Abstract Limestones of the Xihaoping Member of the Dengying Formation in the Xiaoyangba section, South China, yield the oldest known Cambrian brachiopod–trilobite association. In this member, the trilobite Parabadiella cf. huoi co-occurs with the new brachiopod species Eoobolus incipiens sp. nov. The association provides potential for correlation of lower Cambrian successions and gives novel insights into the origin, palaeobiogeographic distribution and early evolution of linguliform brachiopods. Parabadiella occurs in shallow marine clastic and carbonate rocks in South China, demonstrating a broad distribution for this taxon. The new discovery indicates an early Chiungchussuan age (Parabadiella trilobite Zone, Cambrian Age 3) for the longstanding problematic Xihaoping Member. Furthermore, this earliest Parabadiella–Eoobolus association helps to establish close links with the oldest known trilobite–brachiopod assemblage from the upper Micrina etheridgei Zone (Parabadiella huoi trilobite Zone) in Australia. Eoobolus incipiens represents one of the earliest known linguliform brachiopods, with a distinctive mixture of characters shared with both problematic tommotiids, as well as paterinide, lingulide and acrotretide brachiopods, indicating that these features may be plesiomorphic for the Linguliformea. An age-constrained dispersal mode for early lingulate brachiopods is proposed, indicating that the Subphylum Linguliformea may have originated in East Gondwana and South China during Cambrian Age 3, and only subsequently dispersed to other major Cambrian palaeocontinents (e.g. Siberia, Laurentia, Antarctica, Baltica, Avalonia, West Gondwana, North China) during the late stage of the Cambrian evolutionary radiation of animals.

中文翻译：

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华南最古老的寒武纪三叶虫-腕足动物群

摘要 华南小羊坝剖面灯影组西昊坪段的石灰岩产生了已知最古老的寒武纪腕足动物-三叶虫组合。在该成员中，三叶虫 Parabadiella 参见。huoi 与新的腕足类动物 Eoobolus incipiens sp 共同出现。十一月 该关联为下寒武纪序列的相关性提供了潜力，并为舌状腕足类的起源、古生物地理分布和早期进化提供了新的见解。Parabadiella 出现在华南浅海碎屑岩和碳酸盐岩中，表明该分类群分布广泛。这一新发现表明长期存在问题的西昊坪段处于早期的琼楚索时代（Parabadiella trilobite Zone，寒武纪3）。此外，这种最早的 Parabadiella-Eoobolus 组合有助于与澳大利亚最古老的三叶虫-腕足动物组合建立密切的联系，这些组合来自澳大利亚 Micrina etheridgei 区（Parabadiella huoi 三叶虫区）。Eoobolus incipiens 代表了已知最早的舌状腕足类动物之一，具有与有问题的拟片类以及 paterinide、lingulide 和 acrotretide 腕足类共有的独特特征混合，表明这些特征可能是舌形腕足类的拟形。提出了早期舌状腕足动物的年龄限制扩散模式，表明舌形亚门可能在寒武纪 3 期起源于冈瓦纳东部和华南地区，随后才分散到其他主要寒武纪古大陆（例如西伯利亚、劳伦大陆、南极洲、波罗的海） , 阿瓦隆尼亚,