Pteridinium

taxobox|name=Pteridinium
fossil_range=Ediacaran
regnum="incertae sedis"
genus="Pteridinium"
genus_authority=Gürich (1930)

"Pteridinium" is a fossil found in a number of Precambrian deposits worldwide. It is a member of the Ediacaran biota.

The fossil is common in late Precambrian deposits in South Australia, Namibia, and the White Sea region of Russia. It has also been found in North Carolina and is reported from California and the Northwest Territories of Canada. It has a three-lobed body which is generally smashed flat such that only two lobes are visible. Each lobe consists of a number of parallel ribs extending back to the main axis where the three lobes come together. Even on well-preserved specimens, there is no sign of a mouth, anus, eyes, legs, antennae, or any other appendages or organs. Specimens found in what is thought to be life positions indicate that the animal rested on — or possibly in — the sediment in shallow seas. No tracks are known that would seem to be consistent with a moving "Pterinidium". It is unclear whether it made food via photosynthesis, or somehow extracted nourishment from seawater despite the absence of any obvious way to ingest or eliminate sea water.

"Pteridium simplex" was originally described by Georg Gürich in 1930 published in "Zeitschrift der Deutschen Geologischen Gesellschaft" vol.82 p.637. This name was already used back in 1777 by Scopoli and so it was changed to Pteridinium in 1933.

It was originally thought that "Pteridinium" might be a primitive cnidarian, but it appears that it is, at best, only very distantly related to any known cnidarian. Its relation to other known Vendazoa is no clearer. There are no identified related forms, although there is some vague resemblance to other Vendian forms such as "Dickinsonia" and "Spriggina" that share some of its enigmatic characteristics. "Pteridinium" has no known descendants other than possibly an enigmatic Cambrian form known as "Emmonaspis".

External links

* [http://www.ucmp.berkeley.edu/vendian/pteridinium.html Vendian Animals: Pteridinium] , at University of California Museum of Paleontology
* [http://www.ucmp.berkeley.edu/vendian/pter.gifPhotograph]