Anatomy and affinities of a new 535-million-year-old medusozoan from the Kuanchuanpu Formation, South China

Xing Wang, Jian Han, Jean Vannier, Qiang Ou, Xiaoguang Yang, Kentaro Uesugi, Osamu Sasaki, Tsuyoshi Komiya

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


We describe here Sinaster petalon gen. et sp. nov., a new embryonic form from the c. 535 million-year-old Kuanchuanpu Formation of South China (Ningqiang, Shaanxi Province). The excellent three-dimensional, phosphatic preservation of these microfossils allowed us to use x-ray microtomographic techniques to make accurate reconstructions of their internal structures and to compare their anatomy point-by-point with that of extant cnidarians and other animal groups. Sinaster petalon has anatomical features typical of extant Medusozoa (Cnidaria), such as coronal muscles, perradial and adradial frenula, interradial septa, accessory septa, gonad-lamellae, tentacle buds and perradial pockets. Although Sinaster cannot be straightforwardly assigned to any crown-group within Medusozoa, the presence of marginal lappets and endodermal lamellae suggests that it is closer to Cubozoa and Scyphozoa than to any other group of modern cnidarians. The tentative placement of Sinaster within the stem-group Cubozoa is justified by the presence of a velarium supported by a frenulum. The cubozoan affinities of Sinaster are also supported by cladistic analysis.

Original languageEnglish
Pages (from-to)853-867
Number of pages15
Issue number6
Publication statusPublished - 2017 Nov


  • Cnidaria
  • Cubozoa
  • Early Cambrian
  • Kuanchuanpu Formation
  • embryo
  • periderm

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Palaeontology


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