Scutellospora savannicola: redescription, epitypification, DNA barcoding and transfer to Dentiscutata

© 2014, German Mycological Society and Springer-Verlag Berlin Heidelberg. An arbuscular mycorrhizal fungus (AMF) was isolated from a south Ecuadorian reforestation site in the vicinity of a pristine mountain rainforest ecosystem. Morphologically, it corresponded with the description of an AMF first described from Cuba as Gigaspora savannicola, before it was placed in Scutellospora. No living culture of this species has been available previously to allow detailed morphological review or DNA barcoding. After comparison of the morphology of the holotype and authenticated specimens with that of the Ecuadorian isolate, it was concluded that they are conspecific. A detailed redescription of the species is provided, including morphological characters not included in the original description, and an epitype is designated. To provide an extended DNA barcode for this AMF species, intraspecific variants of the near full-length small subunit rRNA gene (SSU) and a rDNA region comprising part of the SSU, the internal transcribed spacer (ITS) region including the 5.8S rRNA gene, and part of the large subunit rRNA gene (LSU) were sequenced. Phylotaxonomic analyses confirmed the classification in the genus Scutellospora sensu lato in a phylogenetic clade that, based on questionable evidence, was considered to circumscribe a distinct genus, Fuscutata. Recently, this genus was merged with Dentiscutata. Consequently, we move S. savannicola (=Fuscutata savannicola = Gigaspora savannicola) to the genus Dentiscutata (Gigasporaceae).