三叶虫Fuchouia长期被作为贵州寒武系甲劳组生物地层划分和对比的重要依据,但关于Fuchouia和Parafuchouia的系统分类位置一直存在争议。主要有以下三个观点: Parafuchouia是Fuchouia的亚属、Parafuchouia是Fuchouia的晚出异名以及Parafuchouia可提升为一个单独的属。本文根据在剑河八郎甲劳组采集的Fuchouia [过去被报道为Parafuchouia或Fuchouia (Parafuchouia)]标本和前人报道的Fuchouia、Parafuchouia标本, 基于线性测量的几何形态测量方法, 对Parafuchouia和Fuchouia的头部形态特征进行分析研究, 结果显示Parafuchouia是Fuchouia的晚出异名, 其区别于Fuchouia的特征可作为种间差异的判定依据。这样, 剑河甲劳组可能是目前全球Fuchouia的最低产出层位之一。尽管Fuchouia在中国、朝鲜、印度—喜马拉雅、澳大利亚、哈萨克斯坦等地广泛分布, 但已报道的产出层位多从鼓山阶Ptychagnostus atavus带至古丈阶Lejopyge laevigata带, 延限跨度较大, 很难用Fuchouia这一属级单位来进行生物地层对比。因此贵州寒武系甲劳组目前已建立的Fuchouia生物地层带还需进一步商榷, 需具体到种一级别或另选其他对比分子才能与寒武系华南斜坡相区或华北台地相区进行更好的同期地层对比。

For a long time, Fuchouia has been regarded as a crucial taxon for biostratigraphic division and correlation of Jialao Formation in Jianhe, Guizhou. However, the systematic positions of Fuchouia and Parafuchouia still remain controversial, with the following three main viewpoints: Parafuchouia is a subgenus of Fuchouia; Parafuchouia is a junior synonym of Fuchouia; and Parafuchouia can be elevated to a separate genus. Based on the specimens of Fuchouia collected from Jialao Formation in Jianhe and previously reported as Parafuchouia or Fuchouia (Parafuchouia), and the specimens of Fuchouia and Parafuchouia previously reported by other authors, we perform statistical analysis on morphological characters of the cranidia of Parafuchouia and Fuchouia using linear measurements. The results indicate that Parafuchouia is a junior synonym of Fuchouia, and its distinguishing features from Fuchouia can be viewed as intraspecific morphological variation. Thus, the Jialao Formation may be the lowest horizon that yields Fuchouia in the world. Although Fuchouia is widely distributed in China, the Democratic People’s Republic of Korea, India-Himalayas, Australia, Kazakhstan and other countries around the world, its occurrences span a wide range of horizons, mostly from the Ptychagnostus atavus Zone of the Drumian Stage to Lejopyge laevigata Zone of the Guzhangian Stage. Hence, it is difficult to use Fuchouia for biostratigraphic correlations. The established Fuchouia biostratigraphic zone of the Cambrian Jialao Formation in Guizhou needs to be further reviewed, and index fossils at the species level or other index fossils need to be selected to make better stratigraphic correlations with the Cambrian slope facies of South China or the Cambrian of North China platform.

国家自然科学基金(42330209, 42262003, 41962002)和贵州省科技计划项目(黔科合支撑[2020]4Y241)联合资助