Dawson S D
Laboratory of Anatomy, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6045.
J Morphol. 1994 Nov;222(2):215-21. doi: 10.1002/jmor.1052220208.
This study examines the allometric scaling relationships of the cetacean humerus, radius, and ulna. Bone lengths and diameters were measured for 20 species of odontocete and three species of mysticete cetaceans, representing eight of the nine extant cetacean families. The scaling of individual bone proportions (bone length vs. cranio-caudal diameter, bone length vs. dorso-ventral diameter), and of individual bone dimensions against estimated body mass, are compared to models of geometric and elastic similarity. The geometric similarity model describes the scaling relationship of bone length vs. cranio-caudal diameter and body mass vs. cranio-caudal diameter for the humerus only; geometric similarity also describes the scaling relationship of body mass vs. bone length for all three bones. None of the scaling relationships fits the elastic similarity model. The scaling relationships of bone length vs. dorso-ventral diameter for all three bones, and bone length vs. cranio-caudal diameter for the radius and ulna, exhibit negative allometry, indicating that large bones are less robust than small bones. Negative allometry of structural support elements has not been previously described for terrestrial mammals or plants. The high relative swimming speeds of small delphinids may generate sufficient stresses to require more robust bones relative to those of larger whales.
本研究考察了鲸类肱骨、桡骨和尺骨的异速生长比例关系。对20种齿鲸和3种须鲸的骨骼长度和直径进行了测量，这些鲸类代表了现存9个鲸类科中的8个科。将个体骨骼比例（骨骼长度与颅尾直径、骨骼长度与背腹直径）以及个体骨骼尺寸相对于估计体重的比例关系，与几何相似性和弹性相似性模型进行了比较。几何相似性模型仅描述了肱骨的骨骼长度与颅尾直径以及体重与颅尾直径的比例关系；几何相似性还描述了所有三块骨骼的体重与骨骼长度的比例关系。没有一种比例关系符合弹性相似性模型。所有三块骨骼的骨骼长度与背腹直径的比例关系，以及桡骨和尺骨的骨骼长度与颅尾直径的比例关系，均呈现负异速生长，表明大骨骼不如小骨骼粗壮。结构支撑元素的负异速生长此前在陆生哺乳动物或植物中尚未有过描述。小型海豚类较高的相对游泳速度可能会产生足够的应力，相对于大型鲸鱼而言，需要更粗壮的骨骼。
