Parakarstenia phyllostachydis, a new genus and species of non-lichenized Odontotremataceae (Ostropales, Ascomycota)

The new species Parakarstenia phyllostachydis was discovered on stems of Phyllostachys heteroclada in Sichuan Province of China and is placed in a new genus within Odontotremataceae in this paper. A multigene analysis of a combined nuclear ITS and LSU rDNA and mtSSU sequence dataset and comparable morphologies suggests the taxonomic affinity of the new taxon in this family. Maximum likelihood and Bayesian inference phylogenetic analyses provide evidence that the fungus is best placed in a distinct genus within this family. The new genus is compared with similar genera of Ostropales and a comprehensive description and illustration are offered. Parakarstenia is characterized by its distinct suite of features, such as initially immersed, intracortical, later erumpent and seemingly superficial, sessile and usually gregarious apothecia with a flat to slightly convex, greyish white or pale brown disc; a hairless, buff to yellow receptacle; a non-protruding margin, absent periphysoids and crystals, cylindrical to clavate asci with conical apex and a hemiamyloid (type RR) outer wall; and narrowly cylindrical-clavate to fusoid, vermiform, straight to medium curved, initially non-septate, at maturity transversely multiseptate ascospores. An updated phylogram for Ostropales with selected, predominantly non-lichenized members based on multigene analysis is provided.