Van Damme J, Aerts P
Department of Biology, University of Antwerp, Belgium.
J Morphol. 1997 Aug;233(2):113-25. doi: 10.1002/(SICI)1097-4687(199708)233:2<113::AID-JMOR3>3.0.CO;2-7.
Head kinematics during aquatic feeding of the Australian long-necked turtle (Chelodina) were studied by means of high speed video recordings. Buccal expansion was assessed by calculation of elliptical cross-sectional surfaces. Further, displacements of head, carapace, and prey in the earth bound frame, of the prey relative to the center of the gape, and of the head relative to the carapace were determined. Rates of change (velocities) of all these variables were calculated. These data are combined with information on the osteology and myology of the head. The robust development of the large hyobranchial apparatus, the massive intercornuatus muscle, and the presence of the branchiosquamosus muscle were related to aquatic feeding skills. Head kinematics are variable in amplitude and relative timing, but proceed always in a rostrocaudal sequence. According to their effect on the prey, two components are distinguished in the process of expansion. The first compensates for head/body movements (compensatory suction). The second causes distinct acceleration of water and prey (inertial suction). The latter component is mainly driven by the abduction of the second branchial arch. In spite of largely different structural solutions, optimal feeding conditions as deduced for suction in feeding fishes are also employed by Chelodina. This further promotes the assumption that hydrodynamics constrain evolutive solutions for aquatic feeding.
通过高速视频记录研究了澳大利亚长颈龟（Chelodina）在水生摄食过程中的头部运动学。通过计算椭圆形横截面来评估颊部扩张。此外，还确定了在地面坐标系中头部、背甲和猎物的位移，猎物相对于口角中心的位移，以及头部相对于背甲的位移。计算了所有这些变量的变化率（速度）。这些数据与头部骨骼学和肌肉学的信息相结合。大型舌骨器的强健发育、巨大的角间肌以及鳃鳞肌的存在与水生摄食技能有关。头部运动学在幅度和相对时间上是可变的，但总是按头尾顺序进行。根据其对猎物的影响，在扩张过程中可区分出两个组成部分。第一个补偿头部/身体运动（补偿性吸力）。第二个导致水和猎物明显加速（惯性吸力）。后一个组成部分主要由第二鳃弓的外展驱动。尽管结构解决方案有很大不同，但Chelodina也采用了为鱼类摄食中的吸力推导出来的最佳摄食条件。这进一步支持了流体动力学限制水生摄食进化解决方案的假设。
