Pterins are one of the major sources of bright coloration in animals. They are produced endogenously, participate in vital physiological processes and serve a variety of signalling functions. Despite their ubiquity in nature, pterin-based pigmentation has received little attention when compared to other major pigment classes. Here, we summarize major aspects relating to pterin pigmentation in animals, from its long history of research to recent genomic studies on the molecular mechanisms underlying its evolution. We argue that pterins have intermediate characteristics (endogenously produced, typically bright) between two well-studied pigment types, melanins (endogenously produced, typically cryptic) and carotenoids (dietary uptake, typically bright), providing unique opportunities to address general questions about the biology of coloration, from the mechanisms that determine how different types of pigmentation evolve to discussions on honest signalling hypotheses. Crucial gaps persist in our knowledge on the molecular basis underlying the production and deposition of pterins. We thus highlight the need for functional studies on systems amenable for laboratory manipulation, but also on systems that exhibit natural variation in pterin pigmentation. The wealth of potential model species, coupled with recent technological and analytical advances, make this a promising time to advance research on pterin-based pigmentation in animals.

蝶呤是动物鲜艳色彩的主要来源之一。它们是内源性产生的，参与重要的生理过程并发挥多种信号功能。尽管在自然界中普遍存在，但与其他主要色素类别相比，基于蝶呤的色素沉着很少受到关注。在这里，我们总结了与动物蝶呤色素沉着相关的主要方面，从其悠久的研究历史到最近对其进化分子机制的基因组研究。我们认为，蝶呤具有介于两种经过充分研究的色素类型——黑色素（内源产生，通常神秘）和类胡萝卜素（饮食摄取，通常明亮）之间的中间特征（内源产生，通常明亮），为解决有关生物学的一般问题提供了独特的机会。从决定不同类型色素沉着如何演变的机制到对诚实信号假设的讨论。我们对蝶呤产生和沉积的分子基础的认识仍然存在重大差距。因此，我们强调需要对适合实验室操作的系统进行功能研究，而且还需要对蝶呤色素沉着表现出自然变化的系统进行功能研究。丰富的潜在模型物种，加上最新的技术和分析进展，使得现在成为推进基于蝶呤的动物色素沉着研究的大好时机。