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In tetrapods, the ability to ingest food on land is based on certain morphological features of the oropharynx in general and the feeding apparatus in particular. Recent paleoecological studies imply that terrestrial feeding has evolved secondarily in turtles, so they had to meet the morphological oropharyngeal requirements independently to other amniotes. This study is designed to improve our limited knowledge about the oropharyngeal morphology of tortoises by analyzing in detail the oropharynx in Manouria emys emys. Special emphasis is placed on the form and function of the tongue. Even if Manouria is considered a basal member of the only terrestrial turtle clade and was hypothesized to have retained some features reflecting an aquatic ancestry, Manouria shows oropharyngeal characteristics found in more derived testudinids. Accordingly, the oropharyngeal cavity in Manouria is richly structured and the glands are large and complexly organized. The tongue is large and fleshy and bears numerous slender papillae lacking lingual muscles. The hyolingual skeleton is mainly cartilaginous, and the enlarged anterior elements support the tongue and provide insertion sides for the well-developed lingual muscles, which show striking differences to other reptiles. We conclude that the oropharyngeal design in Manouria differs clearly from semiaquatic and aquatic turtles, as well as from other reptilian sauropsids.

Sub-lm computed tomography (sub-lm-CT) was used to determine the fibre orientation and fibre length distribution in long glass fibre filled polypropylene. For data evaluation two different concepts based on the application of a sequence of different filters were applied. The first concept is based on segmentation by binarisation using a global threshold, followed by a detailed analysis of regions where fibres are touching. The second concept is based on analysis of the original gray value image. For each voxel the local fibre orientation is determined by calculating the Hessian Matrix and analysing its Eigen values.The effectivity of the two data analysis concepts in determining orientation and length was investigated. For this purpose the algorithms were applied to specimens with four different levels of fibre content: 1, 5, 10 and 30 % by weight. To quantify the level of error in fibre determination, a minimum and average probability for correct fibre determination were estimated.The results show a strong dependence of the level of error on the fibre content. Whilst the determination of fibre orientation is not significantly affected, determination of fibre length distribution is significantly influenced by fibre content. For samples with fibre content above 5 %, concept 1 does not produce correct representations of all fibres. In particular, problems arise if the fibres are touching. Concept 2 delivers much better results and represents most of the fibres correctly even at higher fibre content levels and for touching fibres. This was proven by using artificial CT-data sets generated by CT-simulation and by systematic comparisons. A practical application of the CT-evaluation pipeline is presented for glass fibre reinforced rings produced by injection-moulding and extrusion. For both samples the orientation tensors are calculated and the orientations of the fibres are visualized in three dimensions by colour coding.

The present study examined the kinematic patterns of initial food uptake, food transport, pharyngeal packing and swallowing in the common musk turtle Sternotherus odoratus. These data are supplemented by morphological descriptions of the skull and the hyolingual complex. Although the hyoid is mainly cartilaginous, S. odoratus still use exclusively hydrodynamic mechanisms in prey capture and prey transport. The tongue is relatively small, with weakly developed intrinsic musculature. We propose that the elasticity of the hypoglossum and the hyoid body impacts the capability of S. odoratus to suction feed, but allows these turtles to effectively re-position the food items within the oropharyngeal cavity during transport, manipulation and pharyngeal packing. We standardised conditions in all feeding events by using food items of the same consistence and size, and by always offering the food at the same position at the bottom of the aquarium. Nonetheless, the measured kinematic values varied considerably. The duration of prey capture and prey transport cycles were relatively long in S. odoratus compared to other freshwater turtles studied so far. The initiation of hyoid retraction relative to the onset of jaw opening can be modulated not only in prey capture but also in prey transport cycles. In the common musk turtle, the jaw and hyoid movements apparently have a low level of integration.

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