Body cavity size in fossil chewing herbivores, non-chewing herbivores, and carnivores: Implications for GIT volume and gigantism.

咀嚼食草动物、非咀嚼食草动物和食肉动物的体腔大小：对胃肠道体积和巨人症的影响。

• 批准号: 169824555
• 负责人: Professor Dr. Marcus Clauss
• 金额: --
• 依托单位: Institut für Veterinäre Physiologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/169824555?language=en
• 关键词: Body; cavity; size; fossil; chewing

In herbivores, digestion of plant material by symbiotic gut microbes is a function of both ingesta retention (time available for fermentation) and particle size. Because smaller particle size accelerates digestion rate, retention time and particle size reduction can compensate for each other. Thus, animals lacking a particle size reduction mechanism (non-chewing dinosaurs such as sauropods, stegosaurs, ankylosaurs) should have adopted long ingesta retention times, facilitated by comparatively large (voluminous) guts. Although body shape has been suggested as an indicator for the volume of the coelomic cavity and hence the gut, quantitative investigations are lacking. Using digital capture of mounted skeletons of extinct herbivores and live animals, body shape reconstructions and volume calculations, we will test the hypotheses that a) carnivorous dinosaurs, reptiles, and mammals have a less voluminous coelomic/abdominal cavity than their herbivore counterparts, and in particular that b) non-chewing herbivorous dinosaurs and more primitve fossil reptiles have a more voluminous coelomic cavity than chewing herbivorous dinosaurs and mammals. We predict that the volume of the body cavity is an important variate in herbivore digestive morphophysiological adaptation, with dinosaurs – where both chewing and non-chewing forms exist – being the ideal model organisms for this principle, displaying more variability in this parameter than mammals. In particular, we predict that a disproportionately large body cavity is a decisive characteristic of sauropods (that facilitated a high food intake and metabolism in spite of a lack of mastication).

在食草动物中，共生肠道微生物对植物材料的消化是摄入物保留（发酵可用时间）和颗粒大小的函数。由于较小的颗粒尺寸会加快消化速度，因此保留时间和颗粒尺寸的减小可以相互补偿。因此，缺乏颗粒尺寸减小机制的动物（非咀嚼恐龙，如蜥脚类恐龙、剑龙、甲龙）应该采用较长的摄入物保留时间，这得益于相对较大（体积较大）的肠道。尽管身体形状被认为是体腔体积以及肠道体积的指标，但仍缺乏定量研究。通过对已灭绝的食草动物和活体动物的骨骼进行数字捕捉、体型重建和体积计算，我们将测试以下假设：a) 肉食性恐龙、爬行动物和哺乳动物的体腔/腹腔体积小于食草动物，特别是 b) 非咀嚼式食草恐龙和更原始的爬行动物化石具有 体腔比咀嚼食草恐龙和哺乳动物更大。我们预测，体腔的体积是草食动物消化形态生理适应的一个重要变量，恐龙（同时存在咀嚼和非咀嚼形式）是这一原理的理想模型生物，在该参数上比哺乳动物表现出更多的变异性。特别是，我们预测，不成比例的大体腔是蜥脚类恐龙的决定性特征（尽管缺乏咀嚼，但仍促进了高食物摄入和新陈代谢）。