Euglenozoa

Euglenozoa
Two Euglena
Scientific classification
Domain: Eukaryota
(unranked): Excavata
Phylum: Euglenozoa
Classes and unplaced genera

Diplonemea
Euglenoidea
Kinetoplastea
Symbiontida
Postgaardi
Calkinsia

Synonyms
  • Euglenoida Cavalier-Smith, 1978

The euglenozoa are a large group of flagellate excavates. They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. There are two main subgroups, the euglenids and kinetoplastids. Euglenozoa are unicellular, mostly around 15-40 µm in size, although some euglenids get up to 500 µm long.[2]

Structure

Most euglenozoa have two flagella, which are inserted parallel to one another in an apical or subapical pocket. In some these are associated with a cytostome or mouth, used to ingest bacteria or other small organisms. This is supported by one of three sets of microtubules that arise from the flagellar bases; the other two support the dorsal and ventral surfaces of the cell.[3]

Some other euglenozoa feed through absorption, and many euglenids possess chloroplasts and so obtain energy through photosynthesis. These chloroplasts are surrounded by three membranes and contain chlorophylls A and B, along with other pigments, so are probably derived from a captured green alga. Reproduction occurs exclusively through cell division. During mitosis, the nuclear membrane remains intact, and the spindle microtubules form inside of it.[3]

The group is characterized by the ultrastructure of the flagella. In addition to the normal supporting microtubules or axoneme, each contains a rod (called paraxonemal), which has a tubular structure in one flagellum and a latticed structure in the other. Based on this, two smaller groups have been included here: the diplonemids and Postgaardi.[4]

Classification

The euglenozoa are generally accepted as monophyletic. They are related to Percolozoa; the two share mitochondria with disk-shaped cristae, which only occurs in a few other groups.[5] Both probably belong to a larger group of eukaryotes called the excavates.[6] This grouping, though, has been challenged.[7]

Phylogeny

The phylogeny based on the work of Cavalier-Smith 2016.[8]

Taxonomy

Phylum Euglenozoa Cavalier-Smith 1981 emend. Simpson 1997[8][9] [Euglenobionta]

