Carrillo Juan D, Forasiepi Analía, Jaramillo Carlos, Sánchez-Villagra Marcelo R
Paläontologisches Institut und Museum, University of Zurich Zurich, Switzerland ; Smithsonian Tropical Research Institute Panama City, Panama.
Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA), CCT-CONICET Mendoza Mendoza, Argentina.
Front Genet. 2015 Jan 5;5:451. doi: 10.3389/fgene.2014.00451. eCollection 2014.
The vast mammal diversity of the Neotropics is the result of a long evolutionary history. During most of the Cenozoic, South America was an island continent with an endemic mammalian fauna. This isolation ceased during the late Neogene after the formation of the Isthmus of Panama, resulting in an event known as the Great American Biotic Interchange (GABI). In this study, we investigate biogeographic patterns in South America, just before or when the first immigrants are recorded and we review the temporal and geographical distribution of fossil mammals during the GABI. We performed a dissimilarity analysis which grouped the faunal assemblages according to their age and their geographic distribution. Our data support the differentiation between tropical and temperate assemblages in South America during the middle and late Miocene. The GABI begins during the late Miocene (~10-7 Ma) and the putative oldest migrations are recorded in the temperate region, where the number of GABI participants rapidly increases after ~5 Ma and this trend continues during the Pleistocene. A sampling bias toward higher latitudes and younger records challenges the study of the temporal and geographic patterns of the GABI.
新热带界丰富的哺乳动物多样性是长期进化历史的结果。在新生代的大部分时间里，南美洲是一个拥有特有哺乳动物群的岛屿大陆。在巴拿马地峡形成后的新近纪晚期，这种隔离状态结束，导致了一场被称为“大美洲生物交流”（GABI）的事件。在本研究中，我们调查了南美洲在首次记录到移民之前或之时的生物地理模式，并回顾了GABI期间化石哺乳动物的时间和地理分布。我们进行了差异分析，根据动物群组合的年龄和地理分布对其进行分组。我们的数据支持了中新世中期和晚期南美洲热带和温带组合之间的分化。GABI始于中新世晚期（约1000 - 700万年前），最早的假定迁徙记录出现在温带地区，在约500万年后，GABI参与者的数量在该地区迅速增加，并且这种趋势在更新世持续。对高纬度地区和较新记录的采样偏差给研究GABI的时间和地理模式带来了挑战。
