Preserved melanin pigments have been discovered in fossilised integumentary appendages of several amniote lineages (fishes, frogs, snakes, marine reptiles, non‐avialan dinosaurs, birds, and mammals) excavated from lagerstätten across the globe. Melanisation is a leading factor in organic integument preservation in these fossils. Melanin in extant vertebrates is typically stored in rod‐ to sphere‐shaped, lysosome‐derived, membrane‐bound vesicles called melanosomes. Black, dark brown, and grey colours are produced by eumelanin, and reddish‐brown colours are produced by phaeomelanin. Specific morphotypes and nanostructural arrangements of melanosomes and their relation to the keratin matrix in integumentary appendages create the so‐called 'structural colours'. Reconstruction of colour patterns in ancient animals has opened an exciting new avenue for studying their life, behaviour and ecology. Modern relationships between the shape, arrangement, and size of avian melanosomes, melanin chemistry, and feather colour have been applied to reconstruct the hues and colour patterns of isolated feathers and plumages of the dinosaurs Anchiornis, Sinosauropteryx, and Microraptor in seminal papers that initiated the field of palaeocolour reconstruction. Since then, further research has identified countershading camouflage patterns, and informed subsequent predictions on the ecology and behaviour of these extinct animals. However, palaeocolour reconstruction remains a nascent field, and current approaches have considerable potential for further refinement, standardisation, and expansion. This includes detailed study of non‐melanic pigments that might be preserved in fossilised integuments. A common issue among existing palaeocolour studies is the lack of contextualisation of different lines of evidence and the wide variety of techniques currently employed. To that end, this review focused on fossil amniotes: (i) produces an overarching framework that appropriately reconstructs palaeocolour by accounting for the chemical signatures of various pigments, morphology and local arrangement of pigment‐bearing vesicles, pigment concentration, macroscopic colour patterns, and taphonomy; (ii) provides background context for the evolution of colour‐producing mechanisms; and (iii) encourages future efforts in palaeocolour reconstructions particularly of less‐studied groups such as non‐dinosaur archosaurs and non‐archosaur amniotes.

中文翻译：

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羊膜古颜色重建的最新进展和未来研究的框架

在全球各地的拉格斯塔滕出土的几种羊膜动物谱系（鱼、青蛙、蛇、海洋爬行动物、非鸟类恐龙、鸟类和哺乳动物）的外皮附属物化石中发现了保存完好的黑色素。黑化是这些化石中有机外皮保存的主要因素。现存脊椎动物中的黑色素通常储存在棒状至球状、溶酶体衍生的、膜结合的囊泡中，称为黑素体。黑色、深棕色和灰色是由真黑素产生的，红棕色是由褐黑素产生的。黑素体的特定形态和纳米结构排列及其与外皮附属物中角蛋白基质的关系创造了所谓的“结构颜色”。古代动物颜色模式的重建为研究它们的生活、行为和生态开辟了一条令人兴奋的新途径。鸟类黑色素体的形状、排列和大小、黑色素化学和羽毛颜色之间的现代关系已被应用于重建近鸟龙、中华龙鸟和小盗龙的孤立羽毛和恐龙羽毛的色调和颜色图案，这些论文开创了古色彩重建领域。从那时起，进一步的研究确定了反阴影伪装模式，并为随后对这些灭绝动物的生态和行为的预测提供了信息。然而，古颜色重建仍然是一个新兴领域，当前的方法具有进一步完善、标准化和扩展的巨大潜力。这包括对可能保存在化石外皮中的非黑色素的详细研究。现有古颜色研究的一个常见问题是缺乏不同证据线的背景和目前使用的各种技术。为此，本综述重点关注羊膜动物化石：（i）产生一个总体框架，通过考虑各种色素的化学特征、承载色素的囊泡的形态和局部排列、色素浓度、宏观颜色图案和埋藏学；(ii) 为颜色产生机制的演变提供背景知识；(iii) 鼓励未来在古颜色重建方面做出努力，特别是研究较少的群体，如非恐龙祖龙和非祖龙羊膜动物。