Cover image: reconstruction of a juvenile enantiornithine (Aves: Ornithothoraces) with immature feathers, in the process of forming a new plumage. In modern birds, juveniles molt their feathers at least once going through one or more pre-basic plumages before reaching the adult (basic) plumage. New research documents this process for the first time in four juvenile enantiornithines. Enantiornithines hatch with fully functional flight feathers on their wings that allow them to fly immediately, but their body feathers are primitive and tail feathers appear later in ontogeny. The four described specimens preserve immature feathers forming on the body and tail that are interpreted as the incoming basic plumage of the adult. See details in the paper of O’Connor et al. (p.24). (Illustrated by Carlos Vidoso)
 
封面说明：一个尚附着有未成熟羽毛，正在长出新羽的反鸟类幼年个体复原图。现代鸟类的雏鸟至少需要经过一次换羽的过程才能长出成年个体所具有的羽毛。新研究在4个反鸟类幼年个体中首次记录了这一过程。刚刚孵化的反鸟虽然已经长出具有飞行功能的飞羽，但是其体羽和尾羽还远未成熟。这4个反鸟类个体的身体和尾部保存的未成熟羽毛，被解读为即将出现的成年个体羽毛的基本形态。详见邹晶梅等人文(p.24)。(绘图：Carlos Vidoso)