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Geometric morphometric of postnatal size and shape changes in the cranium of cape hare (Lagomorpha,Leporidea,Lepus capensis)

GE Deyan,LV Xuefei,XIA Lin,HUANG Chengming,YANG Qisen   

  1. Institute of Zoology,Chinese Academy of Sciences
  • Online:2012-02-29 Published:2012-02-20

草兔胚后发育过程中头骨大小与形状变化的几何形态学分析(兔形目:兔科)

葛德燕,吕雪霏,夏霖,黄乘明,杨奇森   

  1. 中国科学院动物研究所

Abstract: We analyzed the geometric morphometrics analysis of the crana of 58 Lepus capensis of various ages using 180 landmarks/semi-landmarks. These exhibited rapid establishment of structure and allometric growth in different morphological components. Primary size and shape changes occurred from infant to age I (within six months). Nasal size displayed the most prominent positive allometry. Frontal and orbital grew nearly isometrically with the overall size change of the cranium. The parietal,tympanic bulla and foramen magnum displayed negative allometry. Growth trajectories were illustrated for the dorsal,ventral and lateral view of the cranium. Allometric shape changes were observed in the nasal,premaxilla and supraorbital process,as well as in the longitudinal axis of the cranium. The overall shape of the cranium was narrowed. These ontogenetic size and shape changes are beneficial in establishing a complete cranial system in young hares,particularly, in improving ventilation of the respiratory system,enhancing the ability to maintain vigilance,and in stabilization over a diverse range of locomotion activities as well as strengthening the ability for solid food acquisition. This pattern of allometric growth probably is one of the main functional adaptations in herbivorous mammals that have a cursorial lifestyle.

Key words: Allometry, Cranium morphology, Geometric morphometrics, Lagomorpha, Ontogeny

摘要: 在本文中,我们使用几何形态学的研究方法对58 个处于不同年龄阶段的草兔头骨进行了分析。分析中总共使用来自头骨背面、腹面和侧面的180 个标点和半标点。研究结果表明,草兔在胚后发育早期即迅速建立起与成年个体近似的形态结构,组成头骨的不同形态单元存在显著的异速生长现象,主要的形变发生在幼年至年龄1 阶段,即出生后的6 个月以内。从大小的变化来看,鼻骨在胚后发育过程中呈现正的异速生长,额骨和眼眶区则与头骨整体大小变化基本等速,而顶骨、听泡和枕骨大孔则呈现显著的负异速生长。我们亦用几何形态学的方法绘制出头骨在生长发育早期和晚期不同部位的形态变化轨迹,这一结果显示较显著的形状变化发生在鼻骨、前颌骨、眶上突和头骨的纵轴方向。头骨整体形态在胚后发育过程中伸长并变窄。这些变化将有利于幼兔较早实现完善的头部系统的建立,尤其有利于提高呼吸系统的通风能力,提高在高强度的捕食压力下保持警觉,在多样的运动过程中保持身体平稳的能力,也可能进一步提高了对固态食物的处理能力。这种异速生长模式可能是善于奔跑的植食性哺乳动物在功能需求上的一种适应性进化特征。

关键词: 生长发育, 几何形态学, 异速生长, 头骨形态, 兔形目