The Willwood Formation of the southern Bighorn Basin, Wyoming is a fluvial rock sequence that spans approximately 3 million years of early Eocene time. It has yielded one the largest collections of fossil mammals in the world including thousands of dentitions of extinct lemur‐like primates known as notharctines. In the southern Bighorn Basin, specimens of these primates have been collected on numerous paleontological expeditions and the stratigraphic levels yielding the dentitions have been carefully recorded. Notharctine dentitions represent a rare opportunity to study morphological variation in a single anatomical system through time among closely related individuals.

中文翻译：

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来自怀俄明州早期始新世威尔伍德组的化石灵长类动物（巨齿类，齿形科，齿形科）的致密样本：牙齿面积和形状随时间逐渐变化的记录

怀俄明州比格霍恩盆地南部的威尔伍德组是一条河流相岩石序列，横跨始新世早期约三百万年。它已产生了世界上最大的化石哺乳动物集合之一，其中包括成千上万种已灭绝的狐猴状灵长类动物齿齿，它们被称为notharctines。在比格霍恩盆地南部，已在许多古生物学考察中收集了这些灵长类动物的标本，并仔细记录了产生牙列的地层水平。Notharctine齿列代表了密切相关个体之间通过时间研究单个解剖系统中形态变化的难得机会。