Evolutionary transitions in temporal niche necessitates specialized morphology, physiology, and behaviors. Diurnal, heliothermic squamates (lizards and snakes) that bask require protection from ultraviolet radiation (UV) that can damage internal organs such as the brain, viscera, and gonads. Many smaller squamates have accomplished this protection by hyperpigmentation of the peritoneum and subcutaneous dorsum. Typically, nocturnal species do not require these protections from ultraviolet light. However, some nocturnal species that exhibit extreme crypsis may be exposed to sunlight and UV and require some means of mediating that damage. One such species is Gekko (Ptychozoon) kuhli, a nocturnal, arboreal gecko that uses extreme crypsis to blend in with tree bark. Hiding motionless on tree trunks leaves geckos exposed to sunlight during the day. Thus, we predict that G. kuhli will have independently evolved a hyperpigmented phenotype. To investigate this hypothesized association between temporal niche, behavior, and morphology, we characterized adult subcutaneous pigment for eight gecko species and embryonic pigment accumulation for a subset of four of these species, exhibiting diverse temporal niche and thermoregulatory behaviors. We predicted that nocturnal/potentially-heliothermic G. kuhli would exhibit hyperpigmentation of internal structures like that of diurnal/heliothermic geckos. We further predicted that embryonic pigment accumulation of G. kuhli would resemble that of diurnal/heliothermic as opposed to nocturnal/thigmothermic geckos. We found that temporal niche and thermoregulatory behavior predicted the degree of subcutaneous pigment in the eight gecko species examined. We demonstrate that G. kuhli accumulates pigment extremely early in embryonic development, unlike a diurnal/heliothermic gecko species, despite having a similar adult phenotype. The evolution of hyperpigmentation in G. kuhli is likely an adaptation to limit damage from occasional daytime UV exposure caused by crypsis-associated basking behavior. Gekko kuhli achieves its hyperpigmented phenotype through a derived developmental pattern, not seen in any other lizard species investigated to date, suggesting novel temporal differences in the migration and/or differentiation of reptilian neural crest derivatives.

中文翻译：

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夜间和日间壁虎之间的收敛性色素沉着过度是色素发育的不同模式（鳞状：Gekkota）。

时间生态位的进化转变需要特殊的形态，生理学和行为。晒日光浴的鳞状蜥蜴（蜥蜴和蛇）需要受到紫外线保护，以免破坏大脑，内脏和性腺等内脏器官。许多较小的鳞状细胞已通过腹膜和皮下背部色素沉着过度实现了这种保护。通常，夜间物种不需要紫外线保护。但是，某些表现出极端低温的夜间物种可能会暴露在阳光和紫外线下，并需要一些媒介来解决这种损害。一种这样的物种是Gekko（Ptychozoon）kuhli，它是一种夜间的树栖壁虎，它使用极端的低温真菌与树皮融合在一起。躲在树干上一动不动，使壁虎白天暴露在阳光下。从而，我们预测G. kuhli将独立进化出色素沉着的表型。为了调查这种假设的时间生态位，行为和形态之间的联系，我们表征了八种壁虎物种的成年皮下色素和其中四个物种的子集的胚胎色素积聚，表现出不同的时间生态位和温度调节行为。我们预测夜间/潜在发热的G. kuhli会表现出内部结构的色素沉着，如昼夜/发热的壁虎。我们进一步预测，G。kuhli的胚胎色素积聚类似于昼夜/体温升高的壁虎，与昼夜/体温升高的壁虎相似。我们发现，时间上的利基和温度调节行为预测了所检查的八个壁虎物种中皮下色素的程度。我们证明G. kuhli在胚胎发育中极早地积累色素，与昼夜/热温壁虎物种不同，尽管它具有相似的成年表型。G. kuhli色素沉着过度的演变很可能是一种适应措施，以限制因与低温相关的取暖行为而导致的日间紫外线暴露而造成的损害。Gekko kuhli通过衍生的发育模式实现了色素沉着的表型，这在迄今为止研究的任何其他蜥蜴物种中都未见，这表明爬行动物神经c衍生物的迁移和/或分化具有新的时间差异。kuhli可能是一种适应措施，可以限制因与低温相关的晒日光行为而导致的日间紫外线暴露对人体的伤害。Gekko kuhli通过衍生的发育模式实现了色素沉着的表型，这在迄今为止研究的任何其他蜥蜴物种中都未见，这表明爬行动物神经til衍生物的迁移和/或分化具有新的时间差异。kuhli可能是一种适应措施，可以限制因与低温相关的晒日光行为而导致的日间紫外线暴露对人体的伤害。Gekko kuhli通过衍生的发育模式实现了色素沉着的表型，这在迄今为止研究的任何其他蜥蜴物种中都未见，这表明爬行动物神经til衍生物的迁移和/或分化具有新的时间差异。