1887

Abstract

It is argued here that the anaerobic protozoan zooflagellate Parabasalia, and Eopharyngia (diplomonads, enteromonads, retortamonads) constitute a holophyletic group, for which the existing name Trichozoa is adopted as a new subphylum. Ancestrally, Trichozoa probably had hydrogenosomes, stacked Golgi dictyosomes, three anterior centrioles and one posterior centriole: the typical tetrakont pattern. It is also argued that the closest relatives of Trichozoa are Anaeromonada (, oxymonads), and the two groups are classified as subphyla of a revised phylum Metamonada. Returning Parabasalia and Anaeromonadea to Metamonada, as in Grassé's original classification, simplifies classification of the kingdom Protozoa by reducing the number of phyla within infrakingdom Excavata from five to four. Percolozoa (Heterolobosea plus Percolatea classis nov.) and Metamonada are probably both ancestrally quadriciliate with a kinetid of four centrioles attached to the nucleus; the few biciliates among them are probably secondarily derived. Metamonada ancestrally probably had two divergent centriole pairs, whereas, in Percolozoa, all four centrioles are parallel. It is suggested that Discicristata (Percolozoa, Euglenozoa) are holophyletic, ancestrally with two parallel centrioles. In the phylum Loukozoa, Malawimonadea classis nov. is established for (with a new family and order also) and Diphyllatea classis nov., for Diphylleida (, ), is transferred back to Apusozoa. A new class, order and family are established for the anaerobic, biciliate, tricentriolar , transferring it from Loukozoa to Trichozoa because of its triply flanged cilia; like , it may be secondarily biciliate – its unique combination of putative hydrogenosomes and flanged cilia agree with molecular evidence that is sister to Eopharyngia, diverging before their ancestor lost hydrogenosomes and acquired a cytopharynx. Removal of anaeromonads and makes Loukozoa more homogeneous, being basically biciliate, aerobic and free-living, in contrast to Metamonada. A new taxon-rich rRNA tree supports holophyly of Discicristata and Trichozoa strongly, holophyly of Metamonada and Excavata and paraphyly of Loukozoa weakly. Mitochondria were probably transformed into hydrogenosomes independently in the ancestors of lyromonad Percolozoa and Metamonada and further reduced in the ancestral eopharyngian. Evidence is briefly discussed that Metamonada and all other excavates share a photosynthetic ancestry with Euglenozoa and are secondarily non-photosynthetic, as predicted by the cabozoan hypothesis for a single secondary symbiogenetic acquisition of green algal plastids by the last common ancestor of Euglenozoa and Cercozoa. Excavata plus core Rhizaria (Cercozoa, Retaria) probably form an ancestrally photophagotrophic clade. The origin from a benthic loukozoan ancestor of the characteristic cellular features of Percolozoa and Euglenozoa through divergent adaptations for feeding on or close to surfaces is also discussed.

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2019-08-19
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References

  1. Andersson, J. O. & Roger, A. J. ( 2002; ). A cyanobacterial gene in nonphotosynthetic protists – an early chloroplast acquisition in eukaryotes? Curr Biol 12, 115–119.
    [Google Scholar]
  2. Archibald, J. M., O'Kelly, C. J. & Doolittle, W. F. ( 2002; ). The chaperonin genes of jakobid and jakobid-like flagellates: implications for eukaryotic evolution. Mol Biol Evol 19, 422–431.[CrossRef]
    [Google Scholar]
  3. Baldauf, S. L., Roger, A. J., Wenk-Siefert, I. & Doolittle, W. F. ( 2000; ). A kingdom-level phylogeny of eukaryotes based on combined protein data. Science 290, 972–977.[CrossRef]
    [Google Scholar]
  4. Bapteste, E., Brinkmann, H., Lee, J. A. & 8 other authors ( 2002; ). The analysis of 100 genes supports the grouping of three highly divergent amoebae: Dictyostelium, Entamoeba, and Mastigamoeba. Proc Natl Acad Sci U S A 99, 1414–1419.[CrossRef]
    [Google Scholar]
  5. Bernard, C., Simpson, A. G. B. & Patterson, D. J. ( 1997; ). An ultrastructural study of a free-living retortamonad, Chilomastix cuspidata (Larsen & Patterson, 1990) n. comb. (Retortamonadida, Protista). Eur J Protistol 33, 254–265.[CrossRef]
    [Google Scholar]
  6. Bolivar, I., Fahrni, J. F., Smirnov, A. & Pawlowski, J. ( 2001; ). SSU rRNA-based phylogenetic position of the genera Amoeba and Chaos (Lobosea, Gymnamoebia): the origin of gymnamoebae revisited. Mol Biol Evol 18, 2306–2314.[CrossRef]
    [Google Scholar]
  7. Brugerolle, G. & Müller, M. ( 2000; ). Amitochondriate flagellates. In The Flagellates, pp. 166–189. Edited by J. R. Green & B. S. C. Leadbeater. London: Taylor & Francis.
