''Creolimax fragrantissima'' is a single-celled
protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the e ...
that occupies a key phylogenetic position to understand the origin of animals. It was isolated from the digestive tract of some marine invertebrates, mainly from the
peanut worm
The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of unsegmented marine annelid worms. The name ''Sipuncula'' is from the genus name ''Sipunculus'', and comes from the Latin ' ...
, collected from the Northeast Pacific.
Taxonomy
''Creolimax'' is a member of the
Ichthyosporea
The Mesomycetozoea (or DRIP clade, or Ichthyosporea) are a small group of Opisthokonta in Eukaryota (formerly protists), mostly parasites of fish and other animals.
Significance
They are not particularly distinctive morphologically, appearing i ...
, which is the earliest branching
holozoa
Holozoa is a group of organisms that includes animals and their closest single-celled relatives, but excludes fungi. ''Holozoa'' is also an old name for the tunicate genus
Genus ( plural genera ) is a taxonomic rank used in the biological ...
n lineage.
Applications
''Creolimax'' is one of the few ichthyosporeans that is culturable. It can be easily grown in the lab through cycles of asexual reproduction. Each cycle comprises two stages. First, a growth stage, in which the cells, which are non-motile, contain several nuclei, a cell wall, and a big central vacuole. This stage is followed by a release of motile amoeboids, which are mono-nucleated and non-dividing.
Characterising those two stages can help to elucidate the development of specific cell types in multicellular animals.
Moreover, it has been shown that ''Creolimax'' uses a complex gene regulation system, including long non-coding RNAs and exon skipping alternative splicing, which were normally associated with multicellular animals.
References
{{Taxonbar, from=Q30715539
Mesomycetozoea