Revision of the genus Splanchospora (Pleosporales, Neohendersoniaceae)

A completely asexual morph of Splanchospora is revealed for the first time. This genus is characterised by clavate-ellipsoid, thick-walled ascospores strongly constricted at the submedian septum, the presence of paraphyses in the conidiomata, and globose to ellipsoid, 1 - celled conidia. Through phylogenetic analyses based on the small subunit (SSU) and large subunit (LSU) of the nuclear ribosomal DNA, the nuclear ribosomal internal transcribed spacer (ITS) region, the second largest RNA polymerase II subunit (RPB 2) gene, and the translation elongation factor 1 - alpha (TEF 1) gene, the genus is clarified to belong to the family Neohendersoniaceae (Pleosporales, Dothideomycetes).

The type species, Splanchospora ampullacea, is neotypified and found to be a species complex. Because of this, we describe four new Splanchospora species, S. fulviconidia sp. nov., S. microspora sp. nov., S. oblongiconidia sp. nov., and S. pseudomicrospora sp. nov. from the twigs of lindens in Japan. All Splanchospora species examined show slight differences in conidial morphology, such as size, shape, and pigmentation.

Species-level analyses suggest that this genus, previously considered to be monotypic, in fact harbours a remarkable diversity of species existing on lindens worldwide.