clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
, or Ichthyosporea) are a small group of
Opisthokont
The opisthokonts () are a broad group of eukaryotes, including both the animal and fungus kingdoms. The opisthokonts, previously called the "Fungi/Metazoa group", are generally recognized as a clade. Opisthokonts together with Apusomonadida and ...
a in
Eukaryota
Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the ...
(formerly
protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exc ...
s), mostly
parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s of fish and other animals.
Significance
They are not particularly distinctive morphologically, appearing in host tissues as enlarged spheres or ovals containing
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
s, and most were originally classified in various groups as fungi, protozoa, or colorless algae. However, they form a coherent group on molecular trees, closely related to both
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s and
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
and so of interest to biologists studying their origins. In a 2008 study they emerge robustly as the sibling-group of the
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
Filozoa
The Filozoa are a monophyletic grouping within the Opisthokonta. They include animals and their nearest unicellular relatives (those organisms which are more closely related to animals than to fungi or Mesomycetozoa).
Three groups are curre ...
, which includes the animals.
Huldtgren et al., following x-ray tomography of
microfossil
A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size, the visual study of which requires the use of light or electron microscopy. A fossil which can be studied with the naked eye or low-powered magnification, ...
Doushantuo Formation
The Doushantuo Formation (formerly transcribed as Toushantuo or Toushantou, from ) is a geological formation in western Hubei, eastern Guizhou, southern Shaanxi, central Jiangxi, and other localities in China. It is known for the fossil Lagerst ...
, has interpreted them as mesomycetozoan spore capsules.
Terminology
The name DRIP is an acronym for the first protozoa identified as members of the group,
Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford.
His research has led to disc ...
later treated them as the class Ichthyosporea, since they were all parasites of fish.
* order
Dermocystida
Dermocystida is an order of parasitic eukaryotes.
Taxonomy
* Family Rhinosporidiaceae Mendoza et al. 2001
** Genus '' Amphibiocystidium'' Pascolini et al. 2003
** Genus '' Chromosphaera'' Grau-Bové et al. 2017
** Genus '' Dermocystidium'' Pé ...
** "D": ''
Dermocystidium
''Dermocystidium'' is a genus of cyst-forming, parasitic eukaryotes of fish, which are the causative agents of dermocystidiosis.
Taxonomic History
The genus ''Dermocystidium'' was described in 1907. It was previously thought to be a genus of fu ...
''. One species, ''
Rhinosporidium seeberi
''Rhinosporidium seeberi'' is a eukaryotic pathogen responsible for rhinosporidiosis, a disease which affects humans, horses, dogs, and to a lesser extent cattle, cats, foxes, and birds. It is most commonly found in tropical areas, especially I ...
'', infects birds and mammals, including humans.
** "R": the "rosette agent", now known as ''
Sphaerothecum destruens
''Sphaerothecum destruens'' (the rosette agent) is a parasite of fish. It was first discovered in the United States in association with invasive species including topmouth gudgeon, but was found to be the causative agent of a disease in the UK ...
''
* order
Ichthyophonida
Ichthyophonida is an order of parasitic eukaryotes.
Taxonomy
Members of Ichthyophonida include:
* Amoebidiaceae
**'' Amoebidium''
***'' Amoebidium appalachense''
***'' Amoebidium parasiticum''
* Paramoebidiidae
**'' Paramoebidium''
***'' P ...
** "I": ''
Ichthyophonus
''Ichthyophonus'' is a genus of unicellular eukaryotic parasites of fish. They were once considered to be fungi, but phylogenetic evidence suggests they are protists related to both fungi and animal
Animals are multicellular, eukaryotic ...
''
** "P": ''
Psorospermium
''Psorospermium haeckeli'' (or ''Psorospermium haeckelii'') is a parasitic species.
References
Parasitic opisthokonts
Mesomycetozoea
{{Holozoa-stub ...
''
Since other new members have been added (e.g. the former fungal orders
Eccrinales
Eccrinales are an order of eukaryotes, previously thought to be zygomycete fungi belonging to the class Trichomycetes, but now considered to be members of the opisthokont
The opisthokonts () are a broad group of eukaryotes, including both the ...
and
Amoebidiales
Amoebidiidae is a family of single-celled eukaryotes, previously thought to be zygomycete fungi belonging to the clasTrichomycetes but molecular phylogenetic analysesBenny, G. L., and O'Donnell, K. 2000. ''Amoebidium parasiticum'' is a protozoa ...
), Mendoza ''et al.'' suggested changing the name to Mesomycetozoea, which refers to their evolutionary position. On Eukaryota tree, in
Opisthokont
The opisthokonts () are a broad group of eukaryotes, including both the animal and fungus kingdoms. The opisthokonts, previously called the "Fungi/Metazoa group", are generally recognized as a clade. Opisthokonts together with Apusomonadida and ...
clade, Mesomycetozoea is in the middle ("Meso-") of the fungi ("-myceto-") and the animals ("-zoea"). Note the name Mesomycetozoa (without a third e) is also used to refer to this group, but Mendoza ''et al.'' use it as an alternate name for basal Opisthokonts.
Phylogeny
Taxonomy
* Class Ichthyosporea Cavalier-Smith 1998
** Order
Dermocystida
Dermocystida is an order of parasitic eukaryotes.
Taxonomy
* Family Rhinosporidiaceae Mendoza et al. 2001
** Genus '' Amphibiocystidium'' Pascolini et al. 2003
** Genus '' Chromosphaera'' Grau-Bové et al. 2017
** Genus '' Dermocystidium'' Pé ...
Cavalier-Smith 1998
*** Family Rhinosporidiaceae Mendoza et al. 2001
**** Genus '' Amphibiocystidium'' Pascolini et al. 2003
**** Genus '' Chromosphaera'' Grau-Bové et al. 2017
**** Genus ''
Dermocystidium
''Dermocystidium'' is a genus of cyst-forming, parasitic eukaryotes of fish, which are the causative agents of dermocystidiosis.
