作者：司矗东，盖志琨，赵文金
摘要：主要采用形态学与比较解剖学的方法，对采自云南曲靖地区下泥盆统西山村组中的1件盔甲鱼类标本进行了详细的形态学研究，建立了多鳃鱼类四营鱼属1新种：宽棘四营鱼(Siyingia perlatuspinosa sp. nov.), 并据此修订了四营鱼属的特征。在此基础上，应用分支系统学对多鳃鱼类属一级的系统发育关系进行了重新分析与探讨，确定了四营鱼在多鳃鱼类中的系统发育位置。系统发育分析结果显示，四营鱼(Siyingia)与多鳃鱼(Polybranchiaspis)亲缘关系最近，二者形成了一个单系类群，与宽甲鱼(Laxaspis)+坝鱼(Damaspis)组成的单系类群互为姊妹群。宽棘四营鱼的发现不仅拓宽了四营鱼在华南的时空分布范围，而且丰富了多鳃鱼类的多样性，并为多鳃鱼类的深入研究提供了可靠的化石新证据。
关键词：云南曲靖，早泥盆世，西山村组，多鳃鱼类，四营鱼
Anew species ofSiyingia from the Lower Devonian Xishancun Formation of Qujing, Yunnan
SI Chu-Dong, GAI Zhi-Kun, ZHAO Wen-Jin
Abstract This paper describes a new species of the Polybranchiaspiformes (Agnatha: Galeaspida), Siyingia perlatuspinosa sp. nov., from the Early Devonian Xishancun Formation in Qujing, East Yunnan, southwestern China. The diagnosis of the genus Siyingia is emended based on data from the holotype of the new species. A phylogenetic analysis, using an expanded version of the data matrix of Zhu and Gai defined in 2006, suggests that Siyingia and Polybranchiaspis form the monophyletic sister group of a clade containing Laxaspis and Damaspis. This discovery increases the known Early Devonian diversity of polybranchiaspiforms, and helps to clarify the pattern of interrelationships within the Polybranchiaspiformes.
Key words Qujing, Yunnan, China; Early Devonian; Xishancun Formation; Polybranchiaspiformes, Siyingia
