Capsaspora

This amoeboid protist has been pivotal to unraveling the nature of the unicellular ancestor of animals, which has been proved to be much more complex than previously thought.

[8] Under culture conditions, C. owczarzaki’s filopodial cells crawl attached to the substrate, with active replication until the end of the exponential growth phase.

[6][7] Cystic cells measure 4 to 5 μm with a double wall: the outer thin, irregular and loosely attached; and the inner thicker, smooth.

[12][13][14] Finally, a multi-gene phylogenetic analysis with several opisthokont taxa clearly showed that C. owczarzaki is not a nucleariid, but part of the Holozoa.

C. owczarzaki not only parasitizes the intermediate host of S. mansoni but also attacks and kills the sporocysts of the flatworm living inside the snail.

Figure 1: Capsaspora 's phylogenetic tree