  8. Brugerolle, G. & Patterson, D. J. ( 1997; ). Ultrastructure of Trimastix convexa Hollande, an amitochondriate anaerobic flagellate with a previously undescribed organization. Eur J Protistol 33, 121–130.[CrossRef]
    [Google Scholar]
  9. Brugerolle, G., Bricheux, G., Philippe, H. & Coffe, G. ( 2002; ). Collodictyon triciliatum and Diphylleia rotans (=Aulacomonas submarina) form a new family of flagellates (Collodictyonidae) with tubular mitochondrial cristae that is phylogenetically distant from other flagellate groups. Protist 153, 59–70.[CrossRef]
    [Google Scholar]
  10. Busse, I. & Preisfeld, A. ( 2002; ). Phylogenetic position of Rhynchopus sp. and Diplonema ambulator as indicated by analyses of euglenozoan small subunit ribosomal DNA. Gene 284, 83–91.[CrossRef]
    [Google Scholar]
  11. Cavalier-Smith, T. ( 1980; ). Cell compartmentation and the origin of eukaryote membranous organelles. In Endocytobiology: Endosymbiosis and Cell Biology, a Synthesis of Recent Research, pp. 893–916. Edited by W. Schwemmler & H. E. A. Schenk. Berlin: de Gruyter.
  12. Cavalier-Smith, T. ( 1981; ). Eukaryote kingdoms: seven or nine? Biosystems 14, 461–481.[CrossRef]
    [Google Scholar]
  13. Cavalier-Smith, T. ( 1982; ). The evolutionary origin and phylogeny of eukaryote flagella. In Prokaryotic and Eukaryotic Flagella: 35th Symposium of the Society of Experimental Biology, pp. 465–493. Edited by W. B. Amos & J. G. Duckett. Cambridge: Cambridge University Press.
  14. Cavalier-Smith, T. ( 1983; ). A 6-kingdom classification and a unified phylogeny. In Endocytobiology II, pp. 1027–1034. Edited by W. Schwemmler & H. E. A. Schenk. Berlin: de Gruyter.
  15. Cavalier-Smith, T. ( 1987a; ). The origin of eukaryotic and archaebacterial cells. Ann N Y Acad Sci 503, 17–54.[CrossRef]
    [Google Scholar]
  16. Cavalier-Smith, T. ( 1987b; ). The simultaneous symbiotic origin of mitochondria, chloroplasts, and microbodies. Ann N Y Acad Sci 503, 55–71.[CrossRef]
    [Google Scholar]
  17. Cavalier-Smith, T. ( 1987c; ). The origin of Fungi and pseudofungi. In Evolutionary Biology of the Fungi, Symposium of the British Mycological Society no. 13, pp. 339–353. Edited by A. D. M. Rayner, C. M. Brasier & D. Moore. Cambridge: Cambridge University Press.
  18. Cavalier-Smith, T. ( 1989; ). Systems of kingdoms. In McGraw-Hill Yearbook of Science and Technology 1989, pp. 175–179. Edited by S. P. Parker. New York: McGraw-Hill.
  19. Cavalier-Smith, T. ( 1991; ). Cell diversification in heterotrophic flagellates. In The Biology of Free-Living Heterotrophic Flagellates, pp. 113–131. Edited by D. J. Patterson & J. Larsen. Oxford: Clarendon Press.
  20. Cavalier-Smith, T. ( 1992; ). Origin of the cytoskeleton. In The Origin and Evolution of the Cell, pp. 79–106. Edited by H. Hartman & K. Matsuno. Singapore: World Scientific Publishers.
