Seiffert Erik R, Perry Jonathan M G, Simons Elwyn L, Boyer Doug M
Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York 11794-8081, USA.
Nature. 2009 Oct 22;461(7267):1118-21. doi: 10.1038/nature08429.
Adapiform or 'adapoid' primates first appear in the fossil record in the earliest Eocene epoch ( approximately 55 million years (Myr) ago), and were common components of Palaeogene primate communities in Europe, Asia and North America. Adapiforms are commonly referred to as the 'lemur-like' primates of the Eocene epoch, and recent phylogenetic analyses have placed adapiforms as stem members of Strepsirrhini, a primate suborder whose crown clade includes lemurs, lorises and galagos. An alternative view is that adapiforms are stem anthropoids. This debate has recently been rekindled by the description of a largely complete skeleton of the adapiform Darwinius, from the middle Eocene of Europe, which has been widely publicised as an important 'link' in the early evolution of Anthropoidea. Here we describe the complete dentition and jaw of a large-bodied adapiform (Afradapis gen. nov.) from the earliest late Eocene of Egypt ( approximately 37 Myr ago) that exhibits a striking series of derived dental and gnathic features that also occur in younger anthropoid primates-notably the earliest catarrhine ancestors of Old World monkeys and apes. Phylogenetic analysis of 360 morphological features scored across 117 living and extinct primates (including all candidate stem anthropoids) does not place adapiforms as haplorhines (that is, members of a Tarsius-Anthropoidea clade) or as stem anthropoids, but rather as sister taxa of crown Strepsirrhini; Afradapis and Darwinius are placed in a geographically widespread clade of caenopithecine adapiforms that left no known descendants. The specialized morphological features that these adapiforms share with anthropoids are therefore most parsimoniously interpreted as evolutionary convergences. As the largest non-anthropoid primate ever documented in Afro-Arabia, Afradapis nevertheless provides surprising new evidence for prosimian diversity in the Eocene of Africa, and raises the possibility that ecological competition between adapiforms and higher primates might have played an important role during the early evolution of stem and crown Anthropoidea in Afro-Arabia.
兔猴型或“类兔猴”灵长类动物最早出现在始新世早期的化石记录中（约5500万年前），是欧洲、亚洲和北美洲古近纪灵长类群落的常见组成部分。兔猴型动物通常被称为始新世的“狐猴样”灵长类动物，最近的系统发育分析将兔猴型动物置于原猴亚目（Strepsirrhini）的基干成员位置，该灵长类亚目的冠群包括狐猴、懒猴和婴猴。另一种观点认为兔猴型动物是类人猿的基干。最近，对来自欧洲始新世中期的兔猴型动物达尔文狐猴（Darwinius）一具基本完整骨架的描述重新引发了这场争论，该骨架被广泛宣传为灵长目早期进化中的一个重要“环节”。在此，我们描述了一种来自埃及始新世晚期最早期（约3700万年前）的大型兔猴型动物（新属非洲狐猴[Afradapis gen. nov.]）的完整齿列和颌骨，它展现出一系列显著的衍生牙齿和颌骨特征，这些特征也出现在更晚的类人猿灵长类动物中——尤其是旧世界猴和猿最早的狭鼻猴祖先。对117种现存和已灭绝灵长类动物（包括所有候选类人猿基干物种）的360个形态特征进行系统发育分析，结果并未将兔猴型动物置于简鼻亚目（即跗猴 - 类人猿分支的成员）或类人猿基干位置，而是将其置于原猴亚目冠群的姐妹分类单元位置；非洲狐猴和达尔文狐猴被置于一个在地理上广泛分布的新猿猴类兔猴型动物分支中，该分支没有已知后代。因此，这些兔猴型动物与类人猿共有的特化形态特征最简约的解释是进化趋同。作为在非洲 - 阿拉伯地区有记录以来最大的非类人猿灵长类动物，非洲狐猴仍然为非洲始新世原猴类的多样性提供了惊人的新证据，并增加了一种可能性，即兔猴型动物与高等灵长类动物之间的生态竞争可能在非洲 - 阿拉伯地区类人猿基干和冠群的早期进化过程中发挥了重要作用。
