convergence on the jaw–neck–forelimb coordination patterns. Jaw–neck–forelimb coordination was quantified by determining whether maximum neck elevation and maximum forelimb flexion are synchronized with either the start of jaw opening or maximum gape. Significant differences in the jaw–neck–forelimb coordination pattern among species were observed, with maximum neck elevation being synchronized with the start of jaw opening in varanids, whereas in T. merianae and G. major, it is achieved closer to maximum gape. Differences in locomotor–feeding integration are suggested to be related to dietary specializations, and as such may play a role in feeding adaptation. The jaw–neck–forelimb coordination pattern used by varanids may indeed be advantageous to prepare a quick strike triggered from further away, providing a critical advantage when feeding on evasive prey. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 607–622.

In arboreal animals such as the grey mouse lemur (Microcebus murinus Miller, 1777), leaping is the most frequent strategy for predator avoidance. The aim of this study was to characterise the locomotor adaptation in response to the structural constraint of the habitat (i.e., position of the landing substrate). Thus, we characterised the push-off phase by inducing the lemurs to leap up to a range of heights from horizontal to their own individual highest performance. Using uniplanar high-frequency cineradiographs collected in a sagittal plane, the relative contributions of the centre of mass (CoM) velocity vector magnitude and orientation to leaping performance were evaluated. The kinematics of the push-off phase showed that for low landing heights, leaping performance was essentially due to hip and knee extensions. Higher leaps seemed to be related to an increase in ankle contribution. At all leaping heights, the proximal-to-distal sequence of the hind limb joints controlled the orientation and magnitude of the M. murinus CoM velocity vector while pushing off. Finally, the analysis of the velocity vector at the onset of take-off suggested that the optimal solution for predator avoidance was to leap for horizontal distance and not for vertical distance.

Detailed descriptions of tongue morphology of members of Squamata that refer to functional implications other than food processing are rare. Herein we focus on the morphology of the dorsal epithelium and internal structure of the tongue of the Leopard Gecko, Eublepharis macularius, emphasizing the foretongue and its relation to fluid uptake. We employ both scanning electron microscopy and serial histology to examine the morphology of the entire tongue, its component regions, and its situation in the oral chamber. We recognize five distinct morphological regions of the dorsal tongue surface, each of which is distinctive both morphologically and histologically. The foretongue bears papillae quite different in structure and spacing from those of all other tongue regions, and these non-glandular structures are involved in gathering and transporting fluid from the environment. Fluid unloaded from the foretongue in the region of the vomeronasal sinus is channeled through the network of cuboidal papillae and directed towards a pair of compartments lateral to the tongue in which fluid pools during a drinking bout. This allows the dorsal surface of the mid- and hind-tongue, which are involved in food processing and manipulation, to be largely segregated from the pathway of fluid flow. We relate our findings to descriptions of the tongue of other taxa, and propose functional hypotheses for the observed morphology. This study provides new anatomical information upon which future studies of the functional morphology of the buccal apparatus in the Gekkota can be based.

SUMMARYIn tetrapods, feeding behaviour in general, and prey capture in particular,involves two anatomical systems: the feeding system and the locomotor system. Although the kinematics associated with the movements of each system have been investigated in detail independently, the actual integration between the two systems has received less attention. Recently, the independence of the movements of the jaw and locomotor systems was reported during tongue-based prey capture in an iguanian lizard (Anolis carolinensis), suggesting a decoupling between the two systems. Jaw prehension, on the other hand, can be expected to be dependent on the movements of the locomotor system to a greater degree. To test for the presence of functional coupling and integration between the jaw and locomotor systems, we used the cordyliform lizard Gerrhosaurus major as a model species because it uses both tongue and jaw prehension. Based on a 3-D kinematic analysis of the movements of the jaws, the head, the neck and the forelimbs during the approach and capture of prey, we demonstrate significant correlations between the movements of the trophic and the locomotor systems. However, this integration differs between prehension modes in the degree and the nature of the coupling. In contrast to our expectations and previous data for A. carolinensis,our data indicate a coupling between feeding and locomotor systems during tongue prehension. We suggest that the functional integration between the two systems while using the tongue may be a consequence of the relatively slow nature of tongue prehension in this species.