  • Subphylum Glycomonada Cavalier-Smith 2016
    • Class Diplonemea Cavalier-Smith 1993 emend. Simpson 1997 [Diplosonematea; Diplonemia Cavalier-Smith 1993]
      • Order Diplonemida Cavalier-Smith 1993 [Hemistasiida]
        • Family Hemistasiidae Cavalier-Smith 2016 [Entomosigmaceae]
        • Family Diplonemidae Cavalier-Smith 1993 [Rhynchopodaceae]
    • Class Kinetoplastea Honigberg 1963 emend. Margulis 1974 [Kinetoplastida Honigberg 1963; Kinetoplasta Honigberg 1963 stat. nov.]
      • Order Bordnamonadida
        • Family Bordnamonadidae Cavalier-Smith 2013
      • Order Trypanophidida
        • Family Trypanophididae Poche 1911
      • Subclass Prokinetoplastina Vickerman 2004
        • Order Prokinetoplastida Vickerman 2004
          • Family Ichthyobodonidae Isaksen et al., 2007
      • Subclass Metakinetoplastina Vickerman 2004
        • Order Neobodonida Vickerman 2004
          • Family Rhynchomonadidae Cavalier-Smith 2016
          • Family Neobodonidae Cavalier-Smith 2016
        • Order Parabodonida Vickerman 2004
          • Family Parabodonidae Cavalier-Smith 2016 [Cryptobiaceae Poche 1911; Trypanoplasmatidae Hartmann & Chagas 1910]
        • Order Bodonida Hollande 1952 emend. Vickerman 1976 [Eubodonida Vickerman 2004]
          • Family Bodonidae Bütschli 1883 [Bodonaceae]
        • Order Trypanosomatida Kent 1880 stat. n. Hollande, 1952 emend. Vickerman 2004
  • Subphylum Plicomonada Cavalier-Smith 2017
    • Infraphylum Postgaardia Cavalier-Smith 2016 stat. nov. Cavalier-Smith 2017
      • Class Postgaardea Cavalier-Smith 1998 s.s. [Symbiontida Yubuki et al., 2009]
        • Order Bihospitida Cavalier-Smith 2016
          • Family Bihospitidae Cavalier-Smith 2016
        • Order Postgaardida Cavalier-Smith 2003
          • Family Calkinsiidae Cavalier-Smith 2016
          • Family Postgaardidae Cavalier-Smith 2016
    • Infraphylum Euglenoida Bütschli 1884 emend. Senn 1900 stat. nov. Cavalier-Smith, 2017 [Euglenophyta; Euglenida Buetschli 1884; Euglenoidina Buetschli 1884]
      • Parvphylum Entosiphona Cavalier-Smith 2016 stat. nov. Cavalier-Smith 2017
        • Class Entosiphonea Cavalier-Smith 2016
          • Order Entosiphonida Cavalier-Smith 2016
            • Family Entosiphonidae Cavalier-Smith 2016
      • Parvphylum Dipilida Cavalier-Smith 2016 stat. nov. Cavalier-Smith 2017
        • Class Stavomonadea Cavalier-Smith 2016
          • Subclass Heterostavia Cavalier-Smith 2016
            • Order Heterostavida Cavalier-Smith 2016
              • Family Serpenomonadidae Cavalier-Smith 2016
          • Subclass Homostavia Cavalier-Smith 2016
            • Order Decastavida Cavalier-Smith 2016a
              • Family Decastavidae Cavalier-Smith 2016a
              • Family Keelungiidae Cavalier-Smith 2016a
            • Order Petalomonadida Cavalier-Smith 1993
              • Family Sphenomonadidae Kent 1880 [Sphenomonadales Leedale 1967; Sphenomonadina Leedale 1967]
              • Family Petalomonadidae [Petalomonadaceae Buetschli 1884; Notosolenaceae Stokes 1888; Scytomonadaceae Ritter von Stein 1878; Petalomonadea Cavalier-Smith 1993; Petalomonadophyceae]
        • Class Ploeotarea Cavalier-Smith 2016
          • Order Ploeotiida Cavalier-Smith 1993
            • Family Lentomonadidae Cavalier-Smith 2016
            • Family Ploeotiidae Cavalier-Smith 2016
        • Superclass Spirocuta Cavalier-Smith 2016
          • Class Peranemea Cavalier-Smith 1993 emend. Cavalier-Smith 2016
            • Subclass Acroglissia Cavalier-Smith 2016
              • Order Acroglissida Cavalier-Smith 2016
                • Family Teloproctidae Cavalier-Smith 2016a
            • Subclass Peranemia Cavalier-Smith 2016
              • Order Peranemida Bütschli 1884 stat. nov. Cavalier-Smith 1993
                • Family Peranematidae [Peranemataceae Dujardin 1841; Pseudoperanemataceae Christen 1962]
            • Subclass Anisonemia Cavalier-Smith 2016
              • Order Anisonemida Cavalier-Smith 2016 [Heteronematales Leedale 1967]
                • Family Anisonemidae Saville Kent, 1880 em. Cavalier-Smith 2016 [Heteronemidae; Zygoselmidaceae Kent 188]
              • Order Natomonadida Cavalier-Smith 2016
                • Suborder Metanemina Cavalier-Smith 2016
                  • Family Neometanemidae Cavalier-Smith 2016
                • Suborder Rhabdomonadina Leedale 1967 emend. Cavalier-Smith 1993 [Astasida Ehrenberg 1831; Rhabdomonadia Cavalier-Smith 1993; Rhabdomonadophyceae; Rhabdomonadales]
                  • Family Distigmidae Hollande, 1942
                  • Family Astasiidae Saville Kent, 1884 [Rhabdomonadaceae Fott 1971; Menoidiaceae Buetschli 188; Menoidiidae Hollande, 1942; Rhabdomonadidae]
          • Class Euglenophyceae Schoenichen 1925 emend. Marin & Melkonian 2003 [Euglenea Bütschli 1884 emend. Busse & Preisfeld 2002; Euglenoidea Bütschli 1884; Euglenida Bütschli 1884] (Photosynthetic clade)
            • Subclass Rapazia Cavalier-Smith 2016
              • Order Rapazida Cavalier-Smith 2016
                • Family Rapazidae Cavalier-Smith 2016
            • Subclass Euglenophycidae Busse and Preisfeld, 2003
              • Order Eutreptiida [Eutreptiales Leedale 1967 emend. Marin & Melkonian 2003; Eutreptiina Leedale 1967]
                • Family Eutreptiaceae [Eutreptiaceae Hollande 1942]
              • Order Euglenida Ritter von Stein, 1878 stat. n. Calkins, 1926 [Euglenales Engler 1898 emend. Marin & Melkonian 2003; Euglenina Buetschli 1884; Euglenomorphales Leedale 1967; Colaciales]
                • Family Euglenamorphidae Hollande, 1952 stat. n. Cavalier-Smith 2016 [Euglenomorphaceae; Hegneriaceae Brumpt & Lavier 1924]
                • Family Phacidae [Phacaceae Kim et al. 2010]
                • Family Euglenidae [Euglenaceae Dujardin 1841 emend. Kim et al. 2010] (Mucilagenous clade)

References

  1. ↑ T. Cavalier-Smith (1981). "Eukaryote Kingdoms: Seven or Nine?". BioSystems. 14 (3–4): 461–481. doi:10.1016/0303-2647(81)90050-2. PMID 7337818.
  2. ↑ "Euglenozoa". Retrieved 21 May 2013.
  3. 1 2 David J. Patterson (1999). "The Diversity of Eukaryotes". American Naturalist. 154 (S4): S96–S124. doi:10.1086/303287. PMID 10527921.
  4. ↑ Alastair G. B. Simpson (1997). "The Identity and Composition of Euglenozoa". Archiv für Protistenkunde. 148: 318–328. doi:10.1016/s0003-9365(97)80012-7.
  5. ↑ Baldauf, S. L.; Roger, A. J.; Wenk-Siefert, I.; Doolittle, W. Ford (2000). "A Kingdom-Level Phylogeny of Eukaryotes Based on Combined Protein Data". Science. 290 (5493): 972–977. doi:10.1126/science.290.5493.972. PMID 11062127.
  6. ↑ Alastair G. Simpson (2003). "Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota)". International Journal of Systematic and Evolutionary Microbiology. 53 (Pt 6): 1759–1777. doi:10.1099/ijs.0.02578-0. PMID 14657103.
  7. ↑ Cavalier-Smith T (December 2009). "Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree". Biol Lett. 6 (3): 342–5. doi:10.1098/rsbl.2009.0948. PMC 2880060. PMID 20031978.
  8. 1 2 Thomas Cavalier-Smith (2016). "Higher Classification and Phylogeny of Euglenozoa". European Journal of Protistology. 56: 250–276. doi:10.1016/j.ejop.2016.09.003. PMID 27889663.
  9. ↑ Thomas Cavalier-Smith (2017). "Euglenoid pellicle morphogenesis and evolution in light of comparative ultrastructure and trypanosomatid biology: Semi-conservative microtubule/strip duplication, strip shaping and transformation". European Journal of Protistology. 61 (A): 137–179. doi:10.1016/j.ejop.2017.09.002.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.