  21. Cavalier-Smith, T. ( 1993a; ). Kingdom Protozoa and its 18 phyla. Microbiol Rev 57, 953–994.
    [Google Scholar]
  22. Cavalier-Smith, T. ( 1993b; ). Percolozoa and the symbiotic origin of the metakaryote cell. In Endocytobiology V, pp. 399–406. Edited by H. Ishikawa, M. Ishida & S. Sato. Tübingen: Tübingen University Press.
  23. Cavalier-Smith, T. ( 1997; ). Amoeboflagellates and mitochondrial cristae in eukaryotic evolution: megasystematics of the new protozoan subkingdoms Eozoa and Neozoa. Arch Protistenkd 147, 237–258.[CrossRef]
    [Google Scholar]
  24. Cavalier-Smith, T. ( 1998; ). A revised six-kingdom system of life. Biol Rev Camb Philos Soc 73, 203–266.[CrossRef]
    [Google Scholar]
  25. Cavalier-Smith, T. ( 1999; ). Principles of protein and lipid targeting in secondary symbiogenesis: euglenoid, dinoflagellate, and sporozoan plastid origins and the eukaryote family tree. J Eukaryot Microbiol 46, 347–366.[CrossRef]
    [Google Scholar]
  26. Cavalier-Smith, T. ( 2000; ). Flagellate megaevolution: the basis for eukaryote diversification. In The Flagellates, pp. 361–390. Edited by J. R. Green & B. S. C. Leadbeater. London: Taylor & Francis.
  27. Cavalier-Smith, T. ( 2002a; ). The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification. Int J Syst Evol Microbiol 52, 7–76.
    [Google Scholar]
  28. Cavalier-Smith, T. ( 2002b; ). The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa. Int J Syst Evol Microbiol 52, 297–354.
    [Google Scholar]
  29. Cavalier-Smith, T. ( 2002c; ). Chloroplast evolution: secondary symbiogenesis and multiple losses. Curr Biol 12, R62–R64.[CrossRef]
    [Google Scholar]
  30. Cavalier-Smith, T. ( 2003; ). Genome reduction and evolution of novel genetic membranes and protein-targeting machinery in eukaryote-eukaryote chimaeras (meta-algae). Philos Trans R Soc Lond B Biol Sci 358, 109–133.[CrossRef]
    [Google Scholar]
  31. Cavalier-Smith, T. & Chao, E. E. ( 1996; ). Molecular phylogeny of the free-living archezoan Trepomonas agilis and the nature of the first eukaryote. J Mol Evol 43, 551–562.[CrossRef]
    [Google Scholar]
  32. Cavalier-Smith, T. & Chao, E. E.-Y. ( 2003a; ). Molecular phylogeny of centrohelid heliozoa, a novel lineage of bikont eukaryotes that arose by ciliary loss. J Mol Evol 56, 387–396.[CrossRef]
    [Google Scholar]
  33. Cavalier-Smith, T. & Chao, E. E.-Y. ( 2003b; ). Phylogeny of Choanozoa, Apusozoa, and other protozoa and early eukaryote megaevolution. J Mol Evol 56, 540–563.[CrossRef]
    [Google Scholar]
  34. Cavalier-Smith, T. & Chao, E. E.-Y. ( 2003c; ). Phylogeny and classification of phylum Cercozoa (Protozoa). Protist 154, 341–358.[CrossRef]
    [Google Scholar]
  35. Chatton, E. ( 1925; ). Pansporella perplexa, réflexions sur la biologie et la phylogenèse des Protozoaires. Ann Sci Nat Biol Anim Zool (10e sér) 8, 6–84 (in French).
    [Google Scholar]
  36. Chatton, E. ( 1937; ). Gregarella fabrearum Chatt. et Brach., protiste parasite du cilié Fabrea salina. Arch Zoo Exp Géné 78, 216–237 (in French).
    [Google Scholar]
  37. Corliss, J. O. ( 1985; ). The kingdom Protista and its 45 phyla. Biosystems 17, 87–126.
    [Google Scholar]
  38. Corliss, J. O. ( 1994; ). An interim utilitarian (“user friendly”) hierarchical classification and characterisation of the protists. Acta Protozool 33, 1–51.
