Acaulospora intravesiculata, a new species in the Glomeromycota from Taiwan

Abstract

The spores of Acaulospora intravesiculata sp. nov. were discovered from the mountain area of National Yu-shan Park, central Taiwan and Taipingshan recreational park, northern Taiwan. This new species was presented here based on combined morphological and molecular analyses. The spores of the new fungus are 160-200 mu m in diameter, subglobose to globose, pale yellow to yellow, and with three spore walls. The type of spore ontogeny is unique by producing spores directly within sporiferous saccules and is first described here as "entrosacculoid" as a special type of acaulosporoid spore formation. At maturity, the spore is enveloped by a hyaline, ephemeral outer wall which is a part of sporiferous saccule and attached to a thin-walled saccule stalk. After collapse of the hyphal stalk of the saccule, spores are very similar to those of other Acaulospora species. Based on partial SSU-ITS-LSU sequences, a monophyletic clade is formed within a major clade of the Acaulosporaceae, with A. intravesiculata in a separate clade together with A. koskei. Morphologically, both species can be distinguished not only by the type of spore formation, but also by the pigmentation of the mature spores which are orange brown to yellow brown in A. koskei.