Incertae sedis

term to indicate an uncertain taxonomic position

Parakaryon myojinensis, also known as the Myojin parakaryote, is a highly unusual species of single-celled organism known only from a single specimen, described in 2012. It has features of both prokaryotes and eukaryotes but is apparently distinct from either group, making it unique among organisms discovered thus far. It is the sole species in the genus Parakaryon. It is part of the domain Parakarya.

viroid-like element

Aspidella is also a homonym for the mushroom genus Saproamanita.

Cyclomedusa is a circular fossil of the Ediacaran biota; it has a circular bump in the middle and as many as five circular growth ridges around it. Many specimens are small, but specimens in excess of 20 cm are known. The concentric disks are not necessarily circular, especially when adjacent individuals interfere with each other's growth. Many radial segment lines — somewhat pineapple-like — extend across the outer disks. A few specimens show what might be a stem extending from the center in some direction or other.

Mawsonites is a fossil genus dating to the Ediacaran Period, from 635–539 million years ago during the Precambrian era. The type species is Mawsonites spriggi. The names derive from South Australian geologists Douglas Mawson and Reg Sprigg.

Beltanelliformis is a cyanobacterial/putative algae genus of discoid fossil that lived during the Ediacaran period around 635 to 538.8 million years ago. It contains two species, B. brunsae and B. minutae. It is sometimes ascribed to the Ediacaran Biota. Depending on its preservation, it is sometimes referred to as Nemiana or Beltanelloides.