Convergence in morphology and masticatory function between the pharyngeal jaws of grass carp, Ctenopharyngodon idella, and oral jaws of amniote herbivores
Convergence in morphology and masticatory function between the pharyngeal jaws of grass carp, Ctenopharyngodon idella, and oral jaws of amniote herbivores
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DOI：
10.1242/jeb.096248
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发表时间：
2014-06-01
影响因子：
2.8
通讯作者：
Brainerd, Elizabeth L.
中科院分区：
文献类型：
--
作者：
Gidmark, Nicholas J.;Tarrant, James C.;Brainerd, Elizabeth L.
保护植物细胞的富含纤维素的细胞壁难以消化，因此机械食物加工是脊椎动物草食性的一个关键方面。作为复杂、有节奏的咀嚼行程的一部分，细胞壁通常通过咬合面中扁平牙齿的平移（即磨削）而被破坏。草鱼（Ctenopharyngodon idella）是一种贪婪的入侵性草食性鱼类，完全依靠位于喉咙后部的咽齿对植物材料进行机械加工。在这里，我们描述了草鱼咽颌的肌肉骨骼解剖结构，并使用 XROMM 来量化咀嚼运动学和肌肉拉伤。咽颌悬挂在由 11 块肌肉组成的吊带中，与头部的任何其他骨骼元件不保持骨关节。颌骨上有长而锯齿状的牙齿，这些牙齿在使用过程中会磨损成扁平的齿尖。我们的运动学数据表明，这种磨损是牙齿抬高至枕骨突和角质咀嚼垫咬合的结果，而不是牙齿咬合的结果。咽颌抬高是由于提颌肌（提肌弓 V）的巨大拉力导致的，该肌肉驱动类似滑轮的机构，使颌绕左、右咽颌之间联合处的枢轴点旋转。在整个咬合阶段，这些复杂、有节奏的颌部旋转使牙齿横向平移穿过咀嚼表面。草鱼的咀嚼系统在总体形态和咀嚼功能上与其他脊椎动物的草食性咀嚼策略惊人地相似。
The cellulose-rich walls that protect plant cells are difficult to digest, and therefore mechanical food processing is a key aspect of herbivory across vertebrates. Cell walls are typically broken down by translation of flattened teeth in the occlusal plane (i.e. grinding) as part of a complex, rhythmic chewing stroke. The grass carp, Ctenopharyngodon idella, is a voracious, invasive herbivorous fish that relies solely on its pharyngeal teeth, located in the back of the throat, for mechanical processing of plant material. Here, we describe the musculoskeletal anatomy of the pharyngeal jaws of grass carp and use XROMM to quantify chewing kinematics and muscle strain. The pharyngeal jaws are suspended in a sling of 11 muscles and maintain no bony articulation with any other skeletal elements in the head. The jaws bear long, serrated teeth that are worn during use into flattened tooth cusps. Our kinematic data show that this wear is the result of the teeth being elevated into occlusion against the basioccipital process and keratinous chewing pad, not tooth-on-tooth occlusion. Pharyngeal jaw elevation results from large strains in the jaw elevator muscle, the levator arcus branchialis V, to drive a pulley-like mechanism that rotates the jaws about a pivot point at the symphysis between the left and right pharyngeal jaws. These complex, rhythmic jaw rotations translate the teeth laterally across the chewing surface throughout the occlusion phase. The grass carp chewing system is strikingly similar in gross morphology and masticatory function to herbivorous chewing strategies in other vertebrates.