Excavata

Excavata is a proposed grouping of eukaryotes that includes many organisms with a feeding groove. Evidence for its evolutionary unity remains disputed.

Eukaryote: An organism whose cells contain a nucleus and other membrane-bound structures. Excavata is proposed as a major grouping within this broad domain of life.
Mitochondrion: A membrane-bound organelle that generates cellular energy through aerobic respiration in most eukaryotes. Mitochondrial forms and losses complicate comparisons among excavate lineages.
Euglenozoa: A eukaryotic group that includes euglenids, kinetoplastids, and related flagellates. This well-recognized lineage has often been included within Excavata.
Diaphoretickes: A proposed eukaryotic supergroup that includes lineages such as Archaeplastida, SAR, and Cryptista. It represents a different major branch in broad eukaryote classification schemes.
Eukaryote classification: The organization of eukaryotes into taxonomic groups based on evolutionary relationships and shared traits. Excavata’s placement changes with competing schemes for classifying eukaryotes.
Hydrogenosome: A mitochondrion-related organelle that produces hydrogen and ATP under anaerobic conditions. Some proposed excavates use this modified organelle instead of typical aerobic mitochondria.
Kinetoplastid: A flagellated eukaryote characterized by a kinetoplast, a DNA-rich region in its mitochondrion. Kinetoplastids demonstrate the group’s breadth, including important parasites.
Amorphea: A eukaryotic supergroup containing animals, fungi, amoebozoans, and their relatives. Its strongly supported membership contrasts with the uncertain unity of Excavata.
Phylogenetics: The study of evolutionary relationships among organisms using shared characteristics and molecular evidence. Phylogenetic analyses test whether Excavata forms a single evolutionary lineage.
Mitosome: A reduced mitochondrion-related organelle that performs limited functions and does not generate ATP. Its presence in some lineages illustrates how far mitochondrial descendants can diverge.

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SAR supergroupCompared with: It is another proposed deep eukaryotic grouping, with a less settled status than SAR.