title: Phylogeny and species delimitations in European Dicranum (Dicranaceae, Bryophyta) inferred from nuclear and plastid DNA.