Setor de Mamíferos, Departamento de Vertebrados, Museu Nacional/UFRJ, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, RJ, CEP: 20940-040, Brazil.
Sci Rep. 2022 Jul 19;12(1):12293. doi: 10.1038/s41598-022-15952-7.
Mammals are generally brown in colour, but recent publications are showing that they may not be as uniform as once assumed. Monotremes, marsupials, and a handful of eutherians reflect various colours when lit with UV light, mostly purple. Because of these still scarce records, we aimed to explore UV reflectance among rodent genera, the most diverse mammalian group, and the group of eutherians with the most common records of biofluorescence. Here we report structures like nails and quills reflected green, but for most genera, it was faded. However, Hystrix, Erethizon, and Ctenomys showed intense and contrasting green glow, while Chaetomys presented a vivid orange anogenital. The main available explanation of fluorescence in mammals relies on porphyrin. This explanation applies to the cases like Chaetomys, where specimens showed anogenital orange biofluorescence, but does not apply to the green biofluorescence we observed. In our sample, because the structures that reflected green were all keratinized, we have reasons to believe that biofluorescence results from keratinization and is a structurally-based colouration. However, not all spines/quills equally biofluoresced, so we cannot rule out other explanations. Since Rodentia is the most common mammalian group with reports on biofluorescence, this trait likely serves various functions that match the species diversity of this group.
哺乳动物通常为棕色，但最近的出版物表明，它们可能并不像人们曾经认为的那样均匀。单孔目动物、有袋目动物和少数真兽类动物在被紫外线照射时会反射出各种颜色，主要是紫色。由于这些记录仍然很少，我们旨在探索最具多样性的哺乳动物群体——啮齿动物属和最常见生物荧光记录的真兽类动物的紫外线反射率。在这里，我们报告说像指甲和刚毛这样的结构反射出绿色，但对于大多数属来说，颜色已经褪色了。然而，豪猪、毛丝鼠和豚鼠表现出强烈而对比鲜明的绿色辉光，而Chaetomys 则呈现出鲜艳的橙色肛门生殖器。哺乳动物中荧光的主要解释依赖于卟啉。这种解释适用于像 Chaetomys 这样的情况，其中标本显示出肛门生殖器橙色生物荧光，但不适用于我们观察到的绿色生物荧光。在我们的样本中，由于反射绿色的结构都是角质化的，我们有理由相信生物荧光是由角质化产生的，是一种基于结构的着色。然而，并非所有的刺/刚毛都具有相同的生物荧光，因此我们不能排除其他解释。由于啮齿动物是最常见的具有生物荧光报告的哺乳动物群体，这种特征可能具有与该群体物种多样性相匹配的各种功能。
