title: Multigene phylogeny resolves deep branching of Amoebozoa.
abstract: Amoebozoa is a key phylum for eukaryote phylogeny and evolutionary history, but its phylogenetic validity has been questioned since included species are very diverse: amoebo-flagellate slime-moulds, naked and testate amoebae, and some flagellates. 18S rRNA gene trees have not firmly established its internal topology. To rectify this we sequenced cDNA libraries for seven diverse Amoebozoa and conducted phylogenetic analyses for 109 eukaryotes (17-18 Amoebozoa) using 60-188 genes. We conducted Bayesian inferences with the evolutionarily most realistic site-heterogeneous CAT-GTR-Γ model and maximum likelihood analyses. These unequivocally establish the monophyly of Amoebozoa, showing a primary dichotomy between the previously contested subphyla Lobosa and Conosa. Lobosa, the entirely non-flagellate lobose amoebae, are robustly partitioned into the monophyletic classes Tubulinea, with predominantly tube-shaped pseudopodia, and Discosea with flattened cells and different locomotion. Within Conosa 60/70-gene trees with very little missing data show a primary dichotomy between the aerobic infraphylum Semiconosia (Mycetozoa and Variosea) and secondarily anaerobic Archamoebae. These phylogenetic features are entirely congruent with the most recent major amoebozoan classification emphasising locomotion modes, pseudopodial morphology, and ultrastructure. However, 188-gene trees where proportionally more taxa have sparser gene-representation weakly place Archamoebae as sister to Macromycetozoa instead, possibly a tree reconstruction artefact of differentially missing data.
authors.affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom. Electronic address: tom.cavalier-smith@zoo.ox.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Cavalier-Smith
authors.affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Fiore-Donno
authors.affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.
authors.forename: Ema
authors.initials: E
authors.lastname: Chao
authors.affiliation: Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg State University, Saint-Petersburg, Russia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kudryavtsev
authors.affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.
authors.forename: Cédric
authors.initials: C
authors.lastname: Berney
authors.affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Snell
authors.affiliation: Department of Zoology, University of Oxford, Oxford, United Kingdom.
authors.forename: Rhodri
authors.initials: R
authors.lastname: Lewis
mesh_terms: D056894:Amoebozoa / Q000145:classification*; D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D015723:Gene Library; D016013:Likelihood Functions; D008957:Models, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA
keywords: Amoebae phylogenomics; Eukaryote-wide phylogeny; Himatismenida; Nolandella; Semiconosia; Varipodida