Abstract From the northern part of Chukotka Region (Russian Far East) and Nether-Polar Urals, one of the oldest and one of the most northerly occurrences of mosasaur remains in the world are recorded. The appearance of mosasaurs at high latitudes could be explained by the expansion of their habitat and an unusual balance of insolation. Polar day conditions could have been useful for marine predators such as mosasaurs because they could have hunted for prey at any time. During the Cretaceous, almost two months of complete darkness can be reconstructed for the territory of present-day Chukotka, and more than one month of twilight. It is highly unlikely that these large-sized animals with a high metabolic rate were capable of surviving in complete darkness. Seen in this light, mosasaur remains at both high and low latitudes can serve as indirect evidence of seasonal migrations.

中文翻译：

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来自俄罗斯上白垩纪的北极沧龙（有鳞、沧龙科）

摘要 在楚科奇地区北部（俄罗斯远东）和下极乌拉尔地区，记录了世界上最古老和最北端的沧龙遗骸之一。沧龙在高纬度地区的出现可以用它们栖息地的扩张和异常的日照平衡来解释。极昼条件可能对沧龙等海洋捕食者有用，因为它们可以随时捕食猎物。在白垩纪，现在楚科奇领土可以重建近两个月的完全黑暗，以及一个多月的暮光之城。这些具有高代谢率的大型动物极不可能在完全黑暗中生存。从这个角度看，