Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota) - PubMed

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).

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