Of the nearly 300 species of the phylum Glomeromycota comprising arbuscular mycorrhizal fungi (AMF), only 24 were originally described to form glomoid spores in unorganized sporocarps with a peridium and a gleba, in which the spores are distributed randomly. However, the natural (molecular) phylogeny of most of these species remains unknown. We found unorganized sporocarps of two fungi-producing glomoid spores: one in the Amazonian forest in Brazil (tropical forest) and the second in a forest of Poland (temperate forest). The unique spore morphology of the two fungi suggested that they are undescribed species. Subsequent phylogenetic analyses of sequences of the small subunit-internal transcribed spacer-large subunit nrDNA region and the RPB1 gene confirmed this assumption and placed the Brazilian fungus in a separate clade at the rank of genus, very strongly divergent from its sister clade representing the genus Glomus sensu stricto in the family Glomeraceae (order Glomerales). The Polish fungus was accommodated in a sister clade to a clade grouping sequences of Diversispora epigaea, a fungus that also occasionally produces spores in sporocarps, belonging in the Diversisporaceae (Diversisporales). Consequently, the Brazilian fungus was here described as the new genus and new species Sclerocarpum gen. nov. and S. amazonicum sp. nov., respectively. The Polish fungus was described as D. sporocarpia sp. nov. In addition, the supposed reasons for the low representation of sporocarpic species in the Glomeromycota were discussed and the known distribution of sporocarp-producing Glomeromycota was outlined.

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As a result of phylogenomic, phylogenetic, and morphological analyses of members of the genus Claroideoglomus, four potential new glomoid spore-producing species and Entrophospora infrequens, a new order, Entrophosporales, with one family, Entrophosporaceae (=Claroideoglomeraceae), was erected in the phylum Glomeromycota. The phylogenomic analyses recovered the Entrophosporales as sister to a clade formed by Diversisporales and Glomeraceae. The strongly conserved entrophosporoid morph of E. infrequens, provided with a newly designated epitype, was shown to represent a group of cryptic species with the potential to produce different glomoid morphs. Of the four potential new species, three enriched the Entrophosporales as new Entrophospora species, E. argentinensis, E. glacialis, and E. furrazolae, which originated from Argentina, Sweden, Oman, and Poland. The fourth fungus appeared to be a glomoid morph of the E. infrequens epitype. The physical association of the E. infrequens entrophosporoid and glomoid morphs was reported and illustrated here for the first time. The phylogenetic analyses, using nuc rDNA and rpb1 concatenated sequences, confirmed the previous conclusion that the genus Albahypha in the family Entrophosporaceae sensu Oehl et al. is an unsupported taxon. Finally, the descriptions of the Glomerales, Entrophosporaceae, and Entrophospora were emended and new nomenclatural combinations were introduced.

Examination of fungal specimens collected in the Atlantic rain forest ecosystems of Northeast Brazil revealed many potentially new epigeous and semihypogeous glomerocarp-producing species of the phylum Glomeromycota. Among them were two fungi that formed unorganized epigeous glomerocarps with glomoid spores of almost identical morphology. The sole structure that distinguished the two fungi was the laminate layer 2 of their three-layered spore wall, which in spores of the second fungus crushed in PVLG-based mountants contracted and, consequently, transferred into a crown-like structure. Surprisingly, phylogenetic analyses of sequences of the 18S-ITS-28S nuc rDNA and the rpb1 gene indicated that these glomerocarps represent two strongly divergent undescribed species in the family Glomeraceae. The analyses placed the first in the genus Dominikia, and the second in a sister clade to the monospecific generic clade Kamienskia with Kamienskia bistrata. The first species was described here as Dominikia glomerocarpica sp. nov. Because D. glomerocarpica is the first glomerocarp-forming species in Dominikia, the generic description of this genus was emended. The very large phylogenetic distance and the fundamental morphological differences between the second species and K. bistrata suggested us to introduce a new genus, here named as Epigeocarpum gen. nov., and name the new species Epigeocarpum crypticum sp. nov. In addition, our analyses also focused on an arbuscular mycorrhizal fungus originally described as Rhizophagus neocaledonicus, later transferred to the genus Rhizoglomus. The analyses indicated that this species does not belong to any of these two genera but represents a new clade at the rank of genus in the Glomeraceae, here described as Silvaspora gen. nov.