Nemiana is a genus of simple, sessile organisms, containing just one species, N. simplex. They are one of the most commonly found Ediacaran

Ediacaran

The Ediacaran Period , named after the Ediacara Hills of South Australia, is the last geological period of the Neoproterozoic Era and of the Proterozoic Eon, immediately preceding the Cambrian Period, the first period of the Paleozoic Era and of the Phanerozoic Eon...

 organisms. While they have been found worldwide, their main locality are the sandstone shales near the White Sea

White Sea

The White Sea is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is surrounded by Karelia to the west, the Kola Peninsula to the north, and the Kanin Peninsula to the northeast. The whole of the White Sea is under Russian sovereignty and considered to be part of...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

.

Taxonomy

Nemiana simplex has given taxonomists great trouble due to its simple nature. When the species was first discovered it was placed in incertae sedis, however since then, a combination of well preserved specimens and new techniques that have allowed scientists to examine the creature's body structure, have given the creature anatomical links to jellyfish and was subsequently placed in with the other extinct colenterates. It has been suggested that N. simplex is in fact related to the protoctists and is sometimes thought to be simply a conglomeration of green algae similar to a stromatolite

Stromatolite

Stromatolites or stromatoliths are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria ....

, however, this theory is disputed.

Morphology

Nemiana simplex has one of the most simple body plans of all Ediacarans. It consists of a jelly-like sac filled with its various internal structures. However some fossils possess strange markings on top which suggests that the species had small tentacles.

Lifestyle and reproduction

It is possible that this creature did move and fed upon the algal mats of the precambrian oceans. However most scientists agree that this creature was in fact more similar to a sea anenome and burrowed, leaving its top half and hypothetical tentacles in the open water possibly for feeding. Scientists think that this organism reproduced asexually, but some believe that it released its zygotes into the water or produced spores or polyps.

External links

• Ediacara Assemblage University of Bristol