Cephalozoa
Temporal range: Ediacaran
Fossil of Yorgia waggoneri, a cephalozoan found on the shores of the White Sea.
Scientific classification
Kingdom:
Animalia
Phylum:
†Proarticulata
Class:
†Cephalozoa

Fedonkin, 1985
Subtaxa

Cephalozoa[1] are an extinct class of primitive segmented marine organisms within the Phylum Proarticulata from the Ediacaran period. They possessed bilateral symmetry and were characterized by a thin, rounded body.

Description

Yorgia waggoneri organization diagram.

Unlike the other classes of proarticulates, the segmentation of the body is not complete and shows a "head" with fine distribution channels. Some species of the Yorgiidae family also show some asymmetry.[3][4][5]

They were discovered in Russia near the White Sea in the Arkhangelsk region, where they lived during the Ediacaran, approximately 635 to 540 Ma (millions of years ago).

Taxonomy

Cephalozoa includes the families Yorgiidae and Sprigginidae:

Yorgiidae

Sprigginidae

The genus Andiva sometimes includes Cephalozoa:

Fossil of Andiva ivantsovi.

Recent studies indicate that the family Yorgiidae could be included or closely related to the class Vendiamorpha.[7]

See also

References

  1. 1 2 Ivantsov, A. Y. (2001). "Vendia and Other Precambrian "Arthropods"". Paleontological Journal. pp. 335–343.
  2. ↑ Mikhail A. Fedonkin, James G. Gehling, Kathleen Grey, Guy M. Narbonne, and Patricia Vickers-Rich. Foreword by Arthur C. Clarke. (2008) "The Rise of Animals. Evolution and Diversification of the Kingdom Animalia"
  3. ↑ Ivantsov, A. Yu (2004). "New Proarticulata from the Vendian of the Arkhangel'sk Region" (PDF). Paleontological Journal. pp. 247–253.
  4. ↑ Ivantsov, A. Y.; Malakhovskaya, Y. E.; Serezhnikova, E. A. (2004). "Some Problematic Fossils from the Vendian of the Southeastern White Sea Region" (PDF). Paleontological Journal. pp. 1–9. Archived from the original (PDF) on 2007-07-04. Retrieved 2021-08-11.
  5. ↑ Ivantsov, A. Y. (2004) "Vendian Animals in the Phylum Proarticulata" Archived 2012-03-21 at the Wayback Machine. The Rise and Fall of the Vendian Biota. IGSP Project 493. Abstracts. Prato, Italy, p. 52.
  6. ↑ Ivantsov, Andrey Yu (2007). "Small Vendian transversely Articulated fossils". Paleontological Journal. p. 113. doi:10.1134/S0031030107020013.
  7. ↑ "Fossilworks: Vendiamorpha". fossilworks.org. Retrieved 17 December 2021.


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