Paleontological Investigations to Recover Fossil Monkeys from the Middle Cenozoic of South America

摘要南美洲猴子进化的模式没有得到很好的记录，也很少被理解。一些人认为，在巴塔哥尼亚1600万至2000万年前的岩石上发现的新大陆猴子(Platyrrhini)早于现代家族的起源，也就是说，它们是“茎白颈猴”。其他人则认为，它们是现代鸭嘴兽家族的早期代表。这两种不同的解释对如何看待鸭嘴兽的进化辐射有着深远的影响。更多早期鸭嘴兽的化石材料将有助于解决这一争论。一个由美国和阿根廷古生物学家组成的联合小组将在阿根廷巴塔哥尼亚的圣克鲁斯组和相当于1600万年前的岩石中寻找灵长类化石。收集工作将集中在已探明的地点，并将收集工作扩大到其他鲜为人知的地点，据说这些地点从大西洋海岸内陆到南纬50-55度的安第斯前缘都有丰富的化石。对现有材料的分析以及对更完整的灵长类动物标本的回收，将为这些早期类人灵长类动物的系统发育和适应提供难得的洞察。系统发育分析将阐明南美鸭嘴猴的多样化模式，并有助于完善关于现代鸭嘴猴家族起源的假说。为了重建各种灭绝物种的适应概况，来自美国、阿根廷和巴西的一个科学家团队将研究牙齿、头骨和四肢骨骼的各个方面，以重建每个物种适应和生活史的重要细节。野外小组收集的其他动物遗骸将填补早期鸭嘴兽进化的环境背景。由阿根廷科学家领导的第二个研究专家小组将研究非灵长类化石的功能解剖和生态形态。人们已经开展了大量的工作来研究树懒和螳螂。使用这些已建立的方法作为模型，研究小组将把这项工作扩展到包括啮齿动物、非袋鼠和有袋类在内的其他主要哺乳动物群体。

AbstractThe pattern of monkey evolution in South America is poorly documented and little understood. Some argue that New World monkeys (Platyrrhini) known from 16-20 million year old rocks of Patagonia predate the origins of the modern families, that is, they are 'stem platyrrhines'. Others argue that they are early representatives of the modern platyrrhine families. The two alternative interpretations have profound implications for how the evolutionary radiation of platyrrhines is viewed. Further fossil material of early platyrrhines will contribute to resolving this debate. A joint team of US and Argentine paleontologists will search for fossil primates in ~16 million-year-old rocks of the Santa Cruz Formation and its equivalents in Patagonian Argentina. Collecting will concentrate on proven localities and expand collecting efforts to other lesser-known sites said to be richly fossiliferous from the Atlantic coast inland to the Andean front at 50-55 degrees South latitude. Analysis of the existing materials and recovery of even more complete specimens of primates will offer a rare insight about the phylogeny and adaptations of these early anthropoid primates. A phylogenetic analysis will clarify the pattern of diversification of South American platyrrhine monkeys and help to refine hypotheses about the origins of the modern platyrrhines families. To reconstruct adaptive profile of the various extinct species, a team of scientists from the US, Argentina and Brazil will study various aspects of the teeth, skulls and limb bones to reconstruct important details of the each species' adaptation and life history. Collections of other faunal remains by the field group will fill out the environmental context in which early platyrrhines evolved. A second team of research specialists headed by the Argentine scientists will study the functional anatomy and ecomorphology of non-primate fossils. Much work already has been undertaken to study the sloths and armadillos. Using these established approaches as a model, the research group will extend this work to encompass other major mammal groups including rodents, notoungulates, and marsupials.