Eoandromeda octobrachiata (lat.) Is a representative of the Ediacar biota , the systematic position of which is not defined . Inhabited 580-550 million years ago. It was a rounded body from 1 to 4 cm in diameter with eight tentacles twisted spirally both clockwise and counterclockwise. The name is derived from other Greek. ἕως “dawn” and the name of the bright spiral galaxy in Andromeda due to the antiquity of the organism and the similarity of the fossil form with the shape of the galaxy.
| † Eoandromeda octobrachiata | |||||||||||||||||||||||||||||||||||||||||
 Reconstruction | |||||||||||||||||||||||||||||||||||||||||
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Eoandromeda octobrachiata | |||||||||||||||||||||||||||||||||||||||||
| Geochronology 580-550 Ma
◄ Nowadays◄ Cretaceous-Paleogene extinction◄ Triassic extinction◄ Mass Permian Extinction◄ Devonian extinction◄ Ordovician-Silurian extinction◄ Cambrian explosion | |||||||||||||||||||||||||||||||||||||||||
Described from samples from the Ediacar Mountains in Australia and from the Doushanto Formation in China [1] . Supposedly were ubiquitous [2] .
Content
Theories
Researchers led by paleontologist Feng Tang of the Chinese Academy of Geological Sciences in Beijing believe that eoandromeda is an ancient ctenophore . The authors of the article believe that 8 rows of formations are similar to rowing plates with a spiral pattern in the arrangement of these rows. However, in such an organism biradial symmetry is not observed, and there is no mouth and tentacles [3] .
See also
- List of Ediacar clans
Notes
- ↑ Maoyan Zhu, James G. Gehling, Shuhai Xiao, Yuanlong Zhao, Mary L. Droser. Eight-armed Ediacara fossil preserved in contrasting taphonomic windows from China and Australia (Eng.) // Geology: journal. - 2008. - Vol. 36 , no. 11 . - P. 867-870 . - DOI : 10.1130 / G25203A.1 .
- ↑ Wang Yue, Wang Xunlian, Huang Yuming. Megascopic Symmetrical Metazoans from the Ediacaran Doushantuo Formation in the Northeastern Guizhou, South China // Journal of China University of Geosciences: journal. - 2008 .-- June ( vol. 19 , no. 3 ). - P. 200-206 . - ISSN 1002-0705 . - DOI : 10.1016 / S1002-0705 (08) 60039-4 .
- ↑ Feng Tang, Stefan Bengtson, Yue Wang, Xun-lian Wang and Chong-yu Yin. Eoandromeda and the origin of Ctenophora // Evolution & Development. - September / October 2011. - Vol. 13, No. 5 . - P. 408-414. - DOI : 10.1111 / j.1525-142X.2011.00499.x . - PMID 23016902 .
Links
- Amy Maxmen. Ancient sea jelly makes tree of life wobble . nature.com (September 7, 2011).
- Jennifer Viegas. Eight-armed animal preceded dinosaurs . ABC Science (November 4, 2008).