Isotopic ordering in eggshells reflects body temperatures and suggests differing thermophysiology in two Cretaceous dinosaurs
Isotopic ordering in eggshells reflects body temperatures and suggests differing thermophysiology in two Cretaceous dinosaurs
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DOI：
10.1038/ncomms9296
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发表时间：
2015-10-01
影响因子：
16.6
通讯作者：
Eiler, John M.
中科院分区：
文献类型：
--
作者：
Eagle, Robert A.;Enriquez, Marcus;Eiler, John M.
我们对导致鸟类和哺乳动物现代吸热状态的进化转变的理解是不完整的，部分原因是可用于研究灭绝脊椎动物热生理学的工具有限。在这里，我们展示了卵壳的聚集同位素分析可以用来确定雌性在排卵期的体温。晚白垩世泰坦龙蛋壳体产生的温度与现代大型吸热系统相似。相比之下，猛禽卵壳产生的温度低于大多数现代吸热动物，但比共生的非生物成因碳酸盐高出约6摄氏度，这意味着这种分类群没有现代鸟类那样的体温调节，但能够将其身体温度提高到高于环境温度。因此，在所研究的物种中，我们没有观察到端元外温或吸热的有力证据。这两个物种的体温表明，非鸟类恐龙中可能存在可变的体温调节，并不是所有恐龙的体温都在现代鸟类的体温范围内。
Our understanding of the evolutionary transitions leading to the modern endothermic state of birds and mammals is incomplete, partly because tools available to study the thermophysiology of extinct vertebrates are limited. Here we show that clumped isotope analysis of eggshells can be used to determine body temperatures of females during periods of ovulation. Late Cretaceous titanosaurid eggshells yield temperatures similar to large modern endotherms. In contrast, oviraptorid eggshells yield temperatures lower than most modern endotherms but similar to 6 degrees C higher than co-occurring abiogenic carbonates, implying that this taxon did not have thermoregulation comparable to modern birds, but was able to elevate its body temperature above environmental temperatures. Therefore, we observe no strong evidence for end-member ectothermy or endothermy in the species examined. Body temperatures for these two species indicate that variable thermoregulation likely existed among the non-avian dinosaurs and that not all dinosaurs had body temperatures in the range of that seen in modern birds.