Dentiscutata colliculosa, a new species in the Glomeromycetes from Northeastern Brazil with colliculate spore ornamentation

A new species of the arbuscular mycorrhiza forming Glomeromycetes was found in semi-arid and semi-humid areas of Northeastern Brazil. It forms brown to black glomerospores that are 330-570 mu m in diameter and have three walls. The spore surface is crowded with fine papillae, and the inner surface of the outer wall has dense and regular colliculate ornamentation. The germination shield is yellow-brown to brown, dentate and is divided by several (8-18) large folds into 8-18 compartments bearing each one germ tube initiation. The morphological features and the molecular analyses on the 18S of the ribosomal gene strongly suggest that the species belongs to the genus Dentiscutata. It is here described under the epithet Dentiscutata colliculosa referring to the novel spore wall ornamentation which renders the new species unique within the Glomeromycetes.