ABSTRACT Despite over a century of prospecting and field research, fossil vertebrates are exceedingly rare in Paleogene and Neogene rocks in northern Canada's Yukon Territory. Here, we describe the first records of probable Neogene vertebrate fossils from the territory, including tooth fragments of a rhinocerotid, a partial calcaneum of an artiodactyl, shell fragments of the pond turtle Chrysemys s.l. and tortoise Hesperotestudo, and a fragment of a palatine of Esox (pike). Although the tooth fragments cannot be identified solely by traditional paleontological means, we use tooth enamel microstructure, and primarily the presence of vertical Hunter-Schreger bands, to refer them to the Rhinocerotidae. As the only known record of the Rhinocerotidae in North America's western Arctic, the tooth fragments from the Wolf Creek site support the hypothesis that the clade dispersed between Asia and North America across Beringia. The fossils are consistent with a Miocene age for the Wolf Creek site that is inferred from radiometric dates of the Miles Canyon basalt flows in the vicinity of the fossil locality. Further, the tortoise and pond turtle fossils indicate a mild climate in the Yukon at the time, consistent with the vegetation reconstructions of others that indicate a warmer, wetter world in the Miocene than today.

中文翻译：

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来自加拿大育空地区的第一批哺乳动物、海龟和鱼类的第三纪化石

摘要 尽管进行了一个多世纪的勘探和实地研究，但在加拿大北部育空地区的古近系和新近系岩石中，脊椎动物化石极为罕见。在这里，我们描述了该地区可能的新近纪脊椎动物化石的第一批记录，包括犀牛的牙齿碎片、偶蹄动物的部分跟骨、池塘龟 Chrysemys sl 和陆龟 Hesperotestudo 的壳碎片，以及 Esox 的颚骨碎片（派克）。尽管仅通过传统的古生物学方法无法识别牙齿碎片，但我们使用牙釉质微观结构，主要是垂直的 Hunter-Schreger 带的存在，将它们称为犀牛科。作为北美西部北极地区唯一已知的犀牛科记录，来自 Wolf Creek 遗址的牙齿碎片支持了这一假设，即该进化枝分散在亚洲和北美之间的白令海峡。这些化石与沃尔夫溪遗址的中新世年龄一致，该年代是从化石地点附近的迈尔斯峡谷玄武岩流的辐射测量日期推断出来的。此外，陆龟和池龟化石表明育空地区当时气候温和，与其他植被重建一致，表明中新世的世界比今天更温暖、更潮湿。