title: Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota).
abstract: An overview of the controversial proposal for the major eukaryote taxon "Excavata" is presented. Excavata is predicted to include at least ten distinct groups: jakobids, Malawimonas, Trimastix, Carpediemonas, retortamonads, diplomonads, Heterolobosea, oxymonads, parabasalids and Euglenozoa. These "excavates" have broadly similar flagellar apparatus organizations, for which a "universal" terminology is provided. Most, but not all, of these organisms share a distinctive suspension-feeding groove, as well as some or all of a set of seven other proposed cytoskeletal apomorphies. Cladistic analyses of morphological data do not resolve high-level relationships within Excavata. Excavate-rich molecular phylogenies recover some robust clades, but do not support or strongly refute the monophyly of Excavata. A partial classification for excavates is presented, with phylogenetic diagnoses for Excavata and for two novel taxon names, Fornicata (Carpediemonas, retortamonads, diplomonads) and Preaxostyla (Trimastix, oxymonads).
authors.affiliation: Canadian Institute for Advanced Research, Program in Evolutionary Biology, Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1.
authors.forename: Alastair G B
authors.initials: AG
authors.lastname: Simpson
mesh_terms: D016841:Amoebida / Q000145:classification*; D000818:Animals; D003599:Cytoskeleton / Q000648:ultrastructure*; D056890:Eukaryota / Q000145:classification*; D005407:Flagella / Q000648:ultrastructure; D008854:Microscopy, Electron; D010163:Paleontology; D010802:Phylogeny