Chewing function and feeding adaptations in triconodont mammals

茎-哺乳动物(哺乳类)的拟态磨牙形模式是三齿状，三个主要尖端前后对齐。这是一种具有食虫性营养的基本哺乳动物形态，如摩根齿目。从这些基本的三牙齿中，一方面出现了具有倒三角形磨牙尖端模式的进化谱系，导致了现代哺乳动物具有摩擦的牙齿。这种交替的三角形的尖端排列是现代哺乳动物高度分化的牙列的易感性。另一方面，真牙形刺谱系在没有三角剖分的情况下保持了三牙形刺的格局，并对其进行了进一步的细化。真牙轮齿是第一种通过精确咬合上下牙而发展出食肉适应能力的哺乳动物。直到晚白垩世，它们都是成功的，最大的中生代哺乳动物属于这一类(Repenomamus，体重可达15公斤)。利用我们的DFG研究单位771开发的创新的咬合指纹分析软件工具，可以首次对三牙齿的咀嚼周期进行三维建模。通过对咀嚼过程中牙齿接触面积的量化，可以估计不同牙齿和类型的效率。该项目的目的是通过高分辨率的三维模型和咬合面的条纹和微结构分析，分析从基生三齿齿的食虫性牙列到真牙形目的肉食性适应的功能转变。使用咬合指纹分析仪软件，将首次模拟咀嚼周期。关于食虫和食肉适应的假说将通过与现存哺乳动物的牙列进行比较来检验。该项目的目的除了深入了解哺乳动物的咀嚼进化外，还深入了解三牙齿在中生代脊椎动物群落中的作用。

The plesiomorphic molariform pattern of stem-mammals (mammaliaforms) is the triconodont condition, with an anterior-posterior alignment of the three main cusps. This molariform pattern characterizes basal mammaliaforms such as the morganucodontids with a purported insectivorous nutrition. From these basal triconodonts on one hand the evolutionary lineage with a reversed triangle pattern of molar cusps emerged, leading to modern mammals with tribosphenic teeth. This cusp arrangement of alternating triangles was predisposition for the highly differentiated dentitions of modern mammals. On the other hand, the eutriconodont lineage maintained the triconodont pattern without triangulation and further refined it. Eutriconodonts were the first mammals to develop a carnivorous adaptation by a precise occlusion of upper and lower teeth. They were successful up to the Late Cretaceous and the largest Mesozoic mammals belonged to this group (Repenomamus with up to 15 kg body mass). With the innovative Occlusal Fingerprint Analyser software tool that has been developed by our DFG research unit 771 the chewing cycle of triconodonts can be modeled three dimensionally for the first time. By a quantification of tooth contact areas during mastication the efficiency of the various tooth and types can be estimated. The aim of the project is to analyse the functional transformation from the insectivorous dentition of basal triconodonts to the carnivorous adaptation of Eutriconodonta by high resolution 3D models and a striation- and microtexture-analysis of the occlusal surfaces. Using the Occlusal Fingerprint Analyser software the mastication cycle will be modelled for the first time. Hypotheses on insectivrous and carnivorous feeding adaptations will be tested by comparison with dentitions of extant mammals. The aim of the project is besides an in-depth understanding of evolution of mastication in mammals an insight in the role of triconodonts in Mesozoic vertebrate communities.