Phylogenetic Classification at Generic Level in the Absence of Distinct Phylogenetic Patterns of Phenotypical Variation: A Case Study in Graphidaceae (Ascomycota)

• DOI: 10.1371/journal.pone.0051392
• Publication Date: 2012-12-12T22:07:45Z
• Authors: Sittiporn Parnmen; Robert Lücking; H. Thorsten Lumbsch
• Keywords: Polyphyly; Monophyly

Molecular phylogenies often reveal that taxa circumscribed by phenotypical characters are not monophyletic. While re-examination of identifies the presence characterizing clades, there is a growing number studies fail to identify diagnostic characters, especially in organismal groups lacking complex morphologies. Taxonomists then can either merge or split into smaller entities. Due nature binomial nomenclature, this decision special importance at generic level. Here we propose new approach choose among classification alternatives using combination morphology-based phylogenetic binning and multiresponse permutation procedure test for morphological differences clades. We illustrate use method tribe Thelotremateae focusing on genus Chapsa, group lichenized fungi which our estimate conflict with traditional chemical do show clear pattern. generated 75 DNA sequences mitochondrial SSU rDNA, nuclear LSU rDNA protein-coding RPB2. This data set was used infer estimates maximum likelihood Bayesian approaches. The Chapsa found be polyphyletic, forming four well-supported three clustering one unsupported clade, other, supported clade two subclades. these clades cannot readily separated morphologically, combined binning/multiresponse showed accepting as different genera each reflects pattern significantly better than (or five if splitting first clade). Another species within Thelotremateae, Thelotrema petractoides, unique taxon carbonized excipulum resembling Schizotrema, shown fall outside Thelotrema. Consequently, Astrochapsa, Crutarndina, Pseudochapsa, Pseudotopeliopsis described here 39 combinations proposed.