Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China.
Sci Rep. 2017 Sep 11;7(1):11117. doi: 10.1038/s41598-017-11610-5.
Cambrian marine ecosystems were dominated by arthropods, and more specifically artiopods. Aglaspidids represent an atypical group amongst them, not the least because they evolved and rapidly diversified during the late Cambrian, a time interval between the two diversification events of the Early Palaeozoic. Recent phylogenetic analyses have retrieved aglaspidids within the Vicissicaudata, a potentially important, but difficult to define clade of artiopods. Here we describe a new aglaspidid from the Furongian Guole Konservat-Lagerstätte of South China. This taxon displays a pretelsonic segment bearing non-walking appendages, features as-yet known in all vicissicaudatans, but aglaspidids. A new comprehensive phylogenetic analysis provides strong support for the legitimacy of a monophyletic clade Vicissicaudata, and demonstrates the pertinence of new characters to define Aglaspidida. It also motivates important changes to the systematics of the phylum, including the elevation of Artiopoda to the rank of subphylum, and the establishment of a new superclass Vicissicaudata and a new aglaspidid family Tremaglaspididae. Two diversification pulses can be recognized in the early history of artiopods - one in the early Cambrian (trilobitomorphs) and the other in the late Cambrian (vicissicaudatans). The discrepancy between this pattern and that traditionally depicted for marine invertebrates in the Early Palaeozoic is discussed.
寒武纪海洋生态系统以节肢动物为主，尤其是有颚类。Aglaspidida 是它们中一个非典型的群体，尤其是因为它们在晚寒武世进化并迅速多样化，而这个时期正好介于早古生代的两个多样化事件之间。最近的系统发育分析将 Aglaspidida 归入 Vicissicaudata 中，这是一个潜在重要但难以定义的有颚类分支。本文描述了一个来自华南芙蓉统 GuoLe 特异埋藏化石库的新 Aglaspidida。这个分类单元具有带非步行附肢的前鳃节，这是所有 Vicissicaudatans 和 Aglaspidida 所共有的特征。一个新的综合系统发育分析为单系的 Vicissicaudata 分支提供了强有力的支持，并证明了新特征对于定义 Aglaspidida 的相关性。它还促使门的系统发育发生了重要变化，包括将节肢动物提升为亚门的地位，以及建立一个新的超类 Vicissicaudata 和一个新的 Aglaspidida 科 Tremaglaspididae。在节肢动物的早期历史中可以识别出两个多样化脉冲——一个在早寒武世（三叶虫类），另一个在晚寒武世（Vicissicaudatans）。讨论了这种模式与传统上描绘的早古生代海洋无脊椎动物模式之间的差异。
