Collaborative Research: A New Paleogene Fauna from the Chilean Andes: A Critical Interval in South American Mammalian History

加州大学圣巴巴拉分校的安德烈·怀斯和纽约美国自然历史博物馆的马克·诺雷尔将进行合作研究。几乎整个新生代都与其他大陆隔绝，在南美洲形成了一种非常独特和特有的陆地哺乳动物动物群，一个多世纪以来一直吸引着进化生物学家和古生物学家的兴趣。来自智利中部安第斯山脉的一种非同寻常的新动物群，属于南美洲第三纪记录中最鲜为人知的跨度，大约在Mustersan(中始新世)、Deseadan(？晚渐新世)之前的1500万年后。由于这一跨度恰逢一个主要的动物群过渡，这对于理解南美洲主要土著化石哺乳动物群体之间的系统发育关系的几个长期存在的问题至关重要。因此，新的动物群标志着第一个被很好地代表的动物群，澄清了从大陆到始新世-渐新世的过渡。除了具有重要的古生物学意义外，新的动物群还对中安第斯山脉非常广泛的地层学和构造史的解释具有重要意义。这项研究有三个重点。第一个问题是继续进行强有力的野外采集和侦察计划。第二个问题是对这种多样性的、保存完好的、出人意料的化石组合的描述，以及将其成分置于严格的系统发育框架中。第三个问题是将这一发现置于高度整合的地质年代学背景中。为此，将采用生物年代学、磁性地层学和放射性同位素方法。

Collaborative research will be conducted between Andre Wyss (University of California, Santa Barbara) and Mark Norell (American Museum of Natural History, NY). Isolated from other continents for nearly all of the Cenozoic, there developed in South America a highly peculiar and endemic land mammal fauna that has captured the interest of evolutionary biologists and paleontologists for more than a century. An extraordinary new fauna from the Andes of central Chile falls within what previously represented the most poorly known span of the South American Tertiary record, an approximately 15 million year post-Mustersan (middle Eocene), pre-Deseadan (?late Oligocene) interval. As this span coincides with a major faunal transition, it is crucial to the understanding of several long-standing problems of phylogenetic relationship among the major groups of indigenous South American fossil mammals. The new fauna thus marks the first well represented fauna clarifying the Eocene-Oligocene transition from the continent. In addition to being of major paleobiologic importance, the new fauna bears significantly on interpretation of the stratigraphy and tectonic history in a very broad segment of the central Andes. This study has three points of focus. The first involves a continued vigorous field collection and reconnaissance program. The second concerns description of this diverse, well preserved, and highly unexpected fossil assemblage, and placement of its constituents into a rigorous phylogenetic framework. The third consists of the discovery's placement into a highly integrated geochronologic context. To that end, biochronologic, magnetostratigraphic, and radioisotopic methods will be employed.