Phylum of eukaryotic organisms
Gyrista is a phylum of heterokont protists containing three diverse groups: the mostly photosynthetic Ochrophyta, the parasitic Pseudofungi, and the recently described group of nanoflagellates known as Bigyromonada.[2] Members of this phylum are characterized by the presence of a helix or a double helix/ring system in the ciliary transition region.[1]
Systematics
Taxonomic history
Gyrista was first described in 1998 by protistologist Thomas Cavalier-Smith in his work A revised six-kingdom system of life, originally as a superphylum containing two phyla: Ochrophyta, the heterokont algae; and Bigyra, which then contained the pseudofungi and bigyromonads together with the opalines.[1] Later, the name Bigyra was modified to contain opalines, bicosoecids and labyrinthulomycetes, while the Ochrophyta, Pseudofungi and Bigyromonada remained as groups within Gyrista.[2]
Molecular phylogenetics
Gyrista was seen in 2017 as the sister group to phylum Bigyra, which contains the Sagenista and Opalozoa. Together, Gyrista and Bigyra form the superphylum Stramenopiles or Heterokonta.[2][4]
A phylogenetic analysis in 2022 recovered a monophyletic Bigyromonada sister to Pseudofungi. The "Bigyra" is paraphyletic:[5]
Classification
The 2018 revised taxonomy of Gyrista is the following,[2] with the inclusion of new ochrophyte classes described in 2020[6] and 2021:[7]
- Subphylum Bigyromonada Cavalier-Smith 1998
- Class Developea Aleoshin et al. ex Cavalier-Smith 2017 [=Bigyromonadea Cavalier-Smith 1997]
- Class Pirsonea Cavalier-Smith 2017[2]
- Subphylum Pseudofungi Cavalier-Smith 1986 [=Heterokontimycotina M.W. Dick 1976]
- Class Hyphochytrea Cavalier-Smith 1986 [=Hyphochytriomycota Whittaker 1969]
- Class Oomycetes Winter in Rabenhorst 1879 [=Oomycota Arx 1967; Peronosporomycetes M.W. Dick 2001]
- Subphylum Ochrophytina Cavalier-Smith 1995 [=Heterokontophyta van den Hoek et al. 1978; Stramenochromes Leipe et al. 1994]
- Infraphylum Chrysista Cavalier-Smith 1991
- Superclass Limnistia Cavalier-Smith 1996 emend. 2006
- Superclass Raphidoistia Cavalier-Smith 1986 orth. mut. 2006
- Superclass Fucistia Cavalier-Smith 1995
- Class Aurophyceae Cavalier-Smith 2013
- Subclass Aurearenophycidae Kai Yoshii Nakayama & Inouye 2008 (as Aurearenophyceae)[8] stat. nov. Cavalier-Smith 2013[9]
- Subclass Phaeothamniophycidae Andersen & Bailey 1998 (as Phaeothamniophyceae) stat. nov. Cavalier-Smith 2006
- Class Chrysomerophyceae Cavalier-Smith 1995
- Class Chrysoparadoxophyceae Wetherbee et al. 2019
- Class Phaeosacciophyceae R.A.Andersen L.Graf & H.S.Yoon 2020[6]
- Class Schizocladiophyceae Henry Okuda & Kawai 2003
- Class Phaeophyceae Kjellman 1891 [=Fucophyceae Warming 1884; Melanophyceae Rabenhorst 1863]
- Class Xanthophyceae Allorge ex Fritsch 1935 [=Tribophyceae Hibberd 1981;[11] Heterokontae Luther 1899]
- Infraphylum Diatomista Derelle et al. ex Cavalier-Smith 2017
- Superclass Hypogyrista Cavalier-Smith 1995 stat. nov. 2006
- Class Dictyochophyceae Silva 1980 [=Dictyochia Haeckel 1894; Alophycidae Cavalier-Smith 2006]
- Subclass Pedinellia Cavalier-Smith 1986 stat. nov. 2017 [=Actinochrysophyceae Cavalier-Smith 1995; Axodines]
- Subclass Pelagophycidae Andersen & Saunders 1993 (as Pelagophyceae) ex Cavalier-Smith 2006
- ?Subclass Sulcophycidae Cavalier-Smith 2013 – ?Sulcochrysis[a]
- Class Pinguiophyceae Kawachi et al. 2002
- Superclass Khakista Cavalier-Smith 2000 stat. nov. 2017
- Class Bolidophyceae
- Class Diatomeae [=Bacillariophyceae]
- Subclass Corethrophycidae Round & Crawford 1990
- Subclass Rhizosoleniophycidae Round & Crawford 1990
- Subclass Eucentricophycidae Cavalier-Smith 2000
- Subclass Bacillariophycidae [=Pennatia Pennatia Schütt 1896; =Pennatophycidae]
- Ochrophytina incertae sedis