Department of Zoology, Faculty of Science, Charles University, 128 43, Prague, Czech Republic.
Department of Anatomy, Third Faculty of Medicine, Charles University, 100 00, Prague, Czech Republic.
Sci Rep. 2023 Apr 19;13(1):6405. doi: 10.1038/s41598-023-33244-6.
Osteoderms, also called dermal armour, often play a role in predator defence. The presence of osteoderms is highly irregularly distributed across the squamate phylogeny and they have not been found in snakes. In this study, we searched for candidate snake species that would benefit from such armour to protect their body, focusing primarily on fossorial species with defensive tail displays. We examined the tail morphology of 27 snake species from different families using micro-computed tomography (µCT) and micro- radiography. We discovered dermal armour in four species of sand boas (Erycidae) that also feature enlarged and highly modified caudal vertebrae. This is the first description of dermal armour in snakes. Ancestral state reconstructions revealed that osteoderms likely evolved once or multiple times in Erycidae. We have not found osteoderms in any other examined snake species. Nevertheless, similar structures are known from unrelated squamate clades, such as gerrhosaurids and geckos. This supports the idea of underlying deep developmental homology. We propose the hypothesis that osteoderms protect sand boas like the "brigandine armour" of medieval warriors. We interpret it as another component of the sand boas' rich defence strategy.
骨板，也称为真皮装甲，通常在防御捕食者方面发挥作用。骨板在有鳞目系统发育中分布高度不规则，在蛇类中尚未发现。在这项研究中，我们寻找可能受益于这种装甲来保护身体的候选蛇种，主要关注具有防御性尾部展示的穴居物种。我们使用微计算机断层扫描（µCT）和微射线照相术检查了来自不同科的 27 种蛇的尾巴形态。我们在四种沙蟒（Erycidae）中发现了真皮装甲，它们的尾椎骨也被放大并高度特化。这是蛇类中真皮装甲的首次描述。祖先状态重建表明，骨板可能在 Erycidae 中进化了一次或多次。我们在任何其他检查过的蛇种中都没有发现骨板。然而，类似的结构在无亲缘关系的有鳞目类群中是已知的，例如鬣蜥和壁虎。这支持了深层发育同源性的观点。我们提出了这样的假设：骨板像中世纪战士的“板甲”一样保护沙蟒。我们将其解释为沙蟒丰富防御策略的另一个组成部分。
