Until now, no such hatchlings had been found, and the only known polar dinosaur eggs were from the Kakanaut formation of north-eastern Russia, which was only just within the Arctic Circle when its rocks were laid down. Dr Druckenmiller's discoveries are from the Prince Creek Formation of northern Alaska, which may have been as close as 5° of latitude from the North Pole when its rocks formed 70m years ago.
到目前為止,還沒有發現這樣的小恐龍,唯一已知的極地恐龍蛋來自俄羅斯東北部的Kakanaut地層,當巖石被埋下時,該地層剛好位于北極圈內。德魯肯米勒博士的發現來自阿拉斯加北部的普林斯克里克地層,那里的巖石在形成于7000萬年前時可能距離北極的緯度只有5°。
The fossils themselves come from a range of dinosaur groups, including ceratopsians (related to the likes of Triceratops), duck-billed hadrosaurs, large carnivores related to Tyrannosaurus and smaller velociraptor-like predators. This suggests a diverse and flourishing ecosystem, despite the fact that Prince Creek was continuously dark for 120 days a year and had an average annual temperature of 6°C—meaning snow would have been common in winter.
這些化石本身來自一系列的恐龍群,包括角鼻龍(與三角龍之類的恐龍有親緣關系)、鴨嘴龍、與霸王龍有親緣關系的大型食肉動物以及小型的類似迅猛龍的食肉動物,展現了一個多樣化的、繁榮的生態系統,盡管普林斯溪一年中有120天一直處于黑暗之中,而且年平均溫度為6°C——這意味著冬季降雪頻繁。
How all these creatures survived those conditions was, Dr Druckenmiller suggests, a consequence of dinosaurs' warmbloodedness and the downy feathers many of them are now known to have sported. No direct evidence of feathers has yet been found among the Alaskan fossils, but their ubiquity elsewhere makes it likely they had them.
德魯肯米勒博士認為,所有這些生物之所以能在這樣的環境中生存下來,是因為恐龍是溫血動物,而且現在我們知道,恐龍中有許多都長有蓬松的羽毛。雖然目前在阿拉斯加化石中還沒有發現羽毛的直接證據,但它們在其他地方的普遍存在使得它們有可能長有羽毛。
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