Taxonomic History
The genus ''Dermocystidium'' was described in 1907. It was previously thought to be a genus of fu ...
'' Pérez 1908 'Amphibiothecum''_Feldman,_Wimsatt_&_Green,_2005;_''Dermocystis.html" ;"title="Amphibiothecum.html" ;"title="'Amphibiothecum">'Amphibiothecum'' Feldman, Wimsatt & Green, 2005; ''Dermocystis">Amphibiothecum.html" ;"title="'Amphibiothecum">'Amphibiothecum'' Feldman, Wimsatt & Green, 2005; ''Dermocystis'' Pérez 1907 non]
**** Genus ''Dermosporidium'' Carini 1940
**** Genus ''Dermotheca''
**** Genus ''Rhinosporidium'' Minchin & Fantham 1905
**** Genus ''Sphaerothecum'' Arkush et al. 2003 (Rosette agent)
**** Genus '' Valentines (genus), Valentines'' Borteiro et al. 2018
** Order
Ichthyophonida
Ichthyophonida is an order of parasitic eukaryotes.
Taxonomy
Members of Ichthyophonida include:
* Amoebidiaceae
**'' Amoebidium''
***'' Amoebidium appalachense''
***'' Amoebidium parasiticum''
* Paramoebidiidae
**'' Paramoebidium''
***'' P ...
Creolimax
''Creolimax fragrantissima'' is a single-celled protist that occupies a key phylogenetic position to understand the origin of animals. It was isolated from the digestive tract of some marine invertebrates, mainly from the peanut worm, collected ...
Psorospermium
''Psorospermium haeckeli'' (or ''Psorospermium haeckelii'') is a parasitic species.
References
Parasitic opisthokonts
Mesomycetozoea
{{Holozoa-stub ...
'' Hilgendorf 1883 non Eimer 1870]
**** Family Piridae Cavalier-Smith 2012
***** Genus ''Caullerya'' Chatton 1907
***** Genus ''Abeoforma'' Marshall & Berbee 2011
***** Genus '' Pirum'' Marshall & Berbee 2011
*** Suborder Trichomycina Cavalier-Smith 2012
**** Genus †'' Paleocadus'' Poinar 2016
**** Family
Amoebidiidae
Amoebidiidae is a family of single-celled eukaryotes, previously thought to be zygomycete fungi belonging to the clasTrichomycetes but molecular phylogenetic analysesBenny, G. L., and O'Donnell, K. 2000. ''Amoebidium parasiticum'' is a protozoa ...
Lichtenstein 1917 ex Kirk et al. 2001
***** Genus ''
Amoebidium
''Amoebidium'' is a genus of unicellular, symbiotic eukaryotes in the Opisthokont group Mesomycetozoea, family Amoebidiidae.Reynolds, N.K., M.E. Smith, E.D. Tretter, J. Gause, D. Heeney, M.J. Cafaro, J.F. Smith, S.J. Novak, W.A. Bourland, M.M ...
'' Cienkowski 1861
**** Family Ichthyophonidae Cavalier-Smith 2012
***** Genus ''
Ichthyophonus
''Ichthyophonus'' is a genus of unicellular eukaryotic parasites of fish. They were once considered to be fungi, but phylogenetic evidence suggests they are protists related to both fungi and animal
Animals are multicellular, eukaryotic ...
'' Plehn & Mulsow 1911
**** Family
Paramoebidiidae
ParamoebidiidaeReynolds, N.K., M.E. Smith, E.D. Tretter, J. Gause, D. Heeney, M.J. Cafaro, J.F. Smith, S.J. Novak, W.A. Bourland, M.M. White. 2017. Resolving relationships at the animal-fungal divergence: A molecular phylogenetic study of the prot ...
Reynolds et al. 2017
***** Genus ''
Paramoebidium
''Paramoebidium'' is a genus of unicellular, symbiotic eukaryotes that inhabit the digestive tract of immature freshwater arthropod hosts (e.g. black fly larvae, mayfly and stonefly nymphs).Lichtwardt, R.W., M.J. Cafaro, M.M. White. 2001. The T ...
Pistillaria
''Typhula'' is a genus of clavarioid fungi in the order Agaricales. Species of ''Typhula'' are saprotrophic, mostly decomposing leaves, twigs, and herbaceous material. Basidiocarps (fruit bodies) are club-shaped or narrowly cylindrical and are ...
'' Jeekel et al. 1959 non Fries 1821; '' Recticoma'' Scheer 1935; '' Trichella'' Léger & Duboscq 1929; '' Trichellopsis'' Maessen 1955]
***** Genus '' Enteromyces'' Lichtwardt 1961
***** Genus ''
Enteropogon
''Enteropogon'' is a genus of tropical and subtropical plants in the grass family. It is widespread across many parts of Asia, Africa, Australia, the Americas, and various islands.Leidyomyces'' Lichtwardt et al. 1999
***** Genus '' Palavascia'' Tuzet & Manier 1947 ex Lichtwardt 1964
***** Genus '' Paramacrinella'' Manier & Grizel 1971
***** Genus '' Passalomyces'' Lichtwardt et al. 1999
***** Genus '' Ramacrinella'' Manier & Ormiéres 1962 ex Manier 1968
***** Genus '' Taeniella'' Léger & Duboscq 1911
***** Genus '' Taeniellopsis'' Poisson 1927