Opalinata

Opalinata is a superclass of non-phagotrophic heterokonts that unites the classes Opalinea and Blastocystea, and is the sister group to Opalomonadea.[1]

Description

When Opalinata was first erected as a taxon in 1926, it was placed as the sole class in the group "Protociliata" and considered as primitive ciliates due to the fact that they move thanks to their numerous cilia and that they both present two nuclei.[2] They were distinguished because they perform syngamy by the complete fusion of uninucleated gametes, while the rest of ciliates, forming "Euciliata" (Ciliata + Suctoria), perform syngamy through their micronuclei alone while their macronuclei dissolve.[2]

The taxon Opalinata was revised in 1996 by Cavalier-Smith and placed in Opalozoa, and is now defined by the following synapomorphies: gut parasitism and the loss of peroxisomes and phagocytosis.[3]

Phylogeny

The cladogram below shows the relationships between Opalinata and the rest of Opalozoa.[1]

Opalozoa
Placidozoa
Opalinata

Opalinea

Blastocystea

Opalomonadea  

Nanomonadea

Placididea

Bikosea

Classification

The modern taxonomy of Opalinata is as follows:[1]

References