Data from: The plumage and colouration of an enantiornithine bird from the Early Cretaceous of China

Brilliant colour displays and diverse feather morphologies that are often sexual ornaments are common throughout much of extant Avialae. Here we describe a new basal enantiornithine bird specimen recovered from the Early Cretaceous Jiufotang Formation of Liaoning Province in northeastern China. We present new information on the plumage of Bohaiornithidae as well as the first detailed colour reconstruction of an enantiornithine bird. The new specimen retains subadult skeletal characteristics, including periosteal pitting of the long bone epiphyses and unfused elements, while also preserving plumage evidence consistent with sexual maturity at the time of death. Exceptionally-preserved feathers cover the body, including elongate crown feathers, body contour feathers, asymmetrically-veined wing primaries, an alula and two elongate rachis-dominated rectrices that may have been sexual ornaments. The crown, neck, and body contour feathers retain elongate melanosome morphologies associated with weakly iridescent colouration in extant feathers. We provide additional evidence of preserved melanin using Raman spectroscopy; a rapid, non-destructive chemical technique. The new specimen provides data on skeletal ontogeny in the Bohaiornithidae as well as evidence for intraspecific communication functions of plumage.在现存鸟翼类（Avialae）的多数类群中，艳丽的色彩展示与常作为性炫耀装饰的多样羽毛形态均较为常见。本文记述了一件产自中国东北部辽宁省早白垩世九佛堂组的新基干反鸟类（Enantiornithes）标本。本次研究不仅提供了渤海鸟科（Bohaiornithidae）羽毛的全新资料，同时实现了反鸟类的首次详细色彩复原。该新标本保留有亚成体的骨骼特征，包括长骨骨骺的骨膜凹陷（periosteal pitting）以及未愈合的骨骼结构，同时其保存的羽毛痕迹表明该个体死亡时已达性成熟。其全身覆盖有保存状态极佳的羽毛，包括修长的头顶羽毛、体廓羽、具不对称羽脉的初级飞羽、小翼羽（alula），以及两枚修长的以羽轴为主体的尾羽，此类尾羽或可作为性炫耀装饰结构。头顶、颈部以及体廓羽中保留有修长的黑素体（melanosome）形态，该形态与现生羽毛中的弱虹彩色彩相关。本次研究还借助拉曼光谱法（Raman spectroscopy）——一种快速且无损的化学分析技术——为黑色素的保存情况提供了额外佐证。本件新标本不仅为渤海鸟科的骨骼个体发育研究提供了数据支撑，同时也为羽毛的种内交流功能提供了实证依据。