Comparative morphology of the humerus in forward-burrowing frogs
Comparative morphology of the humerus in forward-burrowing frogs
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DOI：
10.1093/biolinnean/blaa092
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发表时间：
2020-10-01
影响因子：
1.9
通讯作者：
Blackburn, David C.
中科院分区：
文献类型：
--
作者：
Keeffe, Rachel;Blackburn, David C.
穴居是青蛙（无尾目）的许多运动模式之一，在许多分支中发现。洞穴一般分为两类：前向洞穴和后向洞穴。虽然向前打洞比向后打洞更罕见，但我们发现它在无尾两栖动物中独立进化了至少8次，并且与外部和内部解剖结构的独特特征相关。肱骨的形状对于向前挖掘特别重要，因为许多物种使用前肢进行挖掘。使用X射线计算机断层扫描数据，我们的特点在肱骨的形状变化，包括三维（3D）形态测量，评估与这种变化在肱骨肌肉的形态，并讨论我们的结果的机械和进化的后果。我们发现，大多数向前穴居青蛙的肱骨在形态上不同于那些非向前穴居人，包括功能，如弯曲和厚骨干，存在一个明显的腹嵴，和相对较大的上髁和肱骨头。我们的研究结果还表明，胸肌解剖结构有很大的不同，在青蛙的穴居模式。这项工作提供了一个框架，预测运动模式的类群的自然历史是鲜为人知的，以及灭绝的类群。
Burrowing is one of the many locomotor modes of frogs (order Anura) and is found within many clades. Burrowing is generally categorized into two groups: forward-burrowing and backward-burrowing. While forward-burrowing is more rare than backward-burrowing, we show that it has evolved independently at least eight times across anurans and is correlated with distinct features of the external and internal anatomy. The shape of the humerus is especially important for forward-burrowing, as many species use their forelimbs for digging. Using X-ray computed tomography data, we characterize shape variation in the humerus, including three-dimensional (3D) morphometrics, assess the morphology of muscles related to this variation in the humerus, and discuss the mechanical and evolutionary consequences of our results. We show that the humeri of most forward-burrowing frogs are morphologically distinct from those of non-forward-burrowers, including features such as a curved and thick diaphysis, the presence of a pronounced ventral crest, and relatively large epicondyles and humeral head. Our findings also suggest that pectoral muscle anatomy differs substantially among burrowing modes in frogs. This work provides a framework for predicting locomotor modes in taxa for which the natural history is poorly known as well as extinct taxa.