title: Species delimitation and evolution in morphologically and chemically diverse communities of the lichen-forming genus Xanthoparmelia (Parmeliaceae, Ascomycota) in western North America.
abstract: OBJECTIVE
  Accurate species delimitation is important for understanding the diversification of biota and has critical implications for ecological and conservation studies. However, a growing body of evidence indicates that morphology-based species circumspection in lichenized fungi misrepresents fungal diversity. The foliose lichen genus Xanthoparmelia includes over 800 species displaying a complex array of morphological and secondary metabolite diversity.
  
  
  METHODS
  We used a multifaceted approach, applying phylogenetic, population genetic, and genealogical analyses to delimit species in a single well-supported monophyletic clade containing 10 morphologically and chemically diverse Xanthoparmelia species in western North America. Sequence data from four ribosomal and two low-copy, protein-coding markers, along with chemical and morphological data were used to assess species diversity.
  
  
  RESULTS
  We found that traditionally circumscribed species are not supported by molecular data. Rather, all sampled taxa were better represented by three polymorphic population clusters. Our results suggest that secondary metabolite variation may have limited utility in diagnosing lineages within this group, while identified populations clusters did not reflect major phylogeographic or ecological patterns.
  
  
  CONCLUSIONS
  In contrast to studies revealing previously undiscovered fungal lineages masked within lichen species circumscribed by traditional morphological and chemical concepts, the present study suggests that species diversity has been overestimated in the species-rich genus Xanthoparmelia.
authors: Department of Biology and the M. L. Bean Life Science Museum, 401 WIDB, Brigham Young University, Provo, Utah 84602, USA. sleavitt@fieldmuseum.org
authors: Steven D
authors: SD
authors: Leavitt
authors: Leigh
authors: L
authors: Johnson
authors: Larry L
authors: LL
authors: St Clair