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.
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.
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.
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.
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. Both probably belong to a larger group of eukaryotes called the excavates. This grouping, though, has been challenged.
The phylogeny based on the work of Cavalier-Smith 2016.
Phylum Euglenozoa Cavalier-Smith 1981 emend. Simpson 1997 [Euglenobionta]
Subphylum Postgaardia Cavalier-Smith 2016Class Postgaardea Cavalier-Smith 1998 s.s. [Symbiontida Yubuki et al., 2009]Order Bihospitida Cavalier-Smith 2016Family Bihospitidae Cavalier-Smith 2016Order Postgaardida Cavalier-Smith 2003Family Calkinsiidae Cavalier-Smith 2016Family Postgaardidae Cavalier-Smith 2016Subphylum Glycomonada Cavalier-Smith 2016Class 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 BordnamonadidaFamily Bordnamonadidae Cavalier-Smith 2013Order TrypanophididaFamily Trypanophididae Poche 1911Subclass Prokinetoplastina Vickerman 2004Order Prokinetoplastida Vickerman 2004Family Ichthyobodonidae Isaksen et al., 2007Subclass Metakinetoplastina Vickerman 2004Order Neobodonida Vickerman 2004Family Rhynchomonadidae Cavalier-Smith 2016Family Neobodonidae Cavalier-Smith 2016Order Parabodonida Vickerman 2004Family 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 2004Family Trypanosomatidae Doflein 1901Subphylum Euglenoida Bütschli 1884 emend. Senn 1900 stat. nov. Cavalier-Smith, 1993 [Euglenophyta; Euglenida Buetschli 1884; Euglenoidina Buetschli 1884]Infraphylum Entosiphona Cavalier-Smith 2016Class Entosiphonea Cavalier-Smith 2016Order Entosiphonida Cavalier-Smith 2016Family Entosiphonidae Cavalier-Smith 2016Infraphylum Dipilida Cavalier-Smith 2016Class Stavomonadea Cavalier-Smith 2016Subclass Heterostavia Cavalier-Smith 2016Order Heterostavida Cavalier-Smith 2016Family Serpenomonadidae Cavalier-Smith 2016Subclass Homostavia Cavalier-Smith 2016Order Decastavida Cavalier-Smith 2016aFamily Decastavidae Cavalier-Smith 2016aFamily Keelungiidae Cavalier-Smith 2016aOrder Petalomonadida Cavalier-Smith 1993Family 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 2016Order Ploeotiida Cavalier-Smith 1993Family Lentomonadidae Cavalier-Smith 2016Family Ploeotiidae Cavalier-Smith 2016Superclass Spirocuta Cavalier-Smith 2016Class Peranemea Cavalier-Smith 1993 emend. Cavalier-Smith 2016Subclass Acroglissia Cavalier-Smith 2016Order Acroglissida Cavalier-Smith 2016Family Teloproctidae Cavalier-Smith 2016aSubclass Peranemia Cavalier-Smith 2016Order Peranemida Bütschli 1884 stat. nov. Cavalier-Smith 1993Family Peranematidae [Peranemataceae Dujardin 1841; Pseudoperanemataceae Christen 1962]Subclass Anisonemia Cavalier-Smith 2016Order Anisonemida Cavalier-Smith 2016 [Heteronematales Leedale 1967]Family Anisonemidae Saville Kent, 1880 em. Cavalier-Smith 2016 [Heteronemidae; Zygoselmidaceae Kent 188]Order Natomonadida Cavalier-Smith 2016Suborder Metanemina Cavalier-Smith 2016Family Neometanemidae Cavalier-Smith 2016Suborder Rhabdomonadina Leedale 1967 emend. Cavalier-Smith 1993 [Astasida Ehrenberg 1831; Rhabdomonadia Cavalier-Smith 1993; Rhabdomonadophyceae; Rhabdomonadales]Family Distigmidae Hollande, 1942Family 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 2016Order Rapazida Cavalier-Smith 2016Family Rapazidae Cavalier-Smith 2016Subclass Euglenophycidae Busse and Preisfeld, 2003Order 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)
