Protist, Vol. 162, 332–372, April 2011 http://www.elsevier.de/protis Published online date 4 February 2011 ORIGINAL PAPER Novel Cultured Protists Identify Deep-branching Environmental DNA Clades of Cercozoa: New Genera Tremula, Micrometopion, Minimassisteria, Nudiﬁla, Peregrinia Alexis T. Howe a,1 , David Bass b,1,2 , Josephine M. Scoble a , Rhodri Lewis a , Keith Vickerman c , Hartmut Arndt d , and Thomas Cavalier-Smith a a Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK b Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK c Division of Environmental and Evolutionary Biology, University of Glasgow, Glasgow G12 8QQ, UK d Department of General Ecology and Limnology, Zoological Institute, University of Cologne, 50923 Cologne, Germany Submitted April 25, 2010; Accepted September 6, 2010 Monitoring Editor: Michael Melkonian We describe three new orders of ﬁlosan Cercozoa, ﬁve new deep-branching genera, eight new species of Thaumatomonas, Reckertia, Spongomonas, Rhogostoma, Agitata, Neoheteromita and Paracercomonas, sequence their 18S rDNA, and construct 18S rDNA trees for 148 Cercozoa. Our phylogeny indicates that Filosa were ancestrally gliding ﬂagellates; non-ﬂagellate ﬁlose amoebae evolved from them ﬁve times independently. The new genera are more closely related to environ- mental DNA sequences than cultured organisms. Tremula longiﬁla, a zooﬂagellate glider on both ﬂagella (unlike other Cercozoa), is the most divergent ﬁlosan (Tremulida ord. n.). Micrometopion nutans is a eukaryote-eating gliding zooﬂagellate like Metopion and Metromonas. Minimassisteria diva is a widespread trimorphic marine amoeboﬂagellate granoﬁlosan. Peregrinia clavideferens, a non-testate, scale-bearing, ﬁlose amoeba, branches deeply in Thaumatomonadida, which are probably sisters to Spongomonadida. Nudiﬁla producta is a ﬁlose amoeboﬂagellate related to Clautriavia and Marimona- dida (ord. n., e.g. Pseudopirsonia, Auranticordis). We substantially revise Imbricatea, now including Spongomonadida, and Thecoﬁlosea to include Phaeodaria. Thecoﬁlosea and Imbricatea and The- coﬁlosea are sisters, both arguably ancestrally rigid gliding ﬂagellates with ventral pseudopod-emitting grooves. Scale-free Ovulinata parva is sister to Paulinella, so imbricate silica scales can be lost. Inter- nal hollow silica skeletons evolved twice in Thecoﬁlosea (Ebriida, Phaeodaria) or were multiply lost. Protaspa replaces preoccupied ‘Protaspis’. © 2010 Elsevier GmbH. All rights reserved. Key words: 18S rDNA phylogeny; Peregrinia; Protaspa; Rhogostoma; Tremula; Ventricleftida. 1 Their complementary contributions merit equal credit 2 Corresponding author; fax +44 1865 281310 e-mail david.bass@zoo.ox.ac.uk (D. Bass). Introduction Cercozoa is a diverse, increasingly well- characterised phylum of protists (Cavalier-Smith 1998a,b) founded mainly on the basis of 18S rDNA © 2010 Elsevier GmbH. All rights reserved. doi:10.1016/j.protis.2010.10.002