论文部分内容阅读
在过去20年中,对非鸟兽脚类恐龙向鸟类演化过程的重建工作取得了很大进展,但是关于这一演化假说仍然存在一些反对的观点,其中一个反对证据来自兽脚类恐龙化石的地层分布记录.从兽脚类恐龙化石的地层分布上看,目前已知最古老的鸟类发现于晚侏罗世,而在侏罗系地层中却很少发现应当是它们祖先类型的虚骨龙类化石,这暗示存在着一个“时间悖论”——后裔出现在祖先之前.本文回顾有关这一研究问题的最新进展.近10年来的一系列发现表明,虚骨龙类主要类群在侏罗纪中晚期已经出现.这些发现大大提高了化石地层分布和兽脚类恐龙系统发育关系的一致性,并且有力反驳了所谓的“时间悖论”.更为重要的是,这些发现为鸟类起源研究的核心问题——兽脚类恐龙的系统发育研究提供了重要的信息,支持了暴龙超科和阿尔瓦兹龙超科处于虚骨龙类相对基干的位置,甚至暗示一个新的关于副鸟类的系统发育假说:始祖鸟、驰龙科和伤齿龙科构成一个单系类群,而攀龙类、其他鸟类以及窃蛋龙类形成另一个演化分支.特征演化分析表明,副鸟类的基干类群可能在晚侏罗世之前已经演化出与树栖以及飞行相关的特征.未来更多侏罗纪虚骨龙类化石的发现将有助于一个更加精确的鸟类起源和演化模式的建立.
In the past two decades, great progress has been made in the reconstruction of non-ornithological dinosaurs, but there are still some objections about this evolutionary hypothesis. One of the objections is evidence from the origins of theropod dinosaurs Of the stratigraphic records from the stratum genus dinosaur fossil distribution point of view, the oldest known bird found in the Late Jurassic, but rarely found in the Jurassic strata should be their ancestral type of virtual Bone dragon and fossil, suggesting the existence of a “paradox of time” - descendants before the ancestors.This paper reviews the latest research progress on this issue.A series of findings over the past 10 years indicate that the copepod The taxon has emerged in the middle and late Jurassic, and these findings have greatly increased the consistency of fossil stratigraphic distribution and the phylogenetic relationships of theropods, and strongly refuted the so-called “time paradox.” More importantly, these findings It provides important information for the study of phylogeny of theropod dinosaurs, which is the core issue of bird’s origin research. It supports that the tyrannosaurids superfamily and the Alwarzian superfamily are located in the relative base , Even suggesting a new phylogenetic hypothesis concerning the parakeetus: Archeopteryx, Chironosaurus and Ranunculaceae constitute a monophyletic group, while the Panacea, other birds, and Stegosaurus form another evolutionary branch. Evolutionary analysis of the characteristics indicates that the ephemeral trunk group may have evolved archeological and flight-related features before Late Jurassic. The discovery of more Jurassic Phallus fossils in the future will contribute to a more accurate The establishment of the origin and evolution pattern of birds.