封面说明：云南昭通早泥盆世布拉格期无颌类盔甲鱼生态复原图。昭通布拉格期无颌类盔甲鱼物种多样性非常丰富。剑裂甲鱼(Rhegmaspis xiphoidea gen. et sp. nov.)是坡松冲组最新发现的华南鱼目一新属种，其头甲呈鱼雷形，吻突细长，眶孔腹侧位，鳃穴向头甲腹面弯曲，角、内角和腹环丢失。裂甲鱼属是该地区发现的第一个具有流线形体型的盔甲鱼类，指示该地区一些盔甲鱼类可能开始了一种营上底栖的生活方式，具有更加主动的取食行为。裂甲鱼的发现表明在早泥盆世布拉格期盔甲鱼类可能通过占据新的生态位发生了最后一次辐射演化。图中裂甲鱼(前，后右)、昭通鱼(后中)、三歧鱼(后左)畅游在早期维管植物掌裂蕨之间。详见本期盖志琨等人文。(绘图：杨定华)
Cover image: Ecological reconstruction of galeaspids (Agnatha) in Zhaotong, Yunnan Province during the Pragian, Early Devonian. Galeaspids exhibit a high diversity in Zhaotong during the Pragian. Rhegmaspis xiphoidea gen. et sp. nov. is a new form of the Huananaspiformes (Galeaspida) from the Posongchong Formation. The new taxon has a torpedo-shaped head-shield, a long rostral process, ventrolaterally set orbits, and ventrally curved branchial fossae, but no corners, inner corners, and ventral rim of head-shield. As the first streamlined jawless fish in this district, Rhegmaspis displays an adaptation for a suprabenthic lifestyle with more active feeding behavior among galeaspids. The discovery of Rhegmaspis indicates that galeaspids probably experienced the last adaptive radiation in the Pragian of the Early Devonian by occupying an unexploited ecological niche. In the picture, Rhegmaspis (front, back-right), Zhaotongaspis (back-middle) and Sanqiaspis (back-left) were swimming in the coastal water in association with the early vascular plant Catenalis. See details in the paper of Gai et al. (Illustrated by YANG Ding-Hua)
