ABSTRACT Wormian bones are accessory bones found between cranial elements. These rare bones vary greatly in size, shape and placement. Wormian bones are well-known in mammals, notably in humans and chimpanzees, but not in lizards. Here we examine the genus Zygaspis, a southern African amphisbaenian with complex cranial sutures, for the presence of Wormian bones. Skulls from seven of the eight species of Zygaspis were examined for the presence of Wormian bones. Because of their small size, complex sutures and delicate nature, high-resolution X-ray computed tomography was used to produce 3D models of the skulls. We discovered three Wormian bones in the interdigitated frontoparietal suture of Z. kafuensis. This discovery is the first known record of Wormian bones in a lizard and it is one of the few reports of them in the Squamata. The presence of Wormian bones in a head-first, burrowing squamate allows for a possible functional role to be hypothesised. Additional studies on a variety of squamate taxa are now needed, particularly in burrowing groups with interdigitated sutures, to improve our understanding of these rare cranial elements.

中文翻译：

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蜥蜴中蠕虫骨骼的第一个记录

摘要蠕虫骨是在颅骨之间发现的副骨。这些稀有骨头的大小、形状和位置差异很大。蠕虫骨骼在哺乳动物中是众所周知的，尤其是在人类和黑猩猩中，但在蜥蜴中则不然。在这里，我们检查了 Zygaspis 属，这是一种具有复杂颅缝的南部非洲两栖动物，是否存在蠕虫骨骼。检查了八种 Zygaspis 中七种的头骨是否存在蠕虫骨骼。由于其体积小、缝合复杂且性质精致，高分辨率 X 射线计算机断层扫描被用于生成头骨的 3D 模型。我们在 Z. kafuensis 的指状额顶缝中发现了三个蠕虫骨。这一发现是第一个已知的蜥蜴中蠕虫骨骼的记录，也是有鳞蜥蜴中为数不多的关于蠕虫骨骼的报道之一。蠕虫骨头在头朝下、挖洞的有鳞动物中的存在允许假设可能的功能作用。现在需要对各种有鳞类群进行更多研究，特别是在具有指状缝合线的穴居类群中，以提高我们对这些稀有颅骨元素的理解。