https://en.wikipedia.org/wiki/Parakaryon_myojinensis>Parakaryon myojinensis, also known as the Myojin parakaryote, is a highly unusual species of single-celled organism known 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 so far discovered. It is the sole species in the genus Parakaryon.>It is not clear whether P. myojinensis can be classified as a eukaryote or a prokaryote, the two categories to which all other cellular life belongs. Like eukaryotes and unlike prokaryotes, P. myojinensis has a nucleus and endosymbionts. However, the nuclear membrane is a single layer, not a double layer as in eukaryotes, and the DNA is stored in filaments rather than linear chromosomes. Furthermore, there is no endoplasmic reticulum, Golgi apparatus, cytoskeleton, mitochondria, or nuclear pores. Ribosomes are found not only in the cytoplasm but also in the nucleus. Adding to the difficulties of classification, only one instance of this organism has been discovered to date, and so scientists have not been able to study it further.
Well, what's the consen/sci/s? Missing link between archaea and eukaryotes? Eukaryote that lost some of its features for whatever reason? Prokaryotes that evolved those features independently? Hoax? An entirely new domain of life?