Liu Cong, Fu Dongjing, Wu Yu, Zhang Xingliang
State Key Laboratory of the Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University, Xi'an 710069, China.
Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, Nanjing 210008, China.
iScience. 2024 Jul 11;27(8):110443. doi: 10.1016/j.isci.2024.110443. eCollection 2024 Aug 16.
The origin and evolution of trilobated body plan of the Artiopoda, a group of epibenthic euarthropods from Cambrian Lagerstätten, remain unclear. Here we examine old and new specimens of , one of euarthropods from the Chengjiang biota, revealing new morphological details and revising its taxonomy. possesses an elongate body with a five-segmented head, a thorax with 13-15 tergites, and a three-segmented pygidium with well-defined axial region. The ventral morphology includes paired stalked eyes, one fleshy antenna pair, the following homogeneous head and thoracic appendages, each with an annular proximal-element, an articulated stenopodous branch and a lamellar flap, and the pygidial appendages solely consisting of lamellar flaps. Cladistic analyses resolved as the basal-most member of the Artiopoda, offering a hypothesis of the initial origin of trilobation in the pygidium. The new data, in conjunction with the presence of the elongated body plan across major lineages of euarthropods, suggest a convergent evolution of this trait.
三叶形亚纲是一类来自寒武纪化石库的表栖真节肢动物，其三叶形身体结构的起源和演化仍不清楚。在这里，我们研究了澄江生物群中一种真节肢动物的新旧标本，揭示了新的形态细节并修订了其分类。该物种拥有细长的身体，头部有五节，胸部有13 - 15个背板，尾节有三节，轴向区域清晰。腹面形态包括成对的柄眼、一对肉质触角、随后的均匀的头部和胸部附肢，每个附肢都有一个环形近端元件、一个有关节的窄足分支和一个片状瓣，尾节附肢仅由片状瓣组成。分支系统分析将该物种解析为三叶形亚纲最基部的成员，为尾节三叶化的最初起源提供了一个假设。新数据，连同真节肢动物主要类群中细长身体结构的存在，表明了这一特征的趋同进化。
