Opalozoa | |
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Opalina ranarum, an opalozoan | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Stramenopiles |
Phylum: | Bigyra |
Subphylum: | Opalozoa Cavalier-Smith, 1991 stat. nov. 2006 [1] |
Infraphyla and classes [1] | |
Opalozoa is a subphylum of heterotrophic protists of the phylum Bigyra, and is the sister group to Sagenista. [2] [1] Opalozoans are non-photosynthetic heterokonts that are ancestrally phagotrophic but many times have evolved to be osmotrophic saprotrophs in the gut of vertebrate animals. [3]
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. [4]
Subphylum Proterozoa | Subphylum Opalinata | Subphylum Kinetomonada | Subphylum Hemimastigophora |
The modern taxonomy of Opalozoa, down to order level, is as follows: [1]
The cladogram below shows the internal relationships of Opalozoa. [1]
Euglenozoa are a large group of flagellate Discoba. They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. Euglenozoa are represented by four major groups, i.e., Kinetoplastea, Diplonemea, Euglenida, and Symbiontida. Euglenozoa are unicellular, mostly around 15–40 μm (0.00059–0.00157 in) in size, although some euglenids get up to 500 μm (0.020 in) long.
The Stramenopiles, also called Heterokonts, are a clade of organisms distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, and in some they have been secondarily lost. Stramenopiles represent one of the three major clades in the SAR supergroup, along with Alveolata and Rhizaria.
The alveolates are a group of protists, considered a major clade and superphylum within Eukarya. They are currently grouped with the stramenopiles and Rhizaria among the protists with tubulocristate mitochondria into the SAR supergroup.
Pedinellales (ICN) or Pedinellida (ICZN) is a group of single-celled algae found in both marine environments and freshwater.
Monadofilosa is a grouping of Cercozoa. These organisms are single-celled amoeboid protists.
Sagenista is a group of heterokonts containing the labyrinthulids and Eogyrea, a class of yet uncultured protists. Originally, it contained the Labyrinthulids and bicosoecids. The bicosoecids have been removed, and Eogyrea were added, in order to make the group monophyletic.
Ochrophytes, also known as heterokontophytes or stramenochromes, are a group of algae. They are the photosynthetic stramenopiles, a group of eukaryotes, organisms with a cell nucleus, characterized by the presence of two unequal flagella, one of which has tripartite hairs called mastigonemes. In particular, they are characterized by photosynthetic organelles or plastids enclosed by four membranes, with membrane-bound compartments called thylakoids organized in piles of three, chlorophyll a and c as their photosynthetic pigments, and additional pigments such as β-carotene and xanthophylls. Ochrophytes are one of the most diverse lineages of eukaryotes, containing ecologically important algae such as brown algae and diatoms. They are classified either as phylum Ochrophyta or Heterokontophyta, or as subphylum Ochrophytina within phylum Gyrista. Their plastids are of red algal origin.
Opalinata is a superclass of non-phagotrophic heterokonts that unites the classes Opalinea and Blastocystea, and is the sister group to Opalomonadea.
Phaeothamniophycidae is a subclass of heterokont algae. It contains two orders, Phaeothamniales and Pleurochloridellales, and consists of species separated from Chrysophyceae.
Bigyra is a phylum of microscopic eukaryotes that are found at the base of the Stramenopiles clade. It includes three well-known heterotrophic groups Bicosoecida, Opalinata and Labyrinthulomycetes, as well as several small clades initially discovered through environmental DNA samples: Nanomonadea, Placididea, Opalomonadea and Eogyrea. The classification of Bigyra has changed several times since its origin, and its monophyly remains unresolved.
The sarcomonads or class Sarcomonadea are a group of amoeboid biciliate protists in the phylum Cercozoa. They are characterized by a propensity to move through gliding on their posterior cilium or through filopodia, a lack of scales or external theca, a soft cell surface without obvious cortical filamentous or membranous skeleton, two cilia without scales or hairs, tubular mitochondrial cristae, near-spherical extrusomes, and a microbody attached to the nucleus.
The kathablepharids or katablepharids are a group of heterotrophic flagellates closely related to cryptomonads. First described by Heinrich Leonhards Skuja in 1939, kathablepharids were named after the genus Kathablepharis. This genus is corrected to Katablepharis under botanical nomenclature, but the original spelling is maintained under zoological nomenclature. They are single-celled protists with two anteriorly directed flagella, an anterior cytostome for ingesting eukaryotic prey, and a sheath that covers the cell membrane. They have extrusomes known as ejectisomes, as well as tubular mitochondrial cristae.
Platysulcus tardus is an eukaryotic microorganism that was recently discovered to be the earliest diverging lineage of the Heterokont phylogenetic tree. It is the only member of the family Platysulcidae, order Platysulcida and class Platysulcea.
Placidozoa is a recently defined non-photosynthetic lineage of Stramenopiles.
Pirsonia is a non photosynthetic genus of heterokonts. It comprises the entirety of the family Pirsoniaceae, order Pirsoniida and class Pirsonea in the subphylum Bigyromonada, phylum Gyrista.
Endohelea is a proposed clade of eukaryotes that are related to Archaeplastida and the SAR supergroup. They used to be considered heliozoans, but phylogenetically they belong to a group of microorganisms known as Cryptista.
Raphidomonadea is a class of Stramenopiles containing both photosynthetic and phagotrophic protists. The phagotrophic groups are known as Raphopoda, and comprise actinophryid heliozoa and the marine genus Commation. The photosynthetic groups are known as the raphidophyte algae. Their relationship was elucidated through phylogenetic analyses.
Corbihelia is a proposed phylum of eukaryotes.
Nanomonadea is a class of biciliate phagotrophic, non-photosynthetic free-living opalozoans, coontaining the sole order Uniciliatida. This monophyletic group previously known as clade MAST-3 is characterized by a single hairless posterior cilium and absence of an anterior cilium.
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. Members of this phylum are characterized by the presence of a helix or a double helix/ring system in the ciliary transition region.