Chromalveolate

Chromalveolata is a eukaryote supergroup first proposed by Thomas Cavalier-Smith as a refinement of his kingdom Chromista, which was first proposed in 1981.
The origin of the Chromalveolata was thought to be a secondary endosymbiosis between a bikont (cell with two flagella) and a red alga. This union led to plastids containing chlorophyll c. In Cavalier-Smith's classification, the Chromalveolata was one of the six major groups within the eukaryotes.
The classification has been challenged.