Skip to main content
    • Aa
    • Aa

Olivooides-like tube aperture in early Cambrian carinachitids (Medusozoa, Cnidaria)

  • Jian Han (a1), Guoxiang Li (a2), Xing Wang (a1), Xiaoguang Yang (a1), Junfeng Guo (a3), Osamu Sasaki (a4) and Tsuyoshi Komiya (a5)...

The early Cambrian Carinachitidae, a family in the subclass Conulata, are intriguing and important small shelly fossils. Their gently tapering, tube-shaped skeletons consist of convex faces separated from each other by broad, deep corner sulci, and they exhibit triradial, pentaradial, or predominantly tetraradial symmetry. However, the morphology of the aperture and the modes of growth of carinachitid skeletons as well as the anatomy of their soft parts are unknown. Examination of a single new, exceptionally well-preserved specimen of tetramerous Carinachites spinatus Qian, 1977, collected from the lower Cambrian Kuanchuanpu Formation in South China, reveals: (1) that its aperture is connected to a small mass of relic soft tissue and (2) that the apertural end of each of the four faces is developed into a subtriangular lappet or oral lobe that is smoothly folded toward the long axis of the tube, partially closing the tube aperture. Similarities between thorn-like spines on the faces and the oral lobes indicate that the transverse ribs were periodically displaced from the perradial portion of the aperture during formation of new ribs. In addition, the tube walls may have undergone secondary thickening during growth. The growth pattern of the tube and the spatial relationships between the tube aperture and soft parts are analogous to those of co-occurring olivooids. These findings further strengthen the previously proposed hypothesis that coeval carinachitids, olivooids, hexangulaconulariids, and Paleozoic conulariids are closely related taxa within the subphylum Medusozoa. Finally, carinachitids most likely represent an evolutionary intermediate between olivooids and hexangulaconulariids.

Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

S. Bengtson , and Z. Yue , 1997, Fossilized metazoan embryos from the earliest Cambrian: Science, v. 277, no. 5332, p. 16451648.

N. Berrill , 1949, Developmental analysis of Scyphomedusae: Biological Reviews, v. 24, no. 4, p. 393409.

K. Brood , 1995, Morphology, structure, and systematics of the conulariids: GFF, v. 117, no. 3, p. 121137.

S. Conway Morris , and M.E. Chen , 1992, Carinachitids, hexaconulariids, and Punctatus: Problematic metazoans from the early Cambrian of South China: Journal of Paleontology, v. 66, no. 3, p. 384406.

R.C. Ford , H. Van Iten , and G.R. Clark II, 2016, Microstructure and composition of the periderm of conulariids: Journal of Paleontology, v. 90, no. 3, p. 389399.

J. Han , S. Kubota , G. Li , X. Yao , X. Yang , et al., 2013, Early Cambrian pentamerous cubozoan embryos from South China: PloS One, v. 8, no. 8, p. e70741.

J. Han , S. Kubota , G. Li , Q. Ou , X. Wang , et al., 2016a, Divergent evolution of medusozoan symmetric patterns: Evidence from the microanatomy of Cambrian tetramerous cubozoans from South China: Gondwana Research, v. 31, p. 150163.

N.C. Hughes , G.O. Gunderson , and M.J. Weedon , 2000, Late Cambrian conulariids from Wisconsin and Minnesota: Journal of Paleontology, v. 74, no. 5, p. 828838.

J.D.M. Leme , M.G. Simoes , A.C. Marques , and H. Van Iten , 2008, Cladistic analysis of the suborder Conulariina Miller and Gurley, 1896 (Cnidaria, Scyphozoa; Vendian-Triassic): Palaeontology, v. 51, p. 649662.

G. Li , M. Steiner , X. Zhu , A. Yang , H. Wang , and B.D. Erdtmann , 2007, Early Cambrian metazoan fossil record of South China: Generic diversity and radiation patterns: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 254, no. 1, p. 229249.

P. Li , H. Hua , L.Y. Zhang , D.D. Zhang , X.B. Jin , and Z. Liu , 2007, Lower Cambrian phosphatized Punctatus from southern Shaanxi and their ontogeny sequence: Chinese Science Bulletin, v. 52, no. 20, p. 28202828.

Y.H. Liu , S.H. Xiao , T.Q. Shao , J. Broce , and H.Q. Zhang , 2014a, The oldest known priapulid-like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans: Evolution & Development, v. 16, no. 3, p. 155165.

Y. Liu , Y. Li , T. Shao , H. Zhang , Q. Wang , and J. Qiao , 2014b, Quadrapyrgites from the lower Cambrian of South China: Growth pattern, post-embryonic development, and affinity: Chinese Science Bulletin, v. 59, no. 31, p. 40864095.

