Martin Robert D, Soligo Christophe, Tavaré Simon
Anthropology Department, Field Museum of Natural History, Chicago, Ill., USA.
Folia Primatol (Basel). 2007;78(5-6):277-96. doi: 10.1159/000105145. Epub 2007 Sep 7.
It has long been accepted that the adaptive radiation of modern placental mammals, like that of modern birds, did not begin until after the Cretaceous/Tertiary (K/T) boundary 65 million years (Ma) ago, following the extinction of the dinosaurs. The first undoubted fossil relatives of modern primates appear in the record 55 Ma ago. However, in agreement with evidence from molecular phylogenies calibrated with dates from denser parts of the fossil record, a statistical analysis of the primate record allowing for major gaps now indicates a Cretaceous origin of euprimates 80-90 Ma ago. If this interpretation is correct, primates overlapped with dinosaurs by some 20 Ma prior to the K/T boundary, and the initial radiation of primates was probably truncated as part of the major extinction event that occurred at the end of the Cretaceous. Following a review of evidence for an early origin of primates, implications of this are discussed with respect to the likely ancestral condition for primates, including a southern continental area of origin and moderately large body size. The known early Tertiary primates are re-interpreted as northern continental offshoots of a 'second wave' of primate evolution.
长期以来，人们一直认为，现代胎盘哺乳动物的适应性辐射，就像现代鸟类一样，直到6500万年前白垩纪/第三纪（K/T）边界之后恐龙灭绝才开始。现代灵长类动物最早的确切化石亲属出现在5500万年前的记录中。然而，与根据化石记录更密集部分的日期校准的分子系统发育证据一致，现在对灵长类记录进行的一项考虑到主要空白的统计分析表明，真灵长类动物起源于8000万至9000万年前的白垩纪。如果这种解释是正确的，那么灵长类动物在K/T边界之前约2000万年就与恐龙重叠了，并且灵长类动物的最初辐射可能作为白垩纪末期发生的重大灭绝事件的一部分而被截断。在回顾了灵长类动物早期起源的证据之后，讨论了这对于灵长类动物可能的祖先状况的影响，包括起源于南方大陆地区和中等体型。已知的早第三纪灵长类动物被重新解释为灵长类动物进化“第二波”的北方大陆分支。