International audience; Agamid lizards use tongue prehension for capturing all types of prey. The purpose of this study was to investigate the functional relationship between tongue structure, both surface and musculature, and function during prey capture in Pogona vitticeps. The lack of a detailed description of the distribution of fibre-types in the tongue muscles in some iguanian lizards has hindered the understanding of the functional morphology of the lizard tongue. Three methodological approaches were used to fill this gap. First, morphological analyses were performed (i) on the tongue surface through scanning electron microscopy, and (ii) on the lingual muscle by histological coloration and histochemistry to identify fibre-typing. Secondly, kinematics of prey capture was quantified by using high-speed video recordings to determine the movement capabilities of the tongue. Finally, electromyography (EMG) was used to identify the motor pattern tongue muscles during prey capture. Morphological and functional data were combined to discuss the functional morphology of the tongue in agamid lizards, in relation to their diet. During tongue protraction, M. genioglossus contracts 420 ± 96 ms before tongue-prey contact. Subsequently, Mm. verticalis and hyoglossus contract throughout tongue protraction and retraction. Significant differences are found between the timing of activity of the protractor muscles between omnivorous agamids (Pogona sp., this study) and insectivorous species (Agama sp.), despite similar tongue and jaw kinematics. The data confirm that specialisation toward a diet which includes more vegetal materials is associated with significant changes in tongue morphology and function. Histoenzymology demonstrates that protractor and retractor muscles differ in fibre composition. The proportion of fast glycolytic fibres is significantly higher in the M. hyoglossus (retractor muscle) than in the M. genioglossus (protractor muscle), and this difference is proposed to be associated with differences in the velocity of tongue protrusion and retraction (5 ± 5 and 40 ± 13 cm s(-1) , respectively), similar to Chamaeleonidae. This study provides a way to compare fibre-types and composition in all iguanian and scleroglossan lizards that use tongue prehension to catch prey.

The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake’s head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake’s jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

From lizards to snakes, the trophic system of squamates exhibits at least six major modifications correlated with different feeding strategies. Beginning in lizards, these include 1) shift from tongue to jaws as the primary means of prey capture, accompanied by specialization of the tongue for chemoreception, and 2) increasing skull kineticism. These features continue into snakes along with 3) unilateral jaw displacement during swallowing accompanied by 4) increasing skull kineticism, 5) development of the cervical vertebrae into a lever system for launching the strike, 6) addition of sensory modalities (thermoreception) in some snakes, and in advanced snakes, 7) shift from mechanical to chemical means of predation. Many fundamental features elaborated into the highly kinematic and jaw-based feeding system of snakes actually appear first within lizards. However, the highly kinetic skull of snakes represents not so much an extrapolation of lizard kinesis, as it does a rebuilding, even redesign, of the skull to achieve its high level of kinesis.

Import JabRef | WosArea Zoology; International audience; Among primates, apes and monkeys are known to use their hands and to exhibit independent control of their fingers. In comparison, Prosimii are thought to have less digital individualization and to use their mouth more commonly for prehension. Unfortunately, prehension and manipulation studies in Prosimii have been conducted in conditions constraining the subject to grasp with the hand. Moreover, the effect of food size remains unexplored, even though it could affect the use of the hands versus the mouth. Thus, whether prosimians use the hand or the mouth to grasp and manipulate food items of different sizes in unconstrained conditions remains unclear. To address this question, we characterized the eating and manipulation patterns of Microcebus murinus in unconstrained conditions, using three food sizes. The results showed that M. murinus showed (i) an eating pattern similar to that of rodents, with smaller food items being grasped with the mouth, (ii) a greater tendency to use the hands for prehension of larger foods, and (iii) plasticity during food manipulation similar to that which has been observed in rodents. These results are discussed in the framework of grasping in mammals and are used to discuss the origins of prehension in primates. Copyright (C) 2011 S. Karger AG, Basel

SUMMARYThe purpose of this study was to investigate the pattern of coordinations of the hindlimb joints in the world's smallest living primate (Microcebus murinus). The sequencing and timing of joint rotations have been analyzed in five adult males performing maximal leaping from a take-off immobile platform to their own wooden nest. Angular kinematics of hip, knee, angle and metatarso-phalangeal (MT) joints were deduced from high-speed X-ray films in the sagittal plane of the animals. The body mass center (BMC) of the lemurs was assimilated to their iliac crest. The maximal airborne performance of the lemurs was 0.33±0.04 m, which represented 2.55±0.36 times their snout–vent length. Take-off instant occurred 72±7 ms after the start of the push-off, with a BMC velocity of 3.23±0.48 m s−1, oriented 55±14 deg. with the horizontal plane. The kinematic analysis of the joints and musculo-tendon architecture of the M. murinus plantar flexors pointed out mechanical power amplifier mechanisms (i.e. stretch-shortening cycle of hindlimb muscles and proximo-to-distal sequence).

