unikont

Unikont is a proposed major grouping within the eukaryotes, named for the presumed ancestral presence of a single flagellum. The term is used in various classifications to refer to a clade that includes two large lineages: Amoebozoa, which comprises many amoeboid protists such as slime molds and lobose amoebae, and Opisthokonta, which includes animals, fungi, and related protists such as choanoflagellates. The exact composition and rank of unikonts have varied among classifications, and some smaller or poorly resolved lineages have been placed within or near the group.

A key characteristic historically associated with unikonts is the single posterior flagellum in the last common ancestor, though many descendant lineages have since lost or modified flagellar structures. In contrast, older conceptions of eukaryote diversity distinguished unikonts from Bikonta, a proposed sister grouping with different flagellar patterns. In contemporary phylogenetics, the unikont assemblage is often treated as part of a larger clade such as Amorphea, which includes Amoebozoa and Opisthokonta along with some additional lineages whose placement remains debated.

The unikont lineage encompasses a broad spectrum of life, from unicellular protists to the most familiar multicellular organisms, including the vast kingdoms of animals and fungi. This makes unikonts one of the most ecologically and evolutionarily significant divisions within the eukaryotes.

See also: Amorphea, Amoebozoa, Opisthokonta, Bikonta, Eukaryota.