Soares Mateus C, de Carvalho Marcelo R
Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Trav. 14, no. 101, São Paulo, 05508-090, SP, Brazil.
J Morphol. 2013 Oct;274(10):1111-23. doi: 10.1002/jmor.20166. Epub 2013 Jun 26.
The superorder Galeomorph comprises the orders Heterodontiformes, Orectolobiformes, Lamniformes, and Carcharhiniformes. Recent morphological and molecular support that it is a monophyletic taxon. The phyletic relationship within the Galeomorphi are also well resolved. However, only few morphological characters of the mandibular and hyoid muscles have been employed, and a detailed description of these muscles and their variations may contribute new interpretations of homology and to the discussion of different hypothesis of intrarelationships. This paper provides a detailed description of mandibular and hyoid arch muscles in galeomorph sharks, within a comparative elasmobranch framework, with the objective to discuss putative homologies that may elucidate our understanding of galeomorph evolution. Twenty-eight galeomorph species were dissected, described, illustrated and compared with other elasmobranchs and with data from the literature. The Galeomorphi are supported as monophyletic by presenting the m. levator labii superioris attached directly to the neurocranium, different from the attachment through a tendon in basal squalomorphs. Heterodontiformes and Orectolobiformes share particular variations in the position and insertion of the m. levator labii superioris and the presence of a well-defined m. levator hyomandibulae. Lamniformes and Carcharhiniformes show similar patterns in the position and attachment of the m. levator labii superioris, subdivision of the m. adductor mandibulae, and the presence of an almost indivisible m. levator hyomandibulae and m. constrictor hyoideus dorsalis, similar to the condition, albeit independently, in basal squalomorphs. No specific mandibular or hyoid arch muscle character was found to support the clade composed of Orectolobiformes, Lamniformes, and Carcharhiniformes, as advocated by recent phylogenetic analyses.
真鲨总目包括异齿鲨目、须鲨目、鼠鲨目和真鲨目。近期的形态学和分子学研究支持其为单系类群。真鲨总目内部的系统发育关系也已得到很好的解析。然而，下颌肌和舌骨肌仅采用了少数形态学特征，对这些肌肉及其变异的详细描述可能有助于对同源性的新解释以及对内部关系不同假说的讨论。本文在比较板鳃亚纲的框架内，对真鲨总目鲨鱼的下颌肌和舌骨弓肌进行了详细描述，目的是讨论可能阐明我们对真鲨总目进化理解的假定同源性。解剖、描述、图示了28种真鲨总目物种，并与其他板鳃亚纲动物以及文献数据进行了比较。真鲨总目被认为是单系的，因为其上唇提肌直接附着于脑颅，这与基干角鲨总目的通过肌腱附着不同。异齿鲨目和须鲨目在上唇提肌的位置和附着点以及明确的舌骨提肌的存在方面具有特定的变异。鼠鲨目和真鲨目在上唇提肌的位置和附着、咬肌的细分以及几乎不可分割的舌骨提肌和背侧舌骨缩肌的存在方面表现出相似的模式，这与基干角鲨总目的情况相似，尽管是独立出现的。未发现特定的下颌或舌骨弓肌特征支持近期系统发育分析所主张的由须鲨目、鼠鲨目和真鲨目组成的类群。