High-speed cinematography (100 frames/s) was used to allow quantitative analysis of the kinematic profiles of tongue and jaw displacements during chemosensory activities in the scleroglossan lizard Lacerta viridis. The types of tongue flicking were simple downward extensions (SDE), single oscillations (SOC), and submultiple oscillations (SMOC) of the tongue out of the mouth. The SMOC type involves a downward or upward movement of the tongue performed before a typical oscillation and it is therefore suggested that this is an intermediate category of flick between the typical SOC and MOC of lizards. Closing and opening of the mouth in SDE, SOC, and SMOC cycles may or may not be separated by a stationary stage during which the jaws are held open at a constant gape. The duration of this stationary interval increases from SDE to SMOC. Gape cycles do not show any division into slow and fast stages. The gape is produced largely by depression of the lower jaw; the upper jaw is slightly elevated by protrusion of the tongue. Patterns of correlation of kinematic variables depicting jaw and tongue movements differed between SDE, SOC, and SMOC. A principal component analysis shows that the three flick types overlap in a multivariate space constructed from the kinematic variables depicting jaw and tongue displacements. Overlap between SOC and SMOC categories is greater than that between SOC, SMOC, and SDE categories. The kinematic patterns of tongue displacement during SMOC in Lacerta viridis show similarities with those of MOC in other lizards and in snakes. Kinematically, the pattern of jaw and tongue displacements of Lacerta viridis during chemosensory activities shows similarities with those that occur during drinking and prey capture.

SUMMARY In most terrestrial tetrapods, the transport of prey through the oral cavity is accomplished by movements of the hyolingual apparatus. Morphological specializations of the tongue in some lizard taxa are thought to be associated with the evolution of vomerolfaction as the main prey detection mode. Moreover, specializations of the tongue are hypothesized to compromise the efficiency of the tongue during transport; thus, driving the evolution of inertial transport. Here we use a large teiid lizard, Tupinambis merianae, as a model system to test the mechanical link between prey size and the use of inertial feeding. We hypothesize that an increase in prey size will lead to the increased recruitment of the cranio-cervical system for prey transport and a reduced involvement of the tongue and the hyolingual apparatus. Discriminant analyses of the kinematics of the cranio-cervical, jaw and hyolingual systems show that the transport of large prey is indeed associated with a greater utilization of the cranio-cervical system (i.e. neck and head positioning). The tongue retains a kinematic pattern characteristic of lingual transport in other lizards but only when processing small prey. Our data provide evidence for an integration of the hyolingual and cranio-cervical systems; thus, providing partial support for an evolutionary scenario whereby the specialization of the tongue for chemoreception has resulted in the evolution of inertial transport strategies.

The leatherback turtle, Dermochelys coriacea, which is particularly well adapted to marine life, uses a mode of terrestrial locomotion that does not involve raising the entire body; it drags itself instead, which is unique to heavy animals. The primary pattern of tetrapods, using alternate movements and a diagonal sequence of the limbs, is replaced by a specific repertory of periodic and synchronous movements of the fore- and hind-limbs. The forelimbs, which have evolved into large paddles, produce lifting and forward movements of the body as if the turtle were "walking on crutches." During terrestrial locomotion, the forelimb movement, derived from swimming, is rather similar to that used during vigorous swimming, except for a reduction of the upstroke.

SUMMARYOnly a few studies on quadrupedal locomotion have investigated symmetrical and asymmetrical gaits in the same framework because the mechanisms underlying these two types of gait seem to be different and it took a long time to identify a common set of parameters for their simultaneous study. Moreover,despite the clear importance of the spatial dimension in animal locomotion,the relationship between temporal and spatial limb coordination has never been quantified before. We used anteroposterior sequence (APS) analysis to analyse 486 sequences from five malinois (Belgian shepherd) dogs moving at a large range of speeds (from 0.4 to 10.0 m s–1) to compare symmetrical and asymmetrical gaits through kinematic and limb coordination parameters. Considerable continuity was observed in cycle characteristics,from walk to rotary gallop, but at very high speeds an increase in swing duration reflected the use of sagittal flexibility of the vertebral axis to increase speed. This change occurred after the contribution of the increase in stride length had become the main element driving the increase in speed– i.e. when the dogs had adopted asymmetrical gaits. As the left and right limbs of a pair are linked to the same rigid structure, spatial coordination within pairs of limbs reflected the temporal coordination within pairs of limbs whatever the speed. By contrast, the relationship between the temporal and spatial coordination between pairs of limb was found to depend on speed and trunk length. For trot and rotary gallop, this relationship was thought also to depend on the additional action of trunk flexion and leg angle at footfall.

