Evolutionary transformation of the palmaris longus muscle in flying squirrels (Pteromyini: Sciuridae): An anatomical consideration of the origin of the uniquely specialized styliform cartilage.
Evolutionary transformation of the palmaris longus muscle in flying squirrels (Pteromyini: Sciuridae): An anatomical consideration of the origin of the uniquely specialized styliform cartilage.
复制标题
飞鼠掌长肌的进化转变（Pteromyini：Sciuridae）：对独特的专门的针状软骨起源的解剖学考虑。
DOI：
10.1002/ar.23471
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发表时间：
2017
影响因子：
--
通讯作者：
Sato F
中科院分区：
文献类型：
--
作者：
Kawashima T;Thorington RW Jr.;Bohaska PW;Sato F
松鼠进化和发育中的一个长期存在的问题是飞鼠的茎状软骨的起源，它从腕骨横向延伸以支撑滑动膜（翼膜）。由于茎突软骨是允许滑行运动的独特专门结构之一，因此了解其起源和周围变形是了解其空气动力学演变的关键。由于胚胎学材料的稀少，明确回答这个问题的发育研究将是困难的。相反，解剖学研究提出了两个关于茎突软骨同源性的主要假设：其他哺乳动物的豌豆骨，或额外的腕骨结构，如其他哺乳动物的尺骨籽骨或非滑动松鼠的小鱼际软骨。为了验证这些假设，对滑翔和非滑翔松鼠以及猫猴的腕骨进行了详细的解剖检查。通过对飞鼠腕骨的物理解剖和虚拟解剖，发现飞鼠腕骨中同时存在豌豆骨和茎突软骨。这一发现进一步支持了一个“真正的掌长肌”，与神经支配的典型肌肉，插入在茎突软骨。总之，我们的骨骼学、肌肉学和神经学结果表明，在飞鼠中，茎突软骨从最初的浅表和尺骨来源的原基转化为目前的形式。Anat Rec，300：340-352，2017。© 2016 Wiley Periodicals，Inc.
A long‐standing issue in squirrel evolution and development is the origin of the styliform cartilage of flying squirrels, which extends laterally from the carpus to support the gliding membrane (patagium). Because the styliform cartilage is one of the uniquely specialized structures permitting gliding locomotion, the knowledge of its origin and surrounding transformation is key for understanding their aerodynamic evolution. The developmental study that would definitely answer this question would be difficult due to the rarity of embryological material. Instead, anatomical examinations have suggested two major hypotheses on the homology of the styliform cartilage: the pisiform bone of other mammals, or an additional carpal structure, such as the ulnar sesamoid of some of the other mammals or the hypothenar cartilage of the non‐gliding squirrels. To test these hypotheses, a detailed examination of the anatomy of the carpus of gliding and non‐gliding squirrels, and the colugo were undertaken. Based on physical and virtual dissections of the carpus, this study showed that both the pisiform bone and styliform cartilage were present in flying squirrels. This finding is further supported by demonstration that a “true Palmaris longus,” with innervation typical for this muscle, inserts on the styliform cartilage. Taken together, our osteological, muscular, and neurological results suggest that the styliform cartilage was transformed in flying squirrels from an initially superficial and ulnar‐derived anlagen into its current form. Anat Rec, 300:340–352, 2017. © 2016 Wiley Periodicals, Inc.