Flexibility in starting posture drives flexibility in kinematic behavior of the kinethmoid-mediated premaxillary protrusion mechanism in a cyprinid fish, Cyprinus carpio
Flexibility in starting posture drives flexibility in kinematic behavior of the kinethmoid-mediated premaxillary protrusion mechanism in a cyprinid fish, Cyprinus carpio
复制标题
DOI：
10.1242/jeb.070516
复制
发表时间：
2012-07-01
影响因子：
2.8
通讯作者：
Hernandez, L. Patricia
中科院分区：
文献类型：
--
作者：
Gidmark, Nicholas J.;Staab, Katie Lynn;Hernandez, L. Patricia
鲤鱼的前颌骨突出涉及运动肌的旋转，运动肌是位于喙背中线的不成对的骨骼元件。没有肌肉直接插入动肌上，因此它的旋转一定是由其他骨骼的运动引起的。反过来，运动肌被认为会推动前上颌骨的上升过程，从而实现前突。为了确定运动样运动的原因和影响，我们使用 XROMM（运动形态的 X 射线重建）来测量鲤鱼 (Cyprinus carpio) 颅骨的运动学。前颌前突期间，平均动筛旋转为 83 度（3 人中有 18 次事件）。运动肌以与上颌桥的腹侧平移协调的方式旋转，并且这种腹侧平移可能主要由 A1 β 肌驱动。对灵活性（行为之间的变异性）和协调性（行为内骨骼之间的相关性）的分析表明，驱动前颌前突的是上颌桥的运动，而不是下颌的运动。因此，上颌突出与下颌凹陷分离，允许两种单独的突出模式：张嘴和闭嘴。这些行为具有不同的功能：分别是采购食物和分类食物。仅上颌骨起始姿势的变化就决定了进行哪种类型的前突；下游运动是不变的。对于闭合的嘴前突，腹侧移位的上颌起始姿势导致动筛旋转以产生更多腹侧定向的前上颌骨前突。这种灵活性是由动线-上颌桥-A1β机制赋予的，这是鲤鱼摄食机制中的几个进化新颖性之一，可能促成了这一物种谱系所特有的令人印象深刻的营养多样性。
Premaxillary protrusion in cypriniform fishes involves rotation of the kinethmoid, an unpaired skeletal element in the dorsal midline of the rostrum. No muscles insert directly onto the kinethmoid, so its rotation must be caused by the movement of other bones. In turn, the kinethmoid is thought to push on the ascending processes of the premaxillae, effecting protrusion. To determine the causes and effects of kinethmoid motion, we used XROMM (x-ray reconstruction of moving morphology) to measure the kinematics of cranial bones in common carp, Cyprinus carpio. Mean kinethmoid rotation was 83 deg during premaxillary protrusion (18 events in 3 individuals). The kinethmoid rotates in a coordinated way with ventral translation of the maxillary bridge, and this ventral translation is likely driven primarily by the A1 beta muscle. Analyses of flexibility (variability between behaviors) and coordination (correlation between bones within a behavior) indicate that motion of the maxillary bridge, not the lower jaw, drives premaxillary protrusion. Thus, upper jaw protrusion is decoupled from lower jaw depression, allowing for two separate modes of protrusion, open mouth and closed mouth. These behaviors serve different functions: to procure food and to sort food, respectively. Variation in starting posture of the maxilla alone dictates which type of protrusion is performed; downstream motions are invariant. For closed mouth protrusion, a ventrally displaced maxillary starting posture causes kinethmoid rotation to produce more ventrally directed premaxillary protrusion. This flexibility, bestowed by the kinethmoid-maxillary bridge-A1 beta mechanism, one of several evolutionary novelties in the cypriniform feeding mechanism, may have contributed to the impressive trophic diversity that characterizes this speciose lineage.