Internal Microanatomy and Zoological Affinity of the Early Cambrian Olivooides

• Published in: Acta geologica Sinica (Beijing) Vol. 90; no. 1; pp. 38 - 65
• Main Authors: Jian, HAN, Guoxiang, LI, Shin, KUBOTA, Qiang, OU, Sho, TOSHINO, Xing, WANG, Xiaoguang, YANG, Kentaro, UESUGI, Hoshino, MASATO, Osamu, SASAKI, Harumasa, KANO, Tomohiko, SATO, Tsuyoshi, KOMIYA
• Format: Journal Article
• Language: English
• Published: Richmond Blackwell Publishing Ltd 01.02.2016; Wiley Subscription Services, Inc; Early Life Institute and Department of Geology and State Key Laboratory of Continental Dynamics,Northwest University, 229 Taibai Road, Xi'an 710069, China%State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences, Nanjing 210008, China%Seto Marine Biological Laboratory, Field Science Education and Research Center, Kyoto University,Shirahama, Nishimuro, Wakayama 649-2211, Japan%Early Life Evolution Laboratory, School of Earth Sciences and Resources, China,University of Geosciences, Beijing 100083, China%Graduate School of Fisheries Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa 252-0373, Japan
• Edition: English ed.
• Subjects: Affinity; Apertures; Bifurcations; Cambrian; cnidarians; Cubomedusae; cubozoan; Cysts; early Cambrian; Embryos; Eyes; Fossils; Kuanchuanpu Formation; Marine; Muscles; Olivooides; periderm; Zoological; China, People's Rep; periderm; cnidarians; Kuanchuanpu Formation; early Cambrian; cubozoan; Embryos
• ISSN: 1000-9515; 1755-6724
• DOI: 10.1111/1755-6724.12641

The early Cambrian pentamerous microfossil Olivooides/Punctatus in South China, which is characterized by a diagnostic stellate tubular apex, has been well‐known for its almost complete development sequence that can be confidently traced from embryos and hatched juveniles, to conical adults. However, its zoological affinity remains highly controversial. Here we describe the internal microanatomic structures of the soft‐body inside the peridermal theca of Olivooides multisulcatus Qian, 1977, including interradial pairs of tentacles, adradial and perradial fremila, perradial oral marginal lappets and twins of perradial gastric saccule‐like humps as well as a circular velarium with striated coronal muscles. Particularly, one specimen shows bifurcated velarial canals along the bell aperture. Both the components of the soft‐body and the external theca (or cyst) are arranged in perfect pentaradial symmetry. These characteristics are more compatible with those of living cubomedusans and co‐occurring Cambrian athecate embryonic cubozoans. Concerning the presence of peridermal theca, Olivooides most likely represents an extinct thecate stem‐group cubomedusae but devoid of both perradial eyes and specialized pedalia. The well‐grown soft body inside the peridermal tube displays a set of mixed features of both polyp and medusa.