中华竹鼠与甘肃鼢鼠咀嚼肌结构和功能的比较

为了解中华竹鼠与甘肃鼢鼠对食物选择的适应机制，对它们的咀嚼肌及相关的骨学特征作了比较解剖，并运用生物力学原理分析下颌运动方式及食物加工过程的咀嚼效率。结果表明：中华竹鼠下颌咀嚼以上下和左右运动为主，这种运动方式与其下颌关节窝呈卵圆形、左右侧颊齿列非平行排列及臼齿加宽等适应性结构有关；甘肃鼢鼠下颌咀嚼以水平面的前后向运动为主，该运动方式与其下颌关节窝里沟槽状、左右侧颊齿列平行排列等适应性结构有关。中华竹鼠的门齿切割效率与臼齿咀嚼效率均大于甘肃鼢鼠，暗示着前者比后者对树木的根系有着更大的破坏能力。

A comparison of structure and function on masticatory apparatus between Chinese bamboo rat and common Chinese zokors

The anatomy of the masticatory apparatus, movement pattern of mandible and masticatory efficiencies of cheek teeth row during mastication are compared between Chinese bamboo rat (Rhizomys sinensis)and common chinese zokor (Myospalax cansus) in order to better understand the adaptive mechanism of the two underground rodents. The analysis is based on biomechanical principles as well as quantitative comparisons between the two species. The results indicated that mandible of common Chinese zokor can freely move back and forth during mastication,suitable to grinding plant fibres;while the movement of mandible of Chinese bamboo rat is limited to left-right direction on the level plane. Correspondingly, the skulls have developed some characters to facilitate these two movement patterns respectively. Because of the different feeding habits,cutting efficiencies of incisors and masticatory efficiencies of molars in Chinese bamboo rat are higher than in common Chinese zokor, implying that Chinese bamboo rat has much stronger ability to destroy the root of trees than common Chinese zokor does.