Diversity of cnidarians and cycloneuralians in the Fortunian (early Cambrian) Kuanchuanpu Formation at Zhangjiagou, South China

• Published in: Journal of paleontology Vol. 92; no. 2; pp. 115 - 129
• Main Authors: Shao, Tiequan, Tang, Hanhua, Liu, Yunhuan, Waloszek, Dieter, Maas, Andreas, Zhang, Huaqiao
• Format: Journal Article
• Language: English
• Published: New York, USA The Paleontological Society 01.03.2018; Cambridge University Press; Paleontological Society; SEPM Society for Sedimentary Geology
• Subjects: Adults; Animal embryos; Animals; Annuli; Asia; biodiversity; Cambrian; China; cladistics; Cnidaria; Cycloneuralia; Dahe China; Dimensions; Earth and Related Environmental Sciences; Embryos; Eokinorhynchus rarus; Eopriapulites sphinx; Far East; Fortunian; Fossils; Geologi; Geology; Geovetenskap och miljövetenskap; Growth rings; Hanzhong China; Hexaconularia sichuanensis; invertebrate; Kuanchuanpu Formation; Lagerstatten; Larvae; lithostratigraphy; Lower Cambrian; Marine invertebrates; Meiobenthos; Meiofauna; Microorganisms; morphology; Natural Sciences; Naturvetenskap; Olivooides; Paleontology; Paleozoic; phylogeny; Pseudooides prima; Quadrapyrgites quadratacris; Shaanxi China; Stratigraphy; Terreneuvian; Xixiang China; Zhangjiagou China; Zoobenthos; China
• ISSN: 0022-3360; 1937-2337
• DOI: 10.1017/jpa.2017.94

The latest discovery of microfossils from the lower Cambrian (Fortunian Stage) Zhangjiagou Lagerstätte in South China are presented. This lagerstätte is rich in exceptionally preserved microfossils, including embryos of Olivooides multisulcatus, Olivooides mirabilis, and Pseudooides prima; hatched stages of O. multisulcatus, O. mirabilis, Hexaconularia sichuanensis, and Quadrapyrgites quadratacris; and cycloneuralians represented by Eopriapulites sphinx. The largest known fragment of O. mirabilis implies that its adult length can be more than 9.0mm with at least 50 annuli, and the longest known specimen of Q. quadratacris has at least 18 annuli. These unusually large specimens refute the non-feeding larvae hypothesis for Olivooides and Quadrapyrgites. Based on the current material, it is inferred that (1) early cnidarians have a high diversity in the Fortunian Stage; (2) P. prima might represent the embryonic stages of H. sichuanensis; (3) adults of Olivooides and Quadrapyrgites may have reached centimeter-scale dimensions with more than 50 annuli; (4) Olivooides and Quadrapyrgites may be better interpreted as coronate scyphozoans; (5) cycloneuralians also had a high diversity in the Zhangjiagou Lagerstätte; and (6) cycloneuralians might have originally been part of the early Cambrian meiofauna rather than belonging to the macrobenthos. Such ancestral cycloneuralians might have been Eopriapulites-like, possessing pentaradially symmetric, backward pointing, and internally hollow introvert scalids used as locomotory devices.