Feathered Fossils

THE next time people see an adventure sci-fi movie like Hollywood＇s Jurassic Park, dinosaurs in the movie may look very different, especially the Tyrannosaurus rex. They could be feathered,

Ornamental feathers in Cretaceous Burmese amber:resolving the enigma of rachis-dominated feather structure

Over the last 20 years, compression fossils of feathers surrounding dinosaurs have greatly expanded our understanding of the origin and evolution of feathers. One of the most peculiar feather morphotypes discovered to date are rachis dominated feathers(RDFs), which have also been referred to as proximally ribbon-like pennaceous feathers(PRPFs). These elongate feathers are only found in the tail plumage, typically occurring in pairs with both streamer(not proximally ribbon-like) and racket-plume morphologies recognized. Here we describe a large sample set of isolated and paired RDFs from Upper Cretaceous Burmese amber(～ 99 Ma). Amber preserves the finest details of these fragile structures in three dimensions, demonstrating that RDFs form a distinct feather morphotype with a ventrally open rachis, and with significant variability in pigmentation, microstructure, and symmetry.

1.3亿年前早期鸟类化石揭示尾骨与扇状尾羽独立演化

在恐龙向鸟类演化的过程中,尾骨变化最为显著,由于缺少过渡环节的化石,这一演化过程并不清楚。现代鸟类的尾骨缩短并愈合成犁状尾综骨,其上附有扇状尾羽而构成飞行器官的重要组成部分。学术界普遍认为犁状尾综骨和扇状尾羽是同步演化的。中国科学院古脊椎动物与古人类研究所王敏等报道了在河北白垩纪地层中发现的1.3亿年前的反鸟类化石,显示其具有与现代鸟类相似的犁状尾综骨,但却并不具有扇状尾羽。本研究组综合形态学、骨组织学和扫描电镜等方法,提出"犁状尾综骨与扇状尾羽在早期鸟类中相互独立"的假设,挑战了此前长期占主流的学术观点。相较于犁状尾综骨在今鸟型类的广泛发育,这一结构在部分反鸟类中的出现则是平行演化的结果,结合越来越多的其他化石证据,表明在鸟类演化早期,平行演化是一个非常普遍的现象,这也为依据骨骼形态讨论中生代鸟类的系统发育关系提出了挑战。

简述羽毛化石颜色研究

化石羽毛颜色特征对探讨带毛恐龙和早期鸟类的起源及其生活习性有着重要的意义。本文论述了现生羽毛成色机制和化石羽毛颜色复原的相关研究进展,认为化石羽毛结构色的恢复是羽毛化石研究工作的一大难点。结构色在现生羽毛中具有重要地位,并且与羽毛结构演化有着密切的关系,因此在无法确定化石羽毛精细结构的情况下,对处于演化早期阶段的羽毛化石,仅通过化学色素来复原其颜色具有较高的合理性。