title: Genetic distances within and among species in monophyletic lineages of Parmeliaceae (Ascomycota) as a tool for taxon delimitation.
abstract: The species delimitation in fungi is currently in flux. A growing body of evidence shows that the morphology-based species circumscription underestimates the number of existing species. The large and ever growing number of DNA sequence data of fungi makes it possible to use these to identify potential cases of hidden species, which then need to be studied with extensive taxon samplings. We used Parmeliaceae, one of the largest families of lichenized fungi as a model. Intra- and interspecific distances derived from maximum-likelihood phylogenetic trees inferred from 491 nuclear ITS rDNA sequences were examined for five major clades of parmelioid lichens. The intra- and interspecific distances were well separated in most cases allowing the calculation of a threshold, with exceptions of highly deviating distances in a few cases. These situations are shown to be taxa in which the current delimitation needs revision. Thus the analysis of the distance distributions is shown to be a powerful tool for identifying species complexes.
authors.affiliation: Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Del-Prado
authors.forename: Paloma
authors.initials: P
authors.lastname: Cubas
authors.forename: H Thorsten
authors.initials: HT
authors.lastname: Lumbsch
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Divakar
authors.forename: Oscar
authors.initials: O
authors.lastname: Blanco
authors.forename: Guillermo Amo
authors.initials: GA
authors.lastname: de Paz
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Molina
authors.forename: Ana
authors.initials: A
authors.lastname: Crespo
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D019143:Evolution, Molecular; D006239:Haplotypes; D016013:Likelihood Functions; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer