''Ministeria vibrans'' is a bacterivorous amoeba with

filopodia Filopodia (singular filopodium) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells. Within the lamellipodium, actin ribs are known as ''microspikes'', and when they extend beyond the lame ...

that was originally described to be suspended by a flagellum-like stalk attached to the substrate. Molecular and experimental work later on demonstrated the stalk is indeed a flagellar apparatus. The amoeboid protist ''Ministeria vibrans'' occupies a key position to understand animal origins. It is a member of the

Filasterea Filasterea is a proposed basal Filozoan clade that includes '' Ministeria'' and '' Capsaspora''. It is a sister clade to the Choanozoa in which the Choanoflagellatea and Animals appeared. Originally proposed by Shalchian-Tabrizi et al. in 2008 ...

, that is the sister-group to

Choanoflagellatea The choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. Choanoflagellates are collared flagellates, having a funnel shaped collar of interconne ...

and

Metazoa Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in ...

. Two Ministeria amoebae species have been reported so far, both of them from coastal marine water samples: ''M. vibrans'' and ''M. marisola''. However, there is currently only one culture available, that of ''Ministeria vibrans.'' The life cycle of ''Ministeria'' remains unknown. Microvilli in Ministeria suggest their presence in the common ancestor of Filasterea and Choanoflagellata. The kinetid structure of Ministeria is similar to that of the choanocytes of the most deep-branching sponges, differing essentially from the kinetid of choanoflagellates. Thus, kinetid and microvilli of Ministeria illustrate features of the common ancestor of three holozoan groups: Filasterea, Metazoa and Choanoflagellata.

References

Filasterea Species described in 1997 {{Holozoa-stub