How important are conidial appendages?

Abstract

The genus The genus Dinemasporium is used as a case study to evaluate the importance of conidial appendages for generic level classification of coelomycetous fungi. Based on morphology and sequence data of the large subunit nuclear ribosomal RNA gene (LSU, 28S) and the internal transcribed spacers and 5.8S rRNA gene of the nrDNA operon, the genus Dinemasporium is circumscribed, and an epitype designated for D. strigosum, the type of the genus. A further five species are introduced in Dinemasporium, namely D. pseudostrigosum (isolated from Triticum aestivum, Germany and Stigmaphyllon sagraeanum, Cuba), D. americana (soil, USA), D. polygonum (Polygonum sachalinense, Netherlands), D. pseudoindicum (soil, USA), and D. morbidum (human sputum, Netherlands and hare dung, New Zealand). Brunneodinemasporium, based on B. brasiliense, is introduced to accommodate Dinemasporium-like species with tightly aggregated brown conidiogenous cells, and pale brown conidia. Dendrophoma (= Amphitiarospora) is reinstated as distinct from Dinemasporium, and an epitype designated for D. cytisporoides, characterised by its superficial, stipitate to cupulate conidiomata, and small conidia with two polar, tubular, exogenous appendages. The genus Stauronema is reduced to synonymy under Dinemasporium. Pseudolachnea (1-septate conidia) is supported as distinct from Dinemasporium (aseptate conidia), and P. fraxini introduced as a novel species. Taxa in this generic complex differ by combination of morphological characters of conidiomata, setae, conidia and appendages. Appendage morphology alone is rejected as informative at the generic level.