Soligo Christophe
Department of Anthropology, University College London, London, UK.
Folia Primatol (Basel). 2007;78(5-6):297-313. doi: 10.1159/000105146. Epub 2007 Sep 7.
The Palaeocene-Eocene transition is characterized by a significant turnover of mammalian taxa in the fossil record of the northern continents, and primates are among the groups that make their first appearance at this time. One of the many questions that remain to be answered with regard to the earliest evolution of primates is the reason for their sudden and virtually simultaneous appearance in the fossil records of Asia, Europe and North America. The most obvious environmental correlate of the Palaeocene-Eocene transition is a sharp but relatively short-lived warming event leading up to the Palaeocene-Eocene thermal maximum (PETM) and evidenced in the stratigraphic record by a negative delta(13)C excursion. It remains unclear, however, whether or how this warming event may have influenced Palaeocene-Eocene faunal turnovers. This paper explores the hypothesis that environmental changes associated with the PETM facilitated an invasion of Western Europe by primates by comparing the ecological structure of local mammalian fauna immediately before and following the Palaeocene-Eocene transition. The results suggest that changes to the ecological profile of local mammalian fauna were relatively small and did not favour an invasion by primates, although a major uncertainty remains with respect to the availability of arboreal niches. At present it seems more likely that the invasion of western Europe by primates was due to the breakdown of one or more dispersal barriers close to the end of the Palaeocene.
古新世-始新世过渡时期的特征是北半球各大洲化石记录中哺乳动物类群的显著更替，灵长类动物就是在这个时期首次出现的类群之一。关于灵长类动物最早进化仍有待解答的众多问题之一，是它们为何突然且几乎同时出现在亚洲、欧洲和北美的化石记录中。古新世-始新世过渡时期最明显的环境关联因素是在古新世-始新世极热事件（PETM）之前出现的一次急剧但持续时间相对较短的变暖事件，在地层记录中表现为δ(13)C负偏移。然而，目前尚不清楚这次变暖事件是否以及如何影响了古新世-始新世的动物群更替。本文通过比较古新世-始新世过渡前后当地哺乳动物群的生态结构，探讨了与PETM相关的环境变化促进灵长类动物入侵西欧的假说。结果表明，当地哺乳动物群生态特征的变化相对较小，并不利于灵长类动物的入侵，尽管关于树栖生态位的可利用性仍存在一个主要的不确定性。目前看来，灵长类动物入侵西欧更有可能是由于接近古新世末期一个或多个扩散障碍的瓦解。
