Creolimax fragrantissima

creolimax fragrantissimaCreolimax fragrantissima is a single-celled protist that occupies a key position to understand the origin of animals. It was isolated from the digestive tract of some marine invertebrates, mainly from the peanut worm, collected from the Northeast Pacific (Marshall et al, 2008)  Creolimax is a member of the Ichthyosporea clade, within the Teretosporea, which is the earliest branching holozoan lineage (Torruella et al, 2012).

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. 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 (Marshall et al, 2008; de Mendoza et al, 2015). 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 (de Mendoza et al, 2015).

Given all the aforementioned characteristics discussed, it is clear that Creolimax is not only a fascinating organism to be studied, but also one that might yield critical insight into the evolution of animal multicellularity.


-de Mendoza, A., Hiroshi Suga, Jon Permanyer, Manuel Irimia, Iñaki Ruiz-Trillo. (2015)
Complex transcriptional regulation and independent evolution of fungal-like traits in a relative of animals.
eLife 2015;10.7554/eLife.08904

-Marshall, W. L., Celio, G., McLaughlin, D. J., & Berbee, M. L. (2008). Multiple Isolations of a Culturable, Motile Ichthyosporean (Mesomycetozoa, Opisthokonta), Creolimax fragrantissima n. gen., n. sp., from Marine Invertebrate Digestive Tracts. Protist, 159(3), 415–433.

-Torruella, G., Romain Derelle, Jordi Paps, B. Franz Lang, Andrew J Roger, Kamran Shalchian-Tabrizi & Iñaki Ruiz-Trillo. (2012)
Phylogenetic relationships within the Opisthokonta based on phylogenomic analyses of conserved single copy protein domains.
Molecular Biology and Evolution 29(2): 531-544.