Teleomorph-anamorph connections: the new pyrenomycetous genus Carpoligna and its Pleurothecium anamorph.

摘要

Several collections of a pyrenomycete identified as Chaetosphaeria were made from decorticated wood of twigs and branches in Costa Rica, Panama, Puerto Rico and continental USA. Discrete and continuous characters of the ascomata, asci and ascosporesin these collections show that they are very similar morphologically and represent populations of the same species. However, culturing of single ascospore isolates from these collections yielded an anamorph unlike the typical phialidic anamorphs of Chaetosphaeria. This anamorph fits the description of Pleurothecium recurvatum, for which a teleomorph connection has not been yet established. Sequences of the ITS region of the nuclear ribosomal DNA of three collections from Costa Rica, Puerto Rico and USAwere compared and found to be 98% similar. Parsimony and maximum likelihood analyses of sequences of the large subunit nuclear-encoded ribosomal DNA from representative taxa of eight ascomycetous orders show this ascomycete as a monophyletic group distinct from Chaetosphaeria. Statistical analyses of hypothetical trees based on the most parsimonious and the most likely trees rule out phylogenetic affinities of this pyrenomycete to Chaetosphaeria. These analyses suggest possible affinities to the Hypocreales and/or the Microascales. Based on morphology of the anamorph and analyses of ribosomal DNA sequence data, Carpoligna pleurothecii gen. et sp. nov. are described. The implications of the phylogenetic relationships of Carpoligna in the practical identification of morphologically similar pyrenomycetes are discussed.