A.C. Maloof , S.M. Porter , J.L. Moore , F.Ö. Dud , S.A. Bowring , J.A. Higgins , D.A. Fike , and M.P. Eddy , 2010, The earliest Cambrian record of animals and ocean geochemical change: Geological Society of America Bulletin, v. 122, no. 11–12, p. 17311774.

S. Puce , G. Bavestrello , A. Arillo , F. Azzini , and C. Cerrano , 2002, Morpho-functional adaptation to suspension feeding in Eudendrium (Cnidaria, Hydrozoa): Italian Journal of Zoology, v. 69, no. 4, p. 301304.

C. Sendino , K. Zágoršek , and Z. Vyhlasová , 2011, The aperture and its closure in an Ordovician conulariid: Acta Palaeontologica Polonica, v. 56, no. 3, p. 659663.

M. Steiner , G.X. Li , Y. Qian , and M.Y. Zhu , 2004, Lower Cambrian small shelly fossils of northern Sichuan and southern Shaanxi (China), and their biostratigraphic importance: Geobios, v. 37, no. 2, p. 259275.

M. Steiner , G.X. Li , Y. Qian , M.Y. Zhu , and B.D. Erdtmann , 2007, Neoproterozoic to early Cambrian small shelly fossil assemblages and a revised biostratigraphic correlation of the Yangtze Platform (China): Palaeogeography Palaeoclimatology Palaeoecology, v. 254, no. 1–2, p. 6799.

M. Steiner , Y. Qian , G. Li , J.W. Hagadorn , and M. Zhu , 2014, The developmental cycles of early Cambrian Olivooidae fam. nov. (?Cycloneuralia) from the Yangtze Platform (China): Palaeogeography, Palaeoclimatology, Palaeoecology, v. 398, p. 97124.

H. Van Iten , J. de Moraes Leme , M.G. Simões , A.C. Marques , and A.G. Collins , 2006, Reassessment of the phylogenetic position of conulariids (?Ediacaran–Triassic) within the subphylum Medusozoa (phylum Cnidaria): Journal of Systematic Palaeontology, v. 4, no. 2, p. 109118.

H. Van Iten , A.C. Marques , J.d.M. Leme , M.L. Pacheco , and M.G. Simões , 2014, Origin and early diversification of the phylum Cnidaria Verrill: Major developments in the analysis of the taxon’s Proterozoic–Cambrian history: Palaeontology, v. 57, no. 4, p. 114.

H. Van Iten , L. Muir , M.G. Simões , J.M. Leme , A.C. Marques , and N. Yoder , 2016a, Palaeobiogeography, palaeoecology and evolution of Lower Ordovician conulariids and Sphenothallus (Medusozoa, Cnidaria), with emphasis on the Fezouata Shale of southeastern Morocco: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 460, p. 170178.

H. Van Iten , J.M. Leme , M.L.A.F. Pacheco , M.G. Simões , T.R. Fairchild , F. Rodrigues , D. Galante , G.C. Boggiani , and A.C. Marques , 2016b, Origin and early diversification of phylum Cnidaria: Key macrofossils from the Ediacaran System of North America, in Goffredo, S., and Dubinsky, Z., eds, The Cnidaria, Past, Present and Future: Berlin, Springer, p. 3140. doi: 10.1007/978-3-319-31305-4_3.

B. Werner , 1966, Stephanoscyphus (Scyphozoa, Coronatae) und seine direkte Abstammung von den fossilen Conulata: Helgoländer Wissenschaftliche Meeresuntersuchungen, v. 13, no. 4, p. 317347.

B. Werner , 1973, New investigations on systematics and evolution of the class Scyphozoa and the phylum Cnidaria: Publications of the Seto Marine Biology Lab, v. 20, p. 3561.

K. Yasui , J.D. Reimer , Y. Liu , X. Yao , D. Kubo , D. Shu , and Y. Li , 2013, A diploblastic radiate animal at the dawn of Cambrian diversification with a simple body plan: Distinct from Cnidaria? PLoS One, v. 8, no. 6, p. e65890.

H. Zhang , S. Xiao , Y. Liu , X. Yuan , B. Wan , A. Muscente , T. Shao , H. Gong , and G. Cao , 2015, Armored kinorhynch-like scalidophoran animals from the early Cambrian: Scientific Reports, v. 5, article no. 16521.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Paleontology
  • ISSN: 0022-3360
  • EISSN: 1937-2337
  • URL: /core/journals/journal-of-paleontology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Altmetric attention score

Full text views

Total number of HTML views: 2
Total number of PDF views: 33 *
Loading metrics...

Abstract views

Total abstract views: 74 *
Loading metrics...

* Views captured on Cambridge Core between 29th June 2017 - 25th July 2017. This data will be updated every 24 hours.