Podolimirus

Podolimirus Temporal range: Late Ediacaran 557  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	† Proarticulata
Class:	† Cephalozoa
Genus:	† Podolimirus Fedonkin, 1983 [1]
Species:	† P. mirus
Binomial name
† Podolimirus mirus Fedonkin, 1983
Synonyms
Valdainia plumosa

Podolimirus is an extinct genus of proarticulates from the Ediacaran of Ukraine, and possible preserves internal organs. It is the monotypic genus, containing only Podolimirus mirus.

Discovery

The first fossil specimens of Podolimirus were found and described from the Lomoziv Member, in the Mohyliv Formation, Dniester River in Ukraine, near the deposits in the Vendian Sequence by Mikhail A. Fedokin in 1983. ^[2] The site of its discovery was below a volcanic ash bed, which has been dated to 556.78 ± 0.18 million years ago using the U-Pb method. ^{[3] [4]}

Description

Podolimirus is a rounded, quilted organism, growing up to 20 cm (7.9 in) in length. Like other proarticulates, it has a Glide reflection, meaning it is not truly symmetrical. And as is common within the White Sea area, some fossils contain what may be internal organs. The largest of these is the "dorsal quilt", possibly filled with liquid in life, with thirteen, possibly fourteen, arched units either side of a median line, making 26 altogether. These units would gradually decrease their arching and size towards the posterior end of the body. The fossils do not properly preserve a medial wall down the middle, although several do have the arched units separated down the middle, hinting at a possible medial wall down the middle. ^[4]

There is also a bifurcating structure at the front of the organism, similar to what is seen in Yorgia . These have been suggested to possible represent intestinal diverticula. ^[4] It is also currently grouped with the cephalozoan, a class of proarticulates that have fairly rounded bodies and notable "head" regions at the front of the body. ^[5]

Taphonomy

Specimens of Podolimirus may have been preserved through injections of sediment into the body after death. This would have come in the form of liquidised sediments replacing the liquids inside of the probable internal organs, although not preserving the entire body of the organism. ^[4]

See also

• Paleontology portal

• List of Ediacaran genera

References

1. Fedonkin, M. A. (1983). "Non-skeletal fauna of Podolia, Dniester River valley". In Velikanov, V. A.; Asseeva, E. A.; Fedonkin, M. A. (eds.). The Vendian of the Ukraine (in Russian). Kiev: Naukova Dumka. pp. 128–139.
2. Fedonkin, Mikhail A.; Gehling, James G.; Grey, Kathleen; Narbonne, Guy M.; Vickers-Rich, Patricia (Mar 16, 2007). The Rise and Fall of the Ediacaran Biota. JHU Press. ISBN   9781862392335 . Retrieved July 10, 2022– via Google Books.
3. Soldatenko, Y.; Albani, A. El; Ruzina, M.; Fontaine, C.; Nesterovsky, V.; Paquette, Jean-Louis; Meunier, A.; Ovtcharova, M. (2019). "Precise U-pb age constrains on the ediacaran biota in podolia, east european platform, Ukraine". Scientific Reports. 9: 1675. doi:10.1038/s41598-018-38448-9. PMC   6368556 .
4. Dzik, Jerzy; Martyshyn, Andrej (October 2015). "Taphonomy of the Ediacaran Podolimirus and associated dipleurozoans from the Vendian of Ukraine". Precambrian Research. 269: 139–146. doi:10.1016/j.precamres.2015.08.015.
5. Ivantsov, A. Yu.; Fedonkin, M. A.; Nagovitsyn, A. L.; Zakrevskaya, M. A. (September 2019). "Cephalonega, A New Generic Name, and the System of Vendian Proarticulata". Paleontological Journal. 53 (5): 447–454. doi:10.1134/S0031030119050046.