Lauder George V
Department of Anatomy, University of Chicago, Chicago, Illinois 60637.
J Morphol. 1983 Oct;178(1):1-21. doi: 10.1002/jmor.1051780102.
The gross morphology and electrical activity of the muscles of the pharyngeal apparatus of centrarchid sunfishes (Lepomis) are analyzed within a monophyletic clade containing species specialized for snail-eating. Outgroup comparisons of both structure and activity patterns of muscles permit examination of the relationship between specialized diet and function of the trophic apparatus. In most sunfish species, electrical activity in the pharyngocleithralis internus muscle significantly overlaps that in the retractor dorsalis muscle during pharyngeal transport, indicating that the upper and lower pharyngeal jaws retract together. Activity in the pharyngohyoideus, levatores externi, and levator posterior also significantly overlaps activity of the retractor dorsalis. Snail-eating is associated with derived morphological, behavioral, and functional features. The shell is crushed before pharyngeal transport, correlated with extensive overlap in activity periods of muscles. One species, Lepomis microlophus, possesses a highly stereotyped neuromuscular repertoire that does not vary with prey type. All prey, even fish and worms, are subjected to crushing. Lepomis gibbosus exhibits the crushing pattern of muscle activity only when feeding on snails. L. microlophus has a hypertrophied levator posterior muscle, but the lines of action of the pharyngeal muscles are similar to the primitive condition. Pharyngeal transport in this species is unique in that activity of the pharyngocleithralis internus alternates with that of the retractor dorsalis. In sunfishes, alterations in the central control of peripheral structures have produced major changes in the sequence in which homologous components of the structural network are activated.
在一个包含以捕食蜗牛为特化特征的物种的单系类群中，对太阳鱼科太阳鱼（蓝鳃太阳鱼属）咽器官肌肉的大体形态和电活动进行了分析。通过对肌肉结构和活动模式的类群外比较，可以研究特化饮食与营养器官功能之间的关系。在大多数太阳鱼物种中，在咽运输过程中，咽内肌的电活动与背侧牵缩肌的电活动有显著重叠，这表明上、下咽颌一起回缩。咽舌骨肌、外提肌和后提肌的活动也与背侧牵缩肌的活动有显著重叠。捕食蜗牛与衍生的形态、行为和功能特征相关。在咽运输之前贝壳就被压碎，这与肌肉活动期的广泛重叠相关。一个物种，即小鳍蓝鳃太阳鱼，具有高度刻板的神经肌肉模式，不随猎物类型而变化。所有猎物，甚至是鱼类和蠕虫，都会被压碎。驼背太阳鱼只有在捕食蜗牛时才表现出肌肉活动的压碎模式。小鳍蓝鳃太阳鱼有一块肥大的后提肌，但其咽肌的作用线与原始状态相似。该物种的咽运输独特之处在于咽内肌的活动与背侧牵缩肌的活动交替进行。在太阳鱼中，外周结构中央控制的改变导致了结构网络同源成分激活顺序的重大变化。
