About 300 valid species are classified within the order Rajiformes, the largest group of chondrichthyans. The monophyly of this order is highly supported by morphological and molecular inferences, but little is known about the mandibular, hyoid, and hypobranchial muscles of its members. This study aims to describe and illustrate the morphological variation in mandibular, hyoid, and hypobranchial muscles among rajiforms, review their terminology and discuss the phylogenetic and functional implications of conditions observed. Twenty-two ethanol-preserved specimens belonging to 19 of the 36 skate genera currently considered valid were manually dissected. Nine new characters are proposed and tested cladistically. The main differences observed are the relative width of muscle units of the levator palatoquadrati, insertion point and extension of the intermanibularis posterior, relative position of the facialis nerve and the levator hyomandibularis muscle, origin and insertion of the coracomandibularis, extension of the coracohyomandibularis, and occurrence of the preorbitalis medialis and intermandibularis anterior. When analysed together with other morphological features, muscle characters have shown to play a key role in the understanding of interrelationships among skates. Nevertheless, additional studies are needed to improve our knowledge of rajiform systematics and the functionality of mandibular, hyoid, and hypobranchial muscles.

中文翻译：

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溜冰鞋的下颌骨、舌骨和下鳃肌肉组织（软骨鱼类：Batoidea：Rajiformes）：修订后的术语和系统发育意义


大约 300 个有效物种被归类为 Rajiformes，这是最大的软骨鱼类群。该目 Monophy 得到了形态学和分子推断的高度支持，但对其成员的下颌肌、舌骨肌和下鳃肌知之甚少。本研究旨在描述和说明鞭形目中下颌肌、舌骨肌和下鳃肌的形态变化，回顾它们的术语并讨论观察到的条件的系统发育和功能意义。对目前被认为有效的 36 个鳐鱼属中的 19 个乙醇保存的标本进行了人工解剖。提出了九个新字符并进行了分类测试。观察到的主要差异是腭方提肌肌肉单位的相对宽度、下颌内肌后部的插入点和延伸、面神经和舌下颌提肌的相对位置、喙下颌肌的起源和插入、喙骨下颌肌的延伸以及眶前内侧肌和前下颌肌的发生。当与其他形态特征一起分析时，肌肉特征已被证明在理解溜冰鞋之间的相互关系中起着关键作用。尽管如此，还需要更多的研究来提高我们对拉氏样系统学以及下颌肌、舌骨和下鳃肌功能的了解。