Cryptomonada is a proposed super-class of Cryptists linking

Cryptophyceae The cryptophyceae are a class of algae, most of which have plastids. About 220 species are known, and they are common in freshwater, and also occur in marine and brackish habitats. Each cell is around 10–50 μm in size and flattened in shape ...

and

Goniomonadea Goniomonadea is a proposed class of cryptomonads The cryptomonads (or cryptophytes) are a group of algae, most of which have plastids. They are common in freshwater, and also occur in marine and brackish habitats. Each cell is around 10–5 ...

, which was first proposed by

Cavalier-Smith Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford. His research has led to disc ...

in 2004. He made this proposal based on three shared morphological characteristics: Presence of a

periplast The periplast is one of three types of cell-covering of three classes of algae. The ''Cryptomonads'' have the periplast covering. The '' Dinophyceae'' have a type called the amphiesma, and the ''Euglena'' covering is the pellicle. Structure The pe ...

, ejectisomes with secondary scroll, and mitochondrial

cristae A crista (; plural cristae) is a fold in the inner membrane of a mitochondrion. The name is from the Latin for ''crest'' or ''plume'', and it gives the inner membrane its characteristic wrinkled shape, providing a large amount of surface area fo ...

with flat tubules. Genetic studies as early as 1994 also supported the hypothesis that ''Goniomonas'' was sister to Cryptophyceae. A study in 2018 found strong evidence that the common ancestor of ''Cryptomonada'' was an autotrophic protist.

References

{{Taxonbar, from=Q65088966 Cryptista