The phylogeny of early amniotes and the affinities of Parareptilia and Varanopidae
The phylogeny of early amniotes and the affinities of Parareptilia and Varanopidae
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DOI：
10.1038/s41559-019-1047-3
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发表时间：
2020-01-01
影响因子：
16.8
通讯作者：
Benson, Roger B. J.
中科院分区：
文献类型：
--
作者：
Ford, David P.;Benson, Roger B. J.
羊膜动物包括哺乳动物、爬行动物和鸟类，占陆地上现存脊椎动物物种的75%。它们起源于大约3.18亿年前的晚石炭纪早期，它们的早期化石记录对于理解脊椎动物在陆地生态系统中的扩张至关重要。我们提出了一个系统发育的假设，挑战了广泛接受的共识，早期的蝙蝠进化，基于简约分析和贝叶斯推理的一个新的形态数据集。我们发现哺乳动物干谱系的成员减少，不包括varanopids。这意味着哺乳动物干谱系在早中二叠世过渡（2.73亿年前）的进化周转比以前认识到的更突然。我们还发现，Parareptilia是嵌套在Diapsida。这表明，时间开窗，一个关键的结构创新具有重要的功能意义，进化的次数比一般认为的要少，但在其最初的起源后，在早期爬行动物中表现出高度可变的形态。我们的系统发生学还解决了关于中龙科的亲缘关系的争议，中龙科是已知最早的水生类，我们将其恢复为早期的分歧parareptiles。
Amniotes include mammals, reptiles and birds, representing 75% of extant vertebrate species on land. They originated around 318 million years ago in the early Late Carboniferous and their early fossil record is central to understanding the expansion of vertebrates in terrestrial ecosystems. We present a phylogenetic hypothesis that challenges the widely accepted consensus about early amniote evolution, based on parsimony analysis and Bayesian inference of a new morphological dataset. We find a reduced membership of the mammalian stem lineage, which excludes varanopids. This implies that evolutionary turnover of the mammalian stem lineage during the Early-Middle Permian transition (273 million years ago) was more abrupt than has previously been recognized. We also find that Parareptilia are nested within Diapsida. This suggests that temporal fenestration, a key structural innovation with important functional implications, evolved fewer times than generally thought, but showed highly variable morphology among early reptiles after its initial origin. Our phylogeny also addresses controversies over the affinities of mesosaurids, the earliest known aquatic amniotes, which we recover as early diverging parareptiles.A new amniote phylogeny excludes varanopids as stem-line mammals, nests Parareptilia within Diapsida and suggests that temporal fenestration evolved fewer times than previously thought.