Eumycetozoa

Eumycetozoa is a clade that includes three groups of amoebozoan protists: Myxogastria, Dictyostelia and Protosporangiida—also known as Myxomycetes, Dictyosteliomycetes and Ceratiomyxomycetes, respectively. It is defined on a node-based approach as the least inclusive clade containing the species Dictyostelium discoideum (a dictyostelid), Physarum polycephalum (a myxogastrid) and Ceratiomyxa fruticulosa (a protosporangiid). All known members of Eumycetozoa generate fruiting bodies, either as sorocarps (in dictyostelids) or as sporocarps (in myxogastrids and protosporangiids). Within their life cycle, they may appear as a single haploid amoeboid cells (in dictyostelids), or as flagellated amoebae with two cilia that give rise to obligate amoebae with no cilia, from which the sporocarps develop (in myxogastrids and protosporangiids). 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. In eumycetozoans where sexual reproduction is well studied, the zygote cannibalizes on haploid amoebae. == Evolution ==

Eumycetozoa is a well supported clade within Amoebozoa. In independent phylogenetic analyses, it has been consistently recovered as the sister group to Archamoebae. The Eumycetozoa+Archamoebae clade is, in turn, the sister group to Variosea. Within Eumycetozoa, Dictyostelia has a basal position while Myxogastria and Protosporangiida form a clade. Together, these three groups are part of the larger clade Conosa. The following cladogram is based on a 2022 analysis: == Taxonomy ==

The name Eumycetozoa was first used by German mycologist Friedrich Wilhelm Zopf in 1884, although no formal taxonomic rank was given. 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). 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. The name Macromycetozoa was suggested earlier, but Eumycetozoa was chosen for being the oldest term. • Amoebozoa • Evosea • Eumycetozoa [=Macromycetozoa ] • Dictyostelia • Myxogastria [=Myxomycetes ] • Protosporangiida 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. == Notes ==