Dominikia lithuanica and Kamienskia divaricata: new species in the Glomeromycota

New species in the genera Dominikia and Kamienskia (Glomeromycota) are characterized based on morphology and sequences of SSU–ITS–LSU nrDNA and the RPB1 gene. Both species produce glomoid spores only in clusters. Spores of Dominikia lithuanica are hyaline to pale yellow and 22–52 μm in diameter when globose. In their three-layered spore wall, layers 1 and 2 are almost equal in thickness and much thinner than the structural laminate layer 3. Spore wall layers 1 and 3 usually stain faintly in Melzer’s reagent. Spores of Kamienskia divaricata remain hyaline regardless of age, are 10–24 μm in diameter and have a spore wall with two layers of nearly the same thickness. The laminate layer 2 usually shows a faint dextrinoid reaction in Melzer’s reagent. A further conspicuous character of K. divaricata spores is a relatively wide subtending hypha at the spore base. In the field, D. lithuanica and K. divaricata have so far been found only twice and once, respectively, and only in maritime sand dunes of the Curonian Spit, Lithuania (D. lithuanica), and South Africa (K. divaricata). Sequence data available in public databases suggest that D. lithuanica has not yet been detected by other researchers, and K. divaricata also occurs in Texas, USA.