Department of Herpetology, Zoologische Staatssammlung München (ZSM-SNSB), Münchhausenstr. 21, 81247, München, Germany.
Department Biologie II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany.
Sci Rep. 2018 Jan 15;8(1):698. doi: 10.1038/s41598-017-19070-7.
Fluorescence is widespread in marine organisms but uncommon in terrestrial tetrapods. We here show that many chameleon species have bony tubercles protruding from the skull that are visible through their scales, and fluoresce under UV light. Tubercles arising from bones of the skull displace all dermal layers other than a thin, transparent layer of epidermis, creating a 'window' onto the bone. In the genus Calumma, the number of these tubercles is sexually dimorphic in most species, suggesting a signalling role, and also strongly reflects species groups, indicating systematic value of these features. Co-option of the known fluorescent properties of bone has never before been shown, yet it is widespread in the chameleons of Madagascar and some African chameleon genera, particularly in those genera living in forested, humid habitats known to have a higher relative component of ambient UV light. The fluorescence emits with a maximum at around 430 nm in blue colour which contrasts well to the green and brown background reflectance of forest habitats. This discovery opens new avenues in the study of signalling among chameleons and sexual selection factors driving ornamentation.
荧光在海洋生物中很常见，但在陆生四足动物中却很少见。我们在这里表明，许多变色龙物种的头骨上有骨性结节突出，这些结节在紫外线照射下是可见的。头骨上的骨结节会将所有真皮层都推离，除了一层薄薄的透明表皮，从而在骨头上形成一个“窗口”。在 Calumma 属中，大多数物种的这些结节在性别上存在二态性，这表明它们具有信号作用，而且还强烈反映了物种群体，表明这些特征具有系统学价值。骨的已知荧光特性以前从未被证明过，但在马达加斯加的变色龙和一些非洲变色龙属中却广泛存在，特别是在那些生活在森林茂密、潮湿的栖息地的属中，这些栖息地已知具有较高的环境紫外线相对成分。荧光在蓝色中发出最大峰值约为 430nm，与森林栖息地的绿色和棕色背景反射形成鲜明对比。这一发现为研究变色龙之间的信号传递和驱动装饰的性选择因素开辟了新的途径。
