An additional marine fungal lineage in the Diatrypaceae, Xylariales: Pedumispora rhizophorae

Pedumispora rhizophorae, a marine ascomycete reported only from mangrove habitats, was referred to the Diaporthales on the basis of morphological characteristics. To clarify the phylogenetic classification of P. rhizophorae, we re-examined the morphological features of a recent collection of this fungus and evaluated its taxonomic position at the molecular level. Phylogenetic analyses revealed that P. rhizophorae is distantly placed from the Diaporthales, and groups in the Diatrypaceae, Xylariales with strong support. Pedumispora rhizophorae shares many features with members of the Diatrypaceae, including its saprobic habit on decaying plant material, ascomata embedded in a pseudostroma, the presence of paraphyses and pigmented ascospores. However, P. rhizophorae differs from other members of the Diatrypaceae in that this species has apically truncate asci without an apical apparatus, which deliquesce at maturity, whereas diatrypaceous species have persistent long-stalked asci with a more or less truncate apex. Within the Diatrypaceae, the ascospores of most species are allantoid in shape and unicellular, whereas P. rhizophorae possesses septate, filiform ascospores with apical cells lacking cytoplasm. Filiform ascospores and deliquescing asci are common in many unitunicate marine ascomycetes and are regarded as an adaptation to aquatic environment.