比较板龙与圆顶龙的头部生物力学
COMPARATIVE CRANIAL MYOLOGY AND BIOMECHANICS OF PLATEOSAURUS AND CAMARASAURUS AND EVOLUTION OF THE SAUROPOD FEEDING APPARATUS
Abstract: Sauropodomorpha represents an important group of Mesozoic megaherbivores, and includes the largest terrestrial animals ever known. It was the first dinosaur group to become abundant and widespread, and its members formed a significant component of terrestrial ecosystems from the Late Triassic until the end of the Cretaceous. Both of these factors have been explained by their adoption of herbivory, but understanding the evolution of sauropodo- morph feeding has been hampered by the scarcity of bio- mechanical studies. To address this, the jaw adductor musculature of the basal sauropodomorph Plateosaurus and the sauropod Camarasaurus have been reconstructed. These reconstructions provide boundary conditions for finite ele- ment models to assess differences in structural performance between the two taxa. Results demonstrate that Cama- rasaurus was capable of much greater bite forces than Pla- teosaurus, due to greater relative adductor muscle mass and shape changes to the mandible. The skull and mandible of Camarasaurus are also ‘stronger’ under static biting. The Pla- teosaurus mandible appears to compromise structural effi- ciency and force transmission in order to maintain relatively high jaw closure speed. This supports suggestions of faculta- tive omnivory in basal sauropodomorph taxa. The expanded mandibular symphysis and ‘lateral plates’ of sauropods each lead to greater overall craniomandibular robustness, and may have been especially important in accommodating forces related to asymmetric loading. The functional roles of these characters, and observed general shape changes in increasing skull robustness, are consistent with hypotheses linking bulk- herbivory with the origin of Sauropoda and the evolution of gigantism.
Abstract: Sauropodomorpha represents an important group of Mesozoic megaherbivores, and includes the largest terrestrial animals ever known. It was the first dinosaur group to become abundant and widespread, and its members formed a significant component of terrestrial ecosystems from the Late Triassic until the end of the Cretaceous. Both of these factors have been explained by their adoption of herbivory, but understanding the evolution of sauropodo- morph feeding has been hampered by the scarcity of bio- mechanical studies. To address this, the jaw adductor musculature of the basal sauropodomorph Plateosaurus and the sauropod Camarasaurus have been reconstructed. These reconstructions provide boundary conditions for finite ele- ment models to assess differences in structural performance between the two taxa. Results demonstrate that Cama- rasaurus was capable of much greater bite forces than Pla- teosaurus, due to greater relative adductor muscle mass and shape changes to the mandible. The skull and mandible of Camarasaurus are also ‘stronger’ under static biting. The Pla- teosaurus mandible appears to compromise structural effi- ciency and force transmission in order to maintain relatively high jaw closure speed. This supports suggestions of faculta- tive omnivory in basal sauropodomorph taxa. The expanded mandibular symphysis and ‘lateral plates’ of sauropods each lead to greater overall craniomandibular robustness, and may have been especially important in accommodating forces related to asymmetric loading. The functional roles of these characters, and observed general shape changes in increasing skull robustness, are consistent with hypotheses linking bulk- herbivory with the origin of Sauropoda and the evolution of gigantism.
蜥脚类恐龙是中生代大型植食动物中的重要群体，也是陆地上曾经出现过的最大动物。它们也是第一种让恐龙多样性得到丰富的动物，构成了陆地生态系统中的重要组成部分。本文对原始的蜥脚形类恐龙板龙和进步的蜥脚类恐龙圆顶龙的头颅进行的生物力学研究的分析。结果表明，圆顶龙比板龙拥有更大的咬合力，这归功于更强大的肌肉组和更深的下颌。而板龙的和颌骨则能更加迅速的张合，可能与早期蜥脚形类的杂食性有关。
蜥脚类头骨演化的过程，也是其巨型化过程的一个因素。
蜥脚类头骨演化的过程，也是其巨型化过程的一个因素。