The chalara-like anamorphs of Leotiomycetes

Abstract

AbstractThe chalara-like anamorphs of Leotiomycetes are phialidic hyphomycetes with cylindrical collarettes and deeply seated sporulating loci, and hyaline, aseptate or septate, cylindrical conidia. They are commonly found on plant litters in both terrestrial and submerged environments, and with broad geographical distribution. This paper reports our research result of diversity, taxonomy and phylogeny of these fungi in China, which is based on a systematic study by using an integrated approach of literature study, morphological observation and phylogenetic analyses of 153 chalara-like fungal species with diversified morphology in conidiomata, setae, conidiophores, phialides and conidia. The phylogenetic analyses employing different datasets of SSU, LSU and ITS sequences of 116 species showed that these chalara-like fungi were paraphyletic and scattered in 20 accepted genera belonging to five families of Leotiomycetes: Arachnopezizaceae, Hamatocanthoscyphaceae, Helotiaceae, Neolauriomycetaceae and Pezizellaceae. Additional six genera,Ascoconidium,Bioscypha,Chalarodendron,Didonia,PhaeoscyphaandTapesina, all reported with chalara-like anamorphs in literatures, are also accepted as members of Pezizellaceae or Leotiomycetes genera incertae sedis. Among of these 26 accepted genera of chalara-like fungi in Leotiomycetes, 17 genera are asexually typified genera (Ascoconidium,Bloxamia,Chalara,Chalarodendron,Constrictochalara,Cylindrochalara,Cylindrocephalum,Leochalara,Lareunionomyces,Minichalara,Neochalara,Neolauriomyces,Nagrajchalara,Parachalara,Stipitochalara,XenochalaraandZymochalara), and 9 are sexually typified genera (Bioscypha,Bloxamiella,Calycellina,Calycina,Didonia,Hymenoscyphus,Mollisina,PhaeoscyphaandTapesina). The phylogenetic significance of conidial septation in generic delimitation was further confirmed; while other morphologies such as conidiomata, setae, conidiophores, phialides, conidial length, and conidial ornamentation have little phylogenetic significance, but could be used for species delimitation. The polyphyletic genusChalaras. lat. is revised with monophyletic generic concepts by redelimitation ofChalaras. str. in a narrow concept, adaption of the emendedCalycinato also include asexually typified chalara-like fungi, reinstatement ofCylindrocephalum, and introduction of six new genera:ConstrictochalaraW.P. Wu & Y.Z. Diao,LeochalaraW.P. Wu & Y.Z. Diao,MinichalaraW.P. Wu & Y.Z. Diao,NagrajchalaraW.P. Wu & Y.Z. Diao,ParachalaraW.P. Wu & Y.Z. Diao andStipitochalaraW.P. Wu & Y.Z. Diao.Chaetochalarabecomes a synonym ofChalaras. str., and the known species are disassembled intoChalaras. str. andNagrajchalara. The polyphyletic genusBloxamiais also redefined by introducing the new genusBloxamiellaW.P. Wu & Y.Z. Diao forB.cyatheicola. Five existing species ofChalaras. lat. were excluded from Leotiomycetes and reclassified:Chalara breviclavataasChalarosphaeria breviclavataW.P. Wu & Y.Z. Diao gen. et sp. nov. in Chaetosphaeriaceae,C.vacciniiasSordariochalara vacciniiW.P. Wu & Y.Z. Diao gen. et sp. nov. in Lasiosphaeriaceae, and three otherChalaraspecies with hyaline phialides,C.hyalina,C.schoenoplectiandC.siamenseas combinations ofPyxidiophorain Pyxidiophoraceae. For biodiversity of these fungi in China, a total of 80 species in 12 genera, including 60 new species, 17 new records and 1 new name, were discovered and documented in this paper. In addition, five species including three new species are reported from Japan. In connection to this revision, a total of 44 new combinations are made. The identification keys are provided for most of these genera. Future research area of these fungi should be the phylogenetic relationship of several sexually typified genera such asBioscypha,Calycellina,Calycina,Didonia,Phaeoscypha,RodwayellaandTapesina, and systematic revision of existing names under the generaBloxamia,ChaetochalaraandChalara.