# Opalozoa

Opalozoa is a subphylum of heterotrophic protists of the phylum Bigyra, and is the sister group to Sagenista. Opalozoans are non-photosynthetic heterokonts that are ancestrally phagotrophic but many times have evolved to be osmotrophic saprotrophs in the gut of vertebrate animals.

## Taxonomy
### History: phylum Opalozoa

In 1993 the name “Opalozoa” referred to a group of protists that was very different from what it is now. It was a phylum composed of many unrelated zooflagellates, grouped together because of the common presence of tubular mitochondrial cristae and the lack of cortical alveoli or rigid tubular ciliary hairs (retronemes). It also included the opalinids, proteomyxids and plasmodiophorids.
Cavalier-Smith's defunct phylum Opalozoa (1993) :
| Subphylum Proterozoa  Class Heteromitea  Subclass Sarcomonadia  Superorder Jakobidea  Order Jakobida  Order Cercomonadida  Superorder Thaumatomonadidea  Order Thaumatomonadida  Superorder Proteomyxidea  Order Pseudosporida  Order Leucodictyida  Subclass Thecomonadia  Order Apusomonadida  Order Cryomonadida  Subclass Anisomonadia  Order Diphylleida  Order Proteromonadida  Class Phytomyxea  Order Phagomyxida  Order Plasmodiophorida  Class Telonemea  Order Telonemida  Order Nephromycida  Class Cyathobodonea  Order Pseudodendromonadida  Order Spongomonadida  Order Kathablepharida  Class Ebridea  Order Ebriida | Subphylum Opalinata  Class Opalinea  Order Karotomorphida  Order Opalinida | Subphylum Kinetomonada  Class Kinetomonadea  Order Histionida  Order Heliomonadida | Subphylum Hemimastigophora  Class Hemimastigea  Order Hemimastigida |

### Modern classification

The modern taxonomy of Opalozoa, down to order level, is as follows:
* Subphylum Opalozoa Cavalier-Smith, 1991 stat. nov. 2006 emend. 2018
** Infraphylum Bikosia Cavalier-Smith, 2013
*** Class Bikosea Cavalier-Smith nom. n. pro Bicosoecea Cavalier-Smith, 1986
**** Subclass Bicosidia Cavalier-Smith, 2006 orth. emend.
***** Superorder Cyathobodoniae Cavalier-Smith, 1993 emend. stat. nov. 2006
****** Order Bicoecida Grassé, 1926
****** Order Anoecida Cavalier-Smith, 1997 emend. 2006
****** Order Pseudodendromonadida Hibberd, 1985 emend. Cavalier-Smith, 2006
***** Superorder Borokiae Cavalier-Smith, 2006
****** Order Borokida Cavalier-Smith, 2006
**** Subclass Rictidia Cavalier-Smith, 2013
***** Order Rictida Cavalier-Smith, 2013
** Infraphylum Placidozoa Cavalier-Smith, 2013
*** Superclass Wobblata Cavalier-Smith, 2006 stat. nov. 2013 [paraphyletic]
**** Class Placididea Moriya, Nakayama & Inouye, 2002
***** Order Placidida Moriya, Nakayama & Inouye, 2002 [=Placidae Cavalier-Smith, 2006]
**** Class Nanomonadea Cavalier-Smith, 2013
***** Order Uniciliatida Cavalier-Smith, 2013
**** Class Opalomonadea Cavalier-Smith, 2013
*** Superclass Opalinata Wenyon, 1926 emend. Cavalier-Smith, 1996 stat. nov. 2006
**** Class Opalinea Wenyon, 1926 stat. nov. Cavalier-Smith, 1993 emend. 2013
***** Order Proteromonadida Grassé, 1952 emend. Cavalier-Smith, 1993
***** Order Opalinida Poche, 1913 stat. nov. Hall, 1953 emend. Cavalier-Smith
**** Class Blastocystea Zierdt et al., 1967
***** Order Blastocystida Zierdt, 1978
* Opalozoa incertae sedis:
** Pendulomonas Tong, 1977
** Bordnamonadidae Cavalier-Smith, 2013

## Phylogeny

The cladogram below shows the internal relationships of Opalozoa.