MSA - Systematics/Evolution
Boehm, Eric W.A. , Schoch, Conrad L. .
Sequencing of five nuclear loci indicates that spore morphology is not a synapomorphic character state in the Mytilinidiaceae (Mytilinidiales, Pleosporomycetidae, Dothideomycetes, Ascomycota).
We are interested in whether morphological features historically used in the delineation of species in the Mytilinidiaceae are phylogenetically informative in the context of sequence-based phylogenies using both coding and non-coding regions. Fungi classified in the genus Mytilinidion and the genus Lophium typically possess strongly laterally compressed, connivent, erect conchate ascomata, reminiscent of miniature bivalve mollusks. They differ however in the shape of their spores. A natural morphological transition series exists, whereby short phragmospores (e.g., M. resinicola & M. tortile) grade into elongate phragmospores (e.g., M. mytilinellum & M rhenanum), which in turn lead to scolecospores (e.g., M. australe & M. scolecosporum), the latter defining subgenus Lophiopsis sensu M.L. Lohman, culminating finally in the filiform spores seen in the genus Lophium (e.g., L. elatum). Surprisingly, sequence data from the ITS, nuSSU, nuLSU, TEF1 and RPB2 clearly indicate that within the genus Mytilinidion spore shape is not a synapomorphic character state. Thus, scolecospores have evolved at least twice within the family. Also, short versus elongate phragmospores do not segregate into separate clades. Lastly, the genus Lophium is ancestral to the genus Mytilinidion, with filiform spores preceding phragmospores & scolecospores in the Mytilinidiaceae. The lack of support for subgenus Lophiopsis, and the lack of spore homogeneity within a clade, thus illustrates a case of convergent evolution in spore morphology within this family.
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Tree of Life (Hysteriales)
1 - Kean University, Biology Department, 1000 Morris Avenue, Union, NJ, 07083, USA
2 - National Center for Biological Information (GenBank), National Library of Medicine, National Institutes of Heath, 45 Center Drive, MSC 6510, Bethesda, Maryland, 20892, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 10:45 AM