Organism does not fit into any of the known subdivisions of the animal kingdom. wo new species of 'multicellular, non-bilaterian, mesogleal animals' were collected at 400 and 1000 metres on the Australian continental slope off eastern Bass Strait and Tasmania during a cruise in 1986.
The specimens in question were not recognised in the field, but were extracted from bulk samples in the laboratory during sorting.
The authors of the article note several similarities with the bizarre and enigmatic soft-bodied life forms that lived between 635 and 540 million years ago - the span of Earth history known as the Ediacaran Period.
What are they!?
These organisms, too, have proven difficult to categorise and some researchers have even suggested they were failed experiments in multi-cellular life.
The new organisms are multicellular but mostly non-symmetrical, with a dense layer of gelatinous material between the outer skin cell and inner stomach cell layers.
The researchers did find some similarities to other animal groupings, such as the Cnidaria - the phylum that comprises corals and jellyfish - and the Ctenophora, which includes the marine organisms known as comb jellies. But the new organisms did not fulfil all the criteria required for inclusion in either of those categories.
Dr Olesen said the new animals could either be a very early branch on the tree of life, or be intermediate between two different animal phyla.