    [Google Scholar]
  39. Corsetti, F. A., Awramik, S. M. & Pierce, D. ( 2003; ). A complex microbiota from snowball Earth times: microfossils from the Neoproterozoic Kingston Peak Formation, Death Valley, USA. Proc Natl Acad Sci U S A 100, 4399–4404.[CrossRef]
    [Google Scholar]
  40. Dacks, J. & Roger, A. J. ( 1999; ). The first sexual lineage and the relevance of facultative sex. J Mol Evol 48, 779–783.[CrossRef]
    [Google Scholar]
  41. Dacks, J. B., Silberman, J. D., Simpson, A. G. B., Moriya, S., Kudo, T., Ohkuma, M. & Redfield, R. J. ( 2001; ). Oxymonads are closely related to the excavate taxon Trimastix. Mol Biol Evol 18, 1034–1044.[CrossRef]
    [Google Scholar]
  42. Delwiche, C. F. ( 1999; ). Tracing the thread of plastid diversity through the tapestry of life. Am Nat 154 (Suppl. 4), S164–S177.[CrossRef]
    [Google Scholar]
  43. Diesing, K. M. ( 1865; ). Revision der Prothelminthen. Sitzungsber K Akad Wiss Wien, 1ii. Vienna: Vienna Academy of Sciences.
  44. Diesing, K. M. ( 1866; ). Revision der Prothelminthen. Sitzungsber K Akad Wiss Wien, 1iii. Vienna: Vienna Academy of Sciences.
  45. Dyall, S. D. & Johnson, P. J. ( 2000; ). Origins of hydrogenosomes and mitochondria: evolution and organelle biogenesis. Curr Opin Microbiol 3, 404–411.[CrossRef]
    [Google Scholar]
  46. Edgcomb, V., Viscogliosi, E., Simpson, A. G. B., Delgado-Viscogliosi, P., Roger, A. J. & Sogin, M. L. ( 1998; ). New insights into the phylogeny of trichomonads inferred from small subunit rRNA sequences. Protist 149, 359–366.[CrossRef]
    [Google Scholar]
  47. Edgcomb, V. P., Roger, A. J., Simpson, A. G. B., Kysela, D. T. & Sogin, M. L. ( 2001; ). Evolutionary relationships among “jakobid” flagellates as indicated by alpha- and beta-tubulin phylogenies. Mol Biol Evol 18, 514–522.[CrossRef]
    [Google Scholar]
  48. Embley, T. M. & Hirt, R. P. ( 1998; ). Early branching eukaryotes? Curr Opin Genet Dev 8, 624–629.[CrossRef]
    [Google Scholar]
  49. Farmer, M. A. ( 1993; ). Ultrastructure of Ditrichomonas honigbergii n. g., n. sp. (Parabasalia) and its relationship to amitochondrial protists. J Eukaryot Microbiol 40, 619–626.[CrossRef]
    [Google Scholar]
  50. Felsenstein, J. ( 1978; ). Cases in which parsimony or compatibility methods will be positively misleading. Syst Zool 27, 401–410.[CrossRef]
    [Google Scholar]
  51. Fenchel, T. & Patterson, D. J. ( 1986; ). Percolomonas cosmopolitanus (Ruinen) n. gen., a new type of filter feeding flagellate from marine plankton. J Mar Biol Assoc U K 66, 465–482.[CrossRef]
    [Google Scholar]
  52. Fenchel, T., Bernard, C., Esteban, G., Finlay, B. J., Hansen, P. J. & Iversen, N. ( 1995; ). Microbial diversity and activity in a Danish fjord with anoxic deep water. Ophelia 43, 45–100.[CrossRef]
    [Google Scholar]
  53. Flavin, M. & Nerad, T. A. ( 1993; ). Reclinomonas americana n. g., n. sp., a new freshwater heterotrophic flagellate. J Eukaryot Microbiol 40, 172–179.[CrossRef]
    [Google Scholar]
  54. Gaunt, M. W. & Miles, M. A. ( 2002; ). An insect molecular clock dates the origin of the insects and accords with palaeontological and biogeographic landmarks. Mol Biol Evol 19, 748–761.[CrossRef]
    [Google Scholar]
  55. Gerbod, D., Edgcomb, V. P., Noel, C., Zenner, L., Wintjens, R., Delgado-Viscogliosi, P., Holder, M. E., Sogin, M. L. & Viscogliosi, E. ( 2001; ). Phylogenetic position of the trichomonad parasite of turkeys, Histomonas meleagridis (Smith) Tyzzer, inferred from small subunit rRNA sequence. J Eukaryot Microbiol 48, 498–504.[CrossRef]
    [Google Scholar]
  56. Gibbs, S. P. ( 1978; ). The chloroplasts of Euglena may have evolved from symbiotic green algae. Can J Bot 56, 2883–2889.[CrossRef]
    [Google Scholar]
  57. Grassé, P.-P. ( 1952; ). Classe des zooflagellés: Zooflagellata ou Zoomastigina (Euflagellata Claus 1887). Géneralités. In Traité de Zoologie, vol. 1, fasc. 1, pp. 574–578. Edited by P.-P. Grassé. Paris: Masson (in French).
  58. Henze, K., Horner, D. S., Suguri, S., Moore, D. V., Sanchez, L. B., Müller, M. & Embley, T. M. ( 2001; ). Unique phylogenetic relationships of glucokinase and glucosephosphate isomerase of the amitochondriate eukaryotes Giardia intestinalis, Spironucleus barkhanus and Trichomonas vaginalis. Gene 281, 123–131.[CrossRef]
    [Google Scholar]
  59. Hoffman, P. F., Kaufman, A. J., Halverson, G. P. & Schrag, D. P. ( 1998; ). A Neoproterozoic snowball earth. Science 281, 1342–1346.[CrossRef]
    [Google Scholar]
  60. Honigberg, B. M. ( 1973; ). Remarks upon trichomonad affinities of certain parasitic protozoa. In Progress in Protozoology: Abstracts of Papers Read at the 4th International Congress of Protozoology, Clermont-Ferrand, 2–10 September 1973, p. 187. Edited by P. De Puytorac & J. Grain. Clermont-Ferrand: Université de Clermont.
  61. Honigberg, B. M., Balamuth, W., Bovee, E. C. & 8 other authors ( 1964; ). A revised classification of phylum Protozoa. J Protozool 11, 7–20.[CrossRef]
    [Google Scholar]
  62. Horner, D. S. & Embley, T. M. ( 2001; ). Chaperonin 60 phylogeny provides further evidence for secondary loss of mitochondria among putative early-branching eukaryotes. Mol Biol Evol 18, 1970–1975.[CrossRef]
    [Google Scholar]
  63. Ishida, K., Green, B. R. & Cavalier-Smith, T. ( 1999; ). Diversification of a chimaeric algal group, the chlorarachniophytes: phylogeny of nuclear and nucleomorph small-subunit rRNA genes. Mol Biol Evol 16, 321–331.[CrossRef]
    [Google Scholar]
  64. Keeling, P. J. & Doolittle, W. F. ( 1997; ). Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin. Proc Natl Acad Sci U S A 94, 1270–1275.[CrossRef]
    [Google Scholar]
  65. Kirby, H. ( 1947; ). Flagellates and host relationships of trichomonad flagellates. J Parasitol 33, 214–228.[CrossRef]
    [Google Scholar]
  66. Knoll, A. H. ( 2000; ). Learning to tell Neoproterozoic time. Precambrian Res 100, 3–20.[CrossRef]
    [Google Scholar]
  67. Lang, B. F., O'Kelly, C., Nerad, T., Gray, M. W. & Burger, G. ( 2002; ). The closest unicellular relatives of animals. Curr Biol 12, 1773–1778.[CrossRef]
    [Google Scholar]
  68. Leipe, D. D., Gunderson, J. H., Nerad, T. A. & Sogin, M. L. ( 1993; ). Small subunit ribosomal RNA of Hexamita inflata and the quest for the first branch in the eukaryotic tree. Mol Biochem Parasitol 59, 41–48.[CrossRef]
    [Google Scholar]
  69. Levine, N. D., Corliss, J. O., & Cox, F. E. & 13 other authors ( 1980; ). A newly revised classification of the protozoa. J Protozool 27, 37–58.[CrossRef]
    [Google Scholar]
  70. Moestrup, Ø. ( 2000; ). The flagellate cytoskeleton. In The Flagellates: Unity, Diversity and Evolution, pp. 69–94. The Systematics Association Special Volume Series 59. Edited by B. S. C. Leadbeater & J. C. Green. London: Taylor & Francis.
  71. Moriya, S., Dacks, J. B., Takagi, A., Noda, S., Ohkuma, M., Doolittle, W. F. & Kudo, T. ( 2003; ). Molecular phylogeny of three oxymonad genera: Pyrsonympha, Dinenympha and Oxymonas. J Eukaryot Microbiol 50, 190–197.[CrossRef]
    [Google Scholar]
  72. Morrison, H. G., Roger, A. J., Nystul, T. G., Gillin, F. D. & Sogin, M. L. ( 2001; ). Giardia lamblia expresses a proteobacterial-like DnaK homolog. Mol Biol Evol 18, 530–541.[CrossRef]
    [Google Scholar]
  73. O'Kelly, C. ( 1993; ). The jakobid flagellates: structural features of Jakoba, Reclinomonas and Histiona and implications for the early diversification of eukaryotes. J Eukaryot Microbiol 40, 627–636.[CrossRef]
    [Google Scholar]
  74. O'Kelly, C. J. & Nerad, T. A. ( 1999; ). Malawimonas jakobiformis n. gen., n. sp. (Malawimonadidae fam. nov.): a Jakoba-like heterotrophic nanoflagellate with discoidal mitochondrial cristae. J Eukaryot Microbiol 46, 522–531.[CrossRef]
    [Google Scholar]
  75. O'Kelly, C. J., Farmer, M. A. & Nerad, T. A. ( 1999; ). Ultrastructure of Trimastix pyriformis (Klebs) Bernard et al.: similarities of Trimastix species with retortamonad and jakobid flagellates. Protist 150, 149–162.[CrossRef]
    [Google Scholar]
  76. Page, F. C. & Blanton, R. L. ( 1985; ). The Heterolobosea (Sarcodina: Rhizopoda), a new class uniting the Schizopyrenida and the Acrasidae (Acrasida). Protistologica 21, 121–132.
    [Google Scholar]
  77. Patterson, D. J. ( 1988; ). The evolution of protozoa. Mem Inst Oswaldo Cruz 83 (Suppl. 1), 580–600.[CrossRef]
    [Google Scholar]
  78. Patterson, D. J. ( 1999; ). The diversity of eukaryotes. Am Nat 154 (Suppl. 4), S96–S124.[CrossRef]
    [Google Scholar]
  79. Philippe, H. & Adoutte, A. ( 1996; ). How reliable is our current view of eukaryotic phylogeny? In Protistological Actualities, pp. 17–33. Edited by G. Brugerolle & J.-P. Mignot. Clermont-Ferrand: Université Blaise Pascal de Clermont Ferrand.
  80. Philippe, H. & Adoutte, A. ( 1998; ). The molecular phylogeny of Eukaryota: solid facts and uncertainties. In Evolutionary Relationships Among Protozoa, pp. 25–56. Edited by G. H. Coombs, K. Vickerman, M. A. Sleigh & A. Warren. London: Kluwer.
  81. Philippe, H., Lopez, P., Brinkmann, H., Budin, K., Germot, A., Laurent, J., Moreira, D., Muller, M. & Le Guyader, H. ( 2000; ). Early-branching or fast-evolving eukaryotes? An answer based on slowly evolving positions. Proc R Soc Lond B Biol Sci 267, 1213–1221.[CrossRef]
    [Google Scholar]
  82. Roger, A. J. ( 1999; ). Reconstructing early events in eukaryotic evolution. Am Nat 154 (Suppl. 4), S146–S163.[CrossRef]
    [Google Scholar]
  83. Roger, A. J., Svard, S. G., Tovar, J., Graham Clark, C., Smith, M. W., Gillin, F. D. & Sogin, M. L. ( 1998; ). A mitochondrial-like chaperonin 60 gene in Giardia lamblia: evidence that diplomonads once harbored an endosymbiont related to the progenitor of mitochondria. Proc Natl Acad Sci U S A 95, 229–234.[CrossRef]
    [Google Scholar]
  84. Silberman, J. D., Simpson, A. G. B., Kulda, J., Cepicka, I., Hampl, V., Johnson, P. J. & Roger, A. J. ( 2002; ). Retortamonad flagellates are closely related to diplomonads – implications for the history of mitochondrial function in eukaryote evolution. Mol Biol Evol 19, 777–786.[CrossRef]
    [Google Scholar]
  85. Simpson, A. G. B. ( 1997; ). The identity and composition of the Euglenozoa. Arch Protistenkd 148, 318–328.[CrossRef]
    [Google Scholar]
  86. Simpson, A. G. B. & Patterson, D. J. ( 1999; ). The ultrastructure of Carpediemonas membranifera (Eukaryota) with reference to the “excavate hypothesis”. Eur J Protistol 35, 353–370.[CrossRef]
    [Google Scholar]
  87. Simpson, A. G. B. & Patterson, D. J. ( 2001; ). On core jakobids and excavate taxa: the ultrastructure of Jakoba incarcerata. J Eukaryot Microbiol 48, 480–492.[CrossRef]
    [Google Scholar]
  88. Simpson, A. G. B., Bernard, C. & Patterson, D. J. ( 2000; ). The ultrastructure of Trimastix marina Kent, 1880 (Eukaryota), an excavate flagellate. Eur J Protistol 36, 229–251.[CrossRef]
    [Google Scholar]
  89. Simpson, A. G. B., Roger, A. J., Silberman, J. D., Leipe, D. D., Edgcomb, V. P., Jermiin, L. S., Patterson, D. J. & Sogin, M. L. ( 2002a; ). Evolutionary history of “early-diverging” eukaryotes: the excavate taxon Carpediemonas is a close relative of Giardia. Mol Biol Evol 19, 1782–1791.[CrossRef]
    [Google Scholar]
  90. Simpson, A. G. B., Radek, R., Dacks, J. B. & O'Kelly, C. J. ( 2002b; ). How oxymonads lost their groove: an ultrastructural comparison of Monocercomonoides and excavate taxa. J Eukaryot Microbiol 49, 239–248.[CrossRef]
    [Google Scholar]
  91. Sleigh, M. A. & Patterson, D. J. ( 1984; ). Protozoa. In A Synoptic Classification of Living Organisms. Edited by R. S. K. Barnes. Oxford: Blackwell Scientific.
  92. Stechmann, A. & Cavalier-Smith, T. ( 2002; ). Rooting the eukaryote tree by using a derived gene fusion. Science 297, 89–91.[CrossRef]
    [Google Scholar]
  93. Stechmann, A. & Cavalier-Smith, T. ( 2003a; ). Phylogenetic analysis of eukaryotes using heat-shock protein Hsp90. J Mol Evol 57, 408–419.[CrossRef]
    [Google Scholar]
  94. Stechmann, A. & Cavalier-Smith, T. ( 2003b; ). The root of the eukaryote tree pinpointed. Curr Biol 13, R665–R666.[CrossRef]
    [Google Scholar]
  95. Tachezy, J., Sanchez, L. B. & Müller, M. ( 2001; ). Mitochondrial type iron-sulfur cluster assembly in the amitochondriate eukaryotes Trichomonas vaginalis and Giardia intestinalis, as indicated by the phylogeny of IscS. Mol Biol Evol 18, 1919–1928.[CrossRef]
    [Google Scholar]
  96. Triemer, R. E. & Farmer, M. A. ( 1991; ). The ultrastructural organization of heterotrophic euglenids and its evolutionary implications. In The Biology of Free-Living Heterotrophic Flagellates, pp. 185–204. Edited by D. J. Patterson & J. Larsen. Oxford: Clarendon Press.
  97. van der Giezen, M., Slotboom, D. J., Horner, D. S., Dyal, P. L., Harding, M., Xue, G. P., Embley, T. M. & Kunji, E. R. ( 2002; ). Conserved properties of hydrogenosomal and mitochondrial ADP/ATP carriers: a common origin for both organelles. EMBO J 21, 572–579.[CrossRef]
    [Google Scholar]
  98. Walne, P. L. & Kivic, P. A. ( 1990; ). Phylum Euglenida. In Handbook of Protoctista, pp. 270–287. Edited by L. Margulis, J. O. Corliss, M. Melkonian & D. Chapman, Boston: Jones & Bartlett.
  99. Wolfe, M., Buchheim, M., Hegewald, E., Krienitz, L. & Hepperle, D. ( 2002; ). Phylogenetic position of the Sphaeropleaceae (Chlorophyta). Plant Syst Evol 230, 161–171.[CrossRef]
    [Google Scholar]
  100. Wu, G., Henze, K. & Müller, M. ( 2001; ). Evolutionary relationships of the glucokinase from the amitochondriate protist, Trichomonas vaginalis. Gene 264, 265–271.[CrossRef]
    [Google Scholar]
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