Abstract
The paper presents the results of morphological studies, as well as comparisons and phylogenetic analyses of sequences of the 45S (= 18S-ITS-28S) nuc rDNA region and the rpb1 gene (when available) of four arbuscular mycorrhizal fungi (AMF) of the phylum Glomeromycota. These fungi were (i) an informally named isolate 449, suspected of being an undescribed species of the genus Diversispora, and (ii) three Corymbiglomus species in the family Diversisporaceae. The studies confirmed the novelty of isolate 449 in Diversispora and showed that Corymbiglomus contains only C.corymbiforme, while C.globiferum and C.pacificum should be transferred to a separate genus sister to Corymbiglomus. Consequently, isolate 449 was described as Diversisporaconica sp. nov., C.globiferum, and C.pacificum were placed in Paracorymbiglomus gen. nov. and renamed P.globiferum comb. nov. and P.pacificum comb. nov.