Quaternary glaciation and the Great American Biotic Interchange
Quaternary glaciation and the Great American Biotic Interchange
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DOI：
10.1130/g37624.1
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发表时间：
2016-05-01
期刊：
影响因子：
5.8
通讯作者：
Camila Vallejo-Pareja, Maria
中科院分区：
文献类型：
--
作者：
Bacon, Christine D.;Molnar, Peter;Camila Vallejo-Pareja, Maria
最近的地质研究表明，巴拿马地峡出现了大约1000万年。比之前设想的要早。虽然今天在巴拿马没有，中美洲稀树草原环境可能与北方半球冰川的开始有关。众所周知，2.5Ma以来穿越地峡的哺乳动物大多生活在稀树草原。气候引起的巴拿马植被变化能否解释哺乳动物的延迟迁移，而不是陆地连通性？我们通过对化石数据和分子生物学的分析，探讨了跨大陆哺乳动物迁徙与气候变化之间的一致性。化石证据表明，绝大多数哺乳动物在公元前1000年后在南美洲和北美洲之间杂交。三马。相比之下，过时的哺乳动物生殖表明，迁移事件开始得更早，约。4-3马，但允许偏向更大的分子年龄比地质测年和不确定性，在前者，我们认为这个年龄范围不显着早于3马。我们的结论是，大草原样的环境中开发的巨大的劳伦泰德冰盖在第一次第四纪冰川触发了启动的大美洲生物交流哺乳动物。
Recent geological studies demonstrate that the Isthmus of Panama emerged some 10 m.y. earlier than previously assumed. Although absent today in Panama, Central American savanna environments likely developed in connection with the onset of Northern Hemisphere glaciations. As is widely recognized, most of the mammals crossing the isthmus since 2.5 Ma lived in savannas. Could climate-induced vegetational changes across Panama explain the delayed migration of mammals, rather than terrestrial connectivity? We investigate the congruence between cross-continental mammal migration and climate change through analysis of fossil data and molecular phylogenies. Evidence from fossil findings shows that the vast majority of mammals crossed between South and North America after ca. 3 Ma. By contrast, dated mammal phylogenies suggest that migration events started somewhat earlier, ca. 4-3 Ma, but allowing for biases toward greater ages of molecular than geologic dating and uncertainties in the former, we consider this age range not to be significantly earlier than 3 Ma. We conclude that savanna-like environments developed in response to the vast Laurentide ice sheet at the first Quaternary glaciation triggered the initiation of the Great American Biotic Interchange in mammals.