Isotopic and anatomical evidence of an herbivorous diet in the Early Tertiary giant bird Gastornis. implications for the structure of Paleocene terrestrial ecosystems.

The mode of life of the early Tertiary giant bird Gastornis has long been a matter of controversy. Although it has often been reconstructed as an apex predator feeding on small mammals, according to other interpretations, it was in fact a large herbivore. To determine the diet of this bird, we analyze here the carbon isotope composition of the bone apatite from Gastornis and contemporaneous herbivorous mammals. Based on (13)C-enrichment measured between carbonate and diet of carnivorous and herbivorous modern birds, the carbonate δ(13)C values of Gastornis bone remains, recovered from four Paleocene and Eocene French localities, indicate that this bird fed on plants. This is confirmed by a morphofunctional study showing that the reconstructed jaw musculature of Gastornis was similar to that of living herbivorous birds and unlike that of carnivorous forms. The herbivorous Gastornis was the largest terrestrial tetrapod in the Paleocene biota of Europe, unlike the situation in North America and Asia, where Gastornis is first recorded in the early Eocene, and the largest Paleocene animals were herbivorous mammals. The structure of the Paleocene terrestrial ecosystems of Europe may have been similar to that of some large islands, notably Madagascar, prior to the arrival of humans.

Limb-bone histology of temnospondyls: implications for understanding the diversification of palaeoecologies and patterns of locomotion of Permo-Triassic tetrapods.

The locomotion of early tetrapods has long been a subject of great interest in the evolutionary history of vertebrates. However, we still do not have a precise understanding of the evolutionary radiation of their locomotory strategies. We present here the first palaeohistological study based on theoretical biomechanical considerations among a highly diversified group of early tetrapods, the temnospondyls. Based on the quantification of microanatomical and histological parameters in the humerus and femur of nine genera, this multivariate analysis provides new insights concerning the adaptations of temnospondyls to their palaeoenvironments during the Early Permian, and clearly after the Permo-Triassic crisis. This study therefore presents a methodology that, if based on a bigger sample, could contribute towards a characterization of the behaviour of species during great evolutionary events.

Limb preference in the gallop of dogs and the half-bound of pikas on flat ground.

During fast locomotion--gallop, half-bound, bound--of quadruped mammals, the ground contact of the limbs in each pair does not alternate symmetrically. Animals using such asymmetrical gait thus choose whether the left or the right limb will contact the ground first, and this gives rise to limb preference. Here, we report that dogs (Mammalia, Carnivora) and pikas (Mammalia, Lagomorpha) prefer one forelimb as trailing limb and use it as such almost twice as often as the other. We also show that this choice depends on the individual and is not a characteristic of the species, and that the strength of the preference was not dependent on the animal's running speed.

Kinematic parameters of terrestrial locomotion in cursorial (ratites), swimming (ducks), and striding birds (quail and guinea fowl).

The importance of size, functional features and morphological features in adaptation for walking in birds were studied. The time and space kinematic parameters of locomotion were compared in two running birds, the ratites (rhea, kiwi, Paleognatiforms), in two swimming birds, (ducks) and two striding birds, (quail and Guinea fowl). The results showed that in the two phases, stance and swing, the time and space parameters worked in opposite ways: the duration of the swing was constant, but its length increased with speed. In contrast, the duration of the stance was correlated to speed, while its length was not (except in ducks). In all the birds, a higher speed was achieved by a decrease of the stance duration, and an increase of the swing length. The kinematic parameters were not used in the same way in all species: There is a size effect and large birds increase their speed mainly by increasing the frequency of their movements and the small species increase mainly their amplitude. Nevertheless, it is not the main factor and morphology, such as swimming adaptation features of the ducks, and behaviour, are important because they modify the mechanical constraints and influence the kinematics parameters.

[Expression of growth dynamic in the structure of periosteal bone in Anas platyrhynchos]. / Expression de la dynamique de croissance dans la structure de l'os périostique chez Anas platyrhynchos.

An experimental study of the periosteal bone growth in the mallard from 42 to 154 post hatching days shows: (1) a noticeable time difference in the local biological age of the diaphyseal cortices between various long bones; (2) great differences in their histological structures, at a given individual age, expressing commensurate differences in local growth rates. Those results emphasize the importance of local factors to interpret the typology of the primary (periosteal) bone tissues. Experimental results allow to quantify the relationships between bone tissue typology and the velocity of its radial deposition.

Mechanics of standing in birds: functional explanation of lameness problems in giant turkeys.

1. The parameters used for the mechanics of standing in birds are defined and compared for two strains of turkeys, a giant, broad-breasted strain (up to 40 kg), the result of artificial selection, and a traditional, smaller bird (9 kg), in order to show whether the mechanics of standing are modified by selection. 2. Using a geometrical similarity hypothesis, it was found that, although the locomotor apparatus of both strains are similar, the stresses on the pelvic muscles of broad-breasted turkeys are increased. This is induced by the anterior position of the centres of gravity of their trunks, the result of selected pectoral hypertrophy. 3. The modification to the mechanics of standing may be related to the increase in locomotor disease in strains of giant turkeys.

[Analytical study of the locomotion of the meat turkey cock. Comparison between sound turkeys and turkeys with locomotor problems]. / Etude analytique de la locomotion du dindon de chair. Comparaison entre dindons sains et dindons atteints de troubles locomoteurs.

A comparative locomotion analysis of healthy and lame male commercial turkeys was carried out. Walking turkeys were filmed from both right and left lateral views. Video films were analysed. The coordination and the succession of hind limb movements were studied with time and space components. The gait of healthy turkeys was a walk with perfectly symmetrical and repeatable hind limb movements. All lame turkeys' movements showed abnormalities in space-time coordination. These abnormalities were bilateral but non-symmetrical, intermittent, and non-systematic. Their intensity increased with increase in the degree of clinical handicap. However, in all lame turkeys, the degree of an abnormal tibial movement was observed, ie a shorter amplitude of forward movement with variable intensity.

Comparative gait analysis of two strains of turkey, Meleagris gallopavo.

1. Economic requirements have encouraged farmers to select broad-breasted strains of turkeys (Meleagris gallopavo). These birds are very heavy (more than 30 kg), have pectoral hypertrophy and are frequently lame. Traditional turkeys, closer to wild birds, weigh 9 kg on average. 2. Gaits, which are motor pattern expressions, seem to be linked to species morphology. However, no significant differences are evident between the gaits of traditional and broad-breasted strains. 3. Yet, posterior views of the walk of both strains show lateral oscillations, which are very slight in the traditional one but very marked in the broad-breasted one. 4. In the latter, modification of the centre of gravity path may increase the energetic cost of walking and be associated with problems of lameness. 5. Therefore, if the genetic pool permits an increase in weight of broad-breasted turkeys, then extrinsic factors, such as gravity constraints, may limit this evolution.

[Myology of the pelvic limb of the domestic turkey Meleagris gallopavo]. / Myologie du membre pelvien du dindon domestique Meleagris gallopavo.

Pelvic limbs of 150 turkeys from a normal farmer's strain and from a Broad Breasted strain were examined by dissection to determine growth from birth to adulthood. Schematic figures and photographs show the course of the dissection. The pictures show how the muscles are related to the skeleton of the pelvic limb in the farmer's strain as well as demonstrate the surfaces upon which the muscles insert. The configuration of the muscles in the turkey are similar to the generally known model in birds. It is necessary, however, to describe the musculature and its relations to the skeleton before functional conclusions can be drawn or before studies of deficiencies in movements related to the selection of broad breasted strains can be made.