Instituto de Herpetología, Fundación Miguel Lillo-CONICET, Tucumán, Argentina.
Anat Rec (Hoboken). 2010 Oct;293(10):1646-68. doi: 10.1002/ar.21212. Epub 2010 Jul 22.
Sesamoids are skeletal elements rarely considered in studies of the vertebrate skeleton. In this work, we integrate ontogenetic data of anuran sesamoids in two species (Leptodactylus latinasus and Pleurodema cf. guayapae), the related structures (tendons, muscles, and joints) in L. latinasus, and a survey of sesamoid distribution in 185 anuran taxa. Our main goals are: (1) to contribute to the knowledge of the comparative anatomy of sesamoids in tetrapods; (2) to provide additional developmental evidence to interpret the ontogenetic pattern of sesamoids in anurans, as a key to elucidate that of tetrapods in general; (3) to provide data about tendon development in relation to sesamoid development in anurans for the first time; and (4) to propose a pattern of anuran sesamoid distribution. The homologies of sesamoids across tetrapods are discussed here. Observations were made in cleared and stained skeletal whole-mounts. Fifty-four sesamoids were found in anurans, thirty-seven of which occur in L. latinasus. The traditional point of view of embedded sesamoids always resulting from biomechanical stimuli of a previously existing tendon is not sustained by our data. Many sesamoids arise before the differentiation of a tendinous tissue. Our survey results in a data set where the two big anuran clades, Hyloides (12 families) and Ranoides (14 families), were represented. The matrix has 38% missing entries. Most of the surveyed sesamoids have multiple origins, with only three of them (about 19%) having one origin.
籽骨是在研究脊椎动物骨骼时很少被考虑的骨骼元素。在这项工作中，我们整合了两种蛙类（Leptodactylus latinasus 和 Pleurodema cf. guayapae）的籽骨发育数据、L. latinasus 中相关结构（肌腱、肌肉和关节），以及对 185 种蛙类分类单元的籽骨分布的调查。我们的主要目标是：（1）为四肢动物籽骨的比较解剖学知识做出贡献；（2）提供额外的发育证据来解释蛙类籽骨的发育模式，作为阐明一般四足动物的关键；（3）首次提供有关蛙类肌腱发育与籽骨发育之间关系的数据；（4）提出蛙类籽骨分布模式。本文讨论了四足动物之间籽骨的同源性。观察结果来自于透明和染色的骨骼整体标本。在蛙类中发现了 54 块籽骨，其中 37 块存在于 L. latinasus 中。传统观点认为，嵌入式籽骨总是由先前存在的肌腱的生物力学刺激引起的，但我们的数据并不支持这一观点。许多籽骨在肌腱组织分化之前就出现了。我们的调查结果得到了一个数据集，其中包括两个大的蛙类分支，Hyloides（12 个科）和Ranoides（14 个科）。该矩阵有 38%的缺失条目。大多数被调查的籽骨有多个起源，只有三个（约 19%）有一个起源。