We quantified gait and stride characteristics (velocity, frequency, stride length, stance and swing duration, and duty factor) in the bursts of locomotion of two small, intermittently moving, closely related South American gymnophthalmid lizards: Vanzosaura rubricauda and Procellosaurinus tetradactylus. They occur in different environments: V. rubricauda is widely distributed in open areas with various habitats and substrates, while P. tetradactylus is endemic to dunes in the semi-arid Brazilian Caatinga. Both use trot or walking trot characterised by a lateral sequence. For various substrates in a gradient of roughness (perspex, cardboard, sand, gravel), both species have low relative velocities in comparison with those reported for larger continuously moving lizards. To generate velocity, these animals increase stride frequency but decrease relative stride length. For these parameters, P. tetradactylus showed lower values than V. rubricauda. In their relative range of velocities, no significant differences in stride length and frequency were recorded for gravel. However, the slopes of a correlation between velocity and its components were lower in P. tetradactylus on cardboard, whereas on sand this was only observed for velocity and stride length. The data showed that the difference in rhythmic parameters between both species increased with the smoothness of the substrates. Moreover, P. tetradactylus shows a highly specialised locomotor strategy involving lower stride length and frequency for generating lower velocities than in V. rubricauda. This suggests the evolution of a central motor pattern generator to control slower limb movements and to produce fewer and longer pauses in intermittent locomotion.

Background. The ability to detect chemical cues is highly developed in Scleroglossa, and particularly in anguid lizards. This ability was predicted because anguids possess a well-developed vomeronasal organ (VNO) (or Jacobson's organ) and rely largely on chemical cues in various behaviours as other active foragers. In this work, we have investigated the possible functional association between tongue flicking and the VNO in the lizard Anguis fragilis. Methods. The morphology of the tongue and the buccal cavity was investigated by light and scanning electron microscopy. The kinematics of tongue and jaw movements was studied by high speed cinematography. Results. The epithelial cells of the ventral aspect of the tongue tips show microstructures (microridges, microfacets, micropores) which are not present on other areas of the mouth. Beneath the tongue, the floor of the buccal cavity shows two concave-like elevations suggesting a structural analogy with the anterior processes described in snakes. The apex and the internal margin of these processes bear parallel oblique ridges. Taste buds occur anteriorly on the buccal floor and on the palate and are abundant on the internal side and on the edge on the anterior processes. The tongue showed three modes of tongue flicking: simple downward extension, single oscillation, and multiple oscillations. At each tongue flick, the ventral surface of the tips was observed contacting the substratum. Immediately after the tongue retraction, the buccal floor moved slightly upward. The observation of tongue flicking with the mouth open showed that the anterior processes moved upward when the tongue was retracted. Conclusions. These observations suggest the following: (1) during tongue flicking the ventral surface of the tongue tips invariably makes contact with the substratum; (2) the microstructures of the tongue tips and the ridges of the anterior processes might be helpful for collecting and receiving, respectively, chemicals during tongue flicking; (3) the anterior processes may be apposed on the roof of the mouth next to the ducts of VNOs when the buccal floor is fully elevated; (4) due to their localization, the taste buds could be equally stimulated by the molecules transferred during tongue flicking. © 1994 Wiley-Liss, Inc.

The hyolingual system of Squamata is a highly versatile system used in different feeding, drinking, chemoreception, and social behaviors. In each of these activities, either the entire hyolingual system or one of its elements is used. For instance, in the majority of lizards, the tongue acts as the main element for liquid uptake, intraoral food and liquid transport, and in chemoreception, whereas the hyoid apparatus plays a major role during social interactions by acting on the ventral floor of the throat. In varanids, the hyoid apparatus is involved in both deglutition of foods and liquids, and during social displays.

Squamate prey capture evolved in two general directions; one toward an emphasis upon lingual prehension and the other toward an emphasis upon jaw prehension. In basal squamates (Iguania) lingual prehension characterizes prey capture. All other squamates (Scleroglossa) tend to use their jaws for prey prehension and the role of the tongue as a prehensile organ is reduced. However, within some scleroglossan lizards, lingual and jaw modes of prehension are present Selection of a distinct prehension mode during a feeding bout in these lizards has been hypothesized to be related to prey size. To test for the presence of lingual prehension and correlation with prey size, we examined feeding behavior in the blue-tongued skink, Tiliqua scincoides using two prey types (mealworm and cricket). We confirmed that this skink uses both lingual and jaw modes of prehension with accompanying characteristic jaw kinematic profiles. With crickets, only jaw prehension was exhibited, but both modes were used when feeding on equivalently sized prey, mealworms. Consequently, prehension mode is not exclusively elicited by prey size. We, therefore, hypoth- esize that selection of prehension modes, lingual or jaws, in these basal scleroglossans also includes prox- imate factors related to prey behavior.