A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution

Matthew D Shawkey,Xing Xu,Chad M Eliason,Cuilin Zhao,Julia A Clarke,Jinkai Jiang,Dongyu Hu,Rui Qiu,Liliana D’Alba,Quanguo Li

doi:10.1038/s41467-017-02515-y

Abstract

The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and particularly of bird origins, but, with the exception of the bizarre scansoriopterygids, they have shown similar skeletal and integumentary morphologies. Here we report a distinctive new Yanliao theropod species bearing prominent lacrimal crests, bony ornaments previously known from more basal theropods. It shows longer arm and leg feathers than Anchiornis and tail feathers with asymmetrical vanes forming a tail surface area even larger than that in Archaeopteryx. Nanostructures, interpreted as melanosomes, are morphologically similar to organized, platelet-shaped organelles that produce bright iridescent colours in extant birds. The new species indicates the presence of bony ornaments, feather colour and flight-related features consistent with proposed rapid character evolution and significant diversity in signalling and locomotor strategies near bird origins.

Highlights

The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and of bird origins, but, with the exception of the bizarre scansoriopterygids, they have shown similar skeletal and integumentary morphologies
The newly discovered Yanliao specimen described here is another exception to the general pattern. This new theropod shows an array of bony features, as well as plumage characteristics and putative melanosome morphologies not previously seen in other Paraves, and further informs the pattern of character acquisition close to the origin of avian flight
PMoL-B00175 (Paleontological Museum of Liaoning), a nearly complete skeleton with associated plumage preserved on a slab and counter slab from Gangou, Qinglong, northern Hebei Province, Tiaojishan Formation, early Late Jurassic, ~161 Myr[9] (Supplementary Figs. 1–5; Supplementary Notes 1 and 2)

Summary

Introduction

The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and of bird origins, but, with the exception of the bizarre scansoriopterygids, they have shown similar skeletal and integumentary morphologies. We report a distinctive new Yanliao theropod species bearing prominent lacrimal crests, bony ornaments previously known from more basal theropods. It shows longer arm and leg feathers than Anchiornis and tail feathers with asymmetrical vanes forming a tail surface area even larger than that in Archaeopteryx. The newly discovered Yanliao specimen described here is another exception to the general pattern This new theropod shows an array of bony features, as well as plumage characteristics and putative melanosome morphologies not previously seen in other Paraves, and further informs the pattern of character acquisition close to the origin of avian flight

Methods

Results

Conclusion