The origin and early radiation of dinosaurs
The origin and early radiation of dinosaurs
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DOI：
10.1016/j.earscirev.2010.04.001
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发表时间：
2010-07-01
影响因子：
12.1
通讯作者：
Norell, Mark A.
中科院分区：
文献类型：
--
作者：
Brusatte, Stephen L.;Nesbitt, Sterling J.;Norell, Mark A.
恐龙在中生代取得了巨大的成功，鸟类这一亚类仍然是现代生态系统的重要组成部分。尽管白垩纪末非鸟类恐龙的灭绝一直是激烈争论的话题，但人们对三叠纪晚期和侏罗纪早期恐龙的起源和早期进化相对较少的关注，这是地球历史上最重要的进化辐射之一。在过去的 25 年里，由于新化石的大量发现、对长期被忽视的标本的重新解释以及综合解剖和地质数据的定量宏观进化分析，我们对这一关键事件的理解发生了巨大的变化。在这里，我们概述了恐龙历史的前 5000 万年，重点关注恐龙从三叠纪晚期几乎边缘的小型爬行动物群体到侏罗纪和白垩纪卓越的陆生脊椎动物的崛起的大规模模式。我们为早期恐龙历史提供了生物学和地质背景。恐龙深深地嵌套在祖龙类爬行动物中，仅通过少数字符进行诊断，并细分为许多主要谱系。第一个明确的恐龙是在南美洲的卡尼期晚期发现的，但它们的姊妹群在三叠纪中期的存在意味着恐龙的起源可能要早得多。三种主要的恐龙谱系：兽脚亚目、蜥脚类和鸟臀目，都是在三叠纪时期发现的，当时大陆连接成超大陆盘古大陆，全球气候炎热干旱。尽管许多研究人员长期以来一直认为恐龙在三叠纪期间击败了其他爬行动物，但我们认为恐龙的崛起更多的是偶然性和机会主义的问题。在大多数晚三叠世生态系统中，恐龙的光芒都被鳄鱼系祖龙所掩盖，并且没有表现出战胜对手的迹象。相反，恐龙的崛起是一个两个阶段的过程，只有在大多数鳄系爬行动物和其他类群灭绝之后，恐龙的分类多样性、形态差异和动物区系绝对丰富度才得以扩展。 (c) 2010 Elsevier B.V. 保留所有权利。
Dinosaurs were remarkably successful during the Mesozoic and one subgroup, birds, remain an important component of modern ecosystems. Although the extinction of non-avian dinosaurs at the end of the Cretaceous has been the subject of intense debate, comparatively little attention has been given to the origin and early evolution of dinosaurs during the Late Triassic and Early Jurassic, one of the most important evolutionary radiations in earth history. Our understanding of this keystone event has dramatically changed over the past 25 years, thanks to an influx of new fossil discoveries, reinterpretations of long-ignored specimens, and quantitative macroevolutionary analyses that synthesize anatomical and geological data. Here we provide an overview of the first 50 million years of dinosaur history, with a focus on the large-scale patterns that characterize the ascent of dinosaurs from a small, almost marginal group of reptiles in the Late Triassic to the preeminent terrestrial vertebrates of the Jurassic and Cretaceous. We provide both a biological and geological background for early dinosaur history. Dinosaurs are deeply nested among the archosaurian reptiles, diagnosed by only a small number of characters, and are subdivided into a number of major lineages. The first unequivocal dinosaurs are known from the late Carnian of South America, but the presence of their sister group in the Middle Triassic implies that dinosaurs possibly originated much earlier. The three major dinosaur lineages, theropods, sauropodomorphs, and ornithischians, are all known from the Triassic, when continents were joined into the supercontinent Pangaea and global climates were hot and arid. Although many researchers have long suggested that dinosaurs outcompeted other reptile groups during the Triassic, we argue that the ascent of dinosaurs was more of a matter of contingency and opportunism. Dinosaurs were overshadowed in most Late Triassic ecosystems by crocodile-line archosaurs and showed no signs of outcompeting their rivals. Instead, the rise of dinosaurs was a two-stage process, as dinosaurs expanded in taxonomic diversity, morphological disparity, and absolute faunal abundance only after the extinction of most crocodile-line reptiles and other groups. (c) 2010 Elsevier B.V. All rights reserved.