Excavata is a major supergroup of
unicellular organisms belonging to the
domain Eukaryota. Introduced by
Thomas Cavalier-Smith in 2002 as a new phylogenetic category, it contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans. Excavates were formerly considered to be included in the now obsolete
Protista kingdom. They are classified based on their flagellar structures, and they are considered to be the oldest members (basal lineage) of
flagellated organisms.
