García-Esponda César M, Candela Adriana M
Cátedra Zoología III Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de la Plata, Avenida 122 y 60, 1900 La Plata, Argentina.
CONICET, División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque, 1900 La Plata, Argentina.
Zoology (Jena). 2015 Jun;118(3):203-12. doi: 10.1016/j.zool.2014.12.006. Epub 2015 Apr 3.
Anatomical comparative studies including myological data of caviomorph rodents are relatively scarce, leading to a lack of use of muscular features in cladistic and morphofunctional analyses. In rodents, the hip adductor muscles constitute an important group of the hindlimb musculature, having an important function during the beginning of the stance phase. These muscles are subdivided in several distinct ways in the different clades of rodents, making the identification of their homologies hard to establish. In this contribution we provide a detailed description of the anatomical variation of the hip adductor muscle group of different genera of caviomorph rodents and identify the homologies of these muscles in the context of Rodentia. On this basis, we identify the characteristic pattern of the hip adductor muscles in Caviomorpha. Our results indicate that caviomorphs present a singular pattern of the hip adductor musculature that distinguishes them from other groups of rodents. They are characterized by having a single m. adductor brevis that includes solely its genicular part. This muscle, together with the m. gracilis, composes a muscular sheet that is medial to all other muscles of the hip adductor group. Both muscles probably have a synergistic action during locomotion, where the m. adductor brevis reinforces the multiple functions of the m. gracilis in caviomorphs. Mapping of analyzed myological characters in the context of Rodentia indicates that several features are recovered as potential synapomorphies of caviomorphs. Thus, analysis of the myological data described here adds to the current knowledge of caviomorph rodents from anatomical and functional points of view, indicating that this group has features that clearly differentiate them from other rodents.
包括豚鼠型啮齿动物肌肉学数据在内的解剖学比较研究相对较少，导致在支序分类和形态功能分析中缺乏对肌肉特征的应用。在啮齿动物中，髋内收肌是后肢肌肉组织的重要组成部分，在站立阶段开始时具有重要功能。这些肌肉在不同的啮齿动物类群中有几种不同的细分方式，使得它们的同源性难以确定。在本论文中，我们详细描述了豚鼠型啮齿动物不同属的髋内收肌群的解剖变异，并在啮齿目范围内确定了这些肌肉的同源性。在此基础上，我们确定了豚鼠型啮齿动物髋内收肌的特征模式。我们的结果表明，豚鼠型啮齿动物呈现出一种独特的髋内收肌模式，使其与其他啮齿动物类群区分开来。它们的特征是有一块单一的短内收肌，仅包括其膝部部分。这块肌肉与股薄肌一起构成了一个肌肉片，位于髋内收肌群所有其他肌肉的内侧。这两块肌肉在运动过程中可能具有协同作用，其中短内收肌增强了豚鼠型啮齿动物股薄肌的多种功能。在啮齿目范围内对分析的肌肉学特征进行绘图表明，有几个特征被发现是豚鼠型啮齿动物潜在的共有衍征。因此，对这里描述的肌肉学数据的分析从解剖学和功能角度增加了我们对豚鼠型啮齿动物的现有认识，表明该类群具有明显区别于其他啮齿动物的特征。
