Eumycetozoa

Eumycetozoa
	Fuligo septica, a myxogastrid
Scientific classification
Domain:	Eukaryota
Phylum:	Amoebozoa
Subphylum:	Conosa
Infraphylum:	Eumycetozoa; Zopf 1884 ex L.S.Olive 1975 sensu Kang et al. 2017
Clades
	Dictyostelia; Myxogastria; Protosporangiida;
Synonyms
	Macromycetozoa Fiore-Donno et al. 2010; Mycetozoa de Bary, 1859 ex Rostafinski, 1873;

Eumycetozoa (from

protosporangiids

.

Characteristics

Eumycetozoa is a

Ceratiomyxa fruticulosa (a protosporangiid).^[3]^[4]

All known members of Eumycetozoa generate

cilia that give rise to obligate amoebae with no cilia, from which the sporocarps develop (in myxogastrids and protosporangiids).^[4]

The flagellated amoebae of myxogastrids and protosporangiids and non-flagellated amoebae of dictyostelids have a flat cell shape. They form wide pseudopodia with acutely pointed subpseudopodia (i.e. smaller pseudopodia that grow beneath). Unlike other amoebae, the pseudopodia lack a prominent streaming of granular cytoplasm.^[4]

In eumycetozoans where sexual reproduction is well studied, the zygote cannibalizes on haploid amoebae.^[4]

Evolution

Eumycetozoa is a

Protosporangiida form a clade. Together, these three groups are part of the larger clade Conosa.^[3] The following cladogram is based on a 2022 analysis:^[9]

Eumycetozoa

	Myxogastria

	Protosporangiida

Variosea

Taxonomy

The name Eumycetozoa was first used by German

cladistic classification of eukaryotes, where the name was synonymized with Mycetozoa.^[10]

Amoebozoa Lühe, 1913, emend. Cavalier-Smith, 1998
- Eumycetozoa Zopf, 1884, emend. L.S.Olive, 1975 [=Mycetozoa de Bary, 1873]
  - P
    )
  - Myxogastria Macbride, 1899 [=Myxomycetes Link, 1833, emend. Haeckel, 1866]
  - Dictyostelia
    Lister, 1909, emend. L.S.Olive, 1970
  - Incertae sedis Eumycetozoa: Copromyxa, Copromyxella, Fonticula

However, studies in the 2000s decade disproved this hypothesis. Both

ancestral feature shared between all Eumycetozoa, has evolved independently at least in eight lineages within Amoebozoa (e.g. soliformoviids, cavosteliids, schizoplasmodiids, protosporangiids).^[11]^[6] This discovery lead to the conclusion that the entirety of Amoebozoa became a synonym of Eumycetozoa, and was treated as such in the 2012 cladistic classification of eukaryotes. The term Amoebozoa was conserved as a familiar well-established name of popular usage, despite the term Eumycetozoa having priority as the older name.^[12]

To preserve this widely used name, biologist Seungho Kang and his coauthors redefined Eumycetozoa in 2017 to include only one group of protosteloid amoebae, the

Protosporangiida (also known as Ceratiomyxomycetes), which are a monophyletic taxon.^[3]^[7] This usage corresponds to the 1975 hypothesis from Olive that postulates a clade of exclusively fruiting protists that includes myxogastrids, dictyostelids, and some protosteloid amoebae (in this case, the protosporangiids).^[3] As of 2019, this renewed definition is accepted by the scientific community and appears in the modern cladistic classification of eukaryotes, revised by the International Society of Protistologists.^[4] The name Macromycetozoa was suggested earlier,^[13] but Eumycetozoa was chosen for being the oldest term.^[3]

Cavalier-Smith
, 1998
Evosea Kang et al. 2017
Eumycetozoa Zopf 1884 ex L.S. Olive, sensu Kang et al. 2017 [=Macromycetozoa Fiore-Donno et al. 2010]
Dictyostelia
Lister 1909, sensu Sheikh et al. 2018

Haeckel
1866]

Protosporangiida
Shadwick & Spiegel in Adl et al. 2012

The name Mycetozoa was maintained in traditional classifications by some authors like Thomas Cavalier-Smith, who also used a renewed definition to include only protosporangiids. However this scheme did not acquire wide usage.^[5]

Notes

^ Zopf was the first to introduce the name Eumycetozoa, but no rank was given.^[1] Olive reintroduced it in 1975 as a class-level rank.^[2] Finally, in 2017 Kang and his coauthors renewed the definition of Eumycetozoa into its modern usage.^[3]