Capsaspora

Capsaspora is a single-celled eukaryote which is a symbiont in the haemolymph of the tropical freshwater snail Biomphalaria glabrata.

Taxonomy
Although it is an opisthokont, it seems not to fit in any of the established opisthokont lineages such as nucleariids or Mesomycetozoea. It is part of its own group, possibly together with Ministeria. This group is related to animals and choanoflagellates.

Species
How animals (metazoans) originated from their single-celled ancestors may still remain a major question in biology. The research team from University of Barcelona has however, come up with new findings and Capsaspora owczarzaki has recently emerged as the prime candidate.