Liu Cong, Fu Dongjing, 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. 2021 Dec 9;25(1):103591. doi: 10.1016/j.isci.2021.103591. eCollection 2022 Jan 21.
Segmentation and tagmatization have contributed to the preeminent success of arthropods since their first appearance in the Cambrian. However, the exact mechanism of segmentogenesis is still insufficiently known in living and extinct groups. Here, we describe the postembryonic development of a Waptiid arthropod from the early Cambrian Chengjiang biota, South China. The new data illuminate a complex dynamic pattern of anamorphosis and epimorphosis, and a three-step process of segmentogenesis, i.e., the elongation of the terminal segment, delineation of an incipient segment, and full separation of a new segment. Compensatory growth is accomplished by rapid growth of new segments and/or generation of additional segments, which results in the trimorphism of the posterior tagma. Such complex developmental dynamics has rarely been known in the arthropod fossil record and its presence in early history helps to understand the rapid diversification of arthropods in the early Cambrian.
自节肢动物在寒武纪首次出现以来，分节和体区分化促成了它们卓越的成功。然而，无论是现存类群还是已灭绝类群，节段发生的确切机制仍知之甚少。在此，我们描述了来自中国南方早寒武世澄江生物群的一种瓦普蒂虫类节肢动物的胚后发育。新数据揭示了一种复杂的增节变态和表变态动态模式，以及一个分三步的节段发生过程，即末节延长、初始节段划定以及新节段完全分离。通过新节段的快速生长和/或额外节段的产生来实现补偿性生长，这导致了后体区的三态性。这种复杂的发育动态在节肢动物化石记录中鲜为人知，它在早期历史中的存在有助于理解寒武纪早期节肢动物的快速多样化。
