Rostania revised: testing generic delimitations in Collemataceae (Peltigerales, Lecanoromycetes)

Abstract

Here, we test the current generic delimitation of Rostania (Collemataceae, Peltigerales, Ascomycota) utilizing molecular phylogeny and morphological investigations. Using DNA sequence data from the mitochondrial SSU rDNA and two nuclear protein-coding genes (MCM7 and β-tubulin) and utilizing parsimony, maximum likelihood and Bayesian phylogenetic methods, Rostania is shown to be non-monophyletic in the current sense. A new generic delimitation of Rostania is thus proposed, in which the genus is monophyletic, and three species (Rostania coccophylla, R. paramensis, R. quadrifida) are excluded and transferred to other genera. Rostania occultata is further non-monophyletic, and a more detailed investigation of species delimitations in Rostania s. str. is needed. The new combinations Leptogium paramense and Scytinium quadrifidum are proposed.