Epigeocarpum Błaszk., B.T. Goto, Jobim, Niezgoda & Marguno, gen. nov.
MycoBank number: MB 838879; Index Fungorum number: IF 838879; Facesoffungi number: FoF;
Etymology: Latin, Epigeocarpum, Epigeo (=soil surface) and carpum (=fruit body), referring to the habitat, in which the type species of the new genus formed glomerocarps (=sporocarps).
Type species: E. crypticum Jobim, Błaszk., Niezgoda, Magurno & B.T. Goto
Diagnosis: Differs from K. bistrata, the phylogenetically closely related species of the monospecific genus Kamienskia, in (i) producing compact, epigeous, yellow-colored glomerocarps with a peridium and hyaline to light yellow, glomoid spores having a three-layered spore wall, of which the laminate layer 2 is relatively thick compared to the small spores size, contracts and, consequently, transfers into a crown-like structure in spores crushed in PVLG-based mountants and stains in Melzer’s reagent; (ii) the possession of a septum separating the spore subtending hyphal lumen from the spore interior; and (iii) the nucleotide composition of sequences of the 18S-ITS-28S nuc rDNA region and the rpb1 gene.
Genus description: Producing glomoid glomerocarps in a compact epigeous unorganized glomerocarp. Spores hyaline to light yellow (4A4), usually globose to subglobose, 34–46 µm diameter, with a spore wall consisting of three permanent, smooth layers. Spore wall layer (swl) 2 laminate, usually transferring into a crown-like structure due to contracting in spores crushed in PVLG and PVLG Melzer’s reagent. Only swl 2 stains in Melzer’s reagent. Subtending hypha funnel-shaped with a wall continuous with swl 1 and 2 and an open pore at the spore base; the channel connecting the lumen of the subtending hypha with the interior of spores closed by a septum continuous with swl 3; the septum usually positioned at half the thickness of swl 2; the subtending hyphal lumen gradually narrowing in maturing spores due to thickening of subtending hyphal wall layer 2.
Species
E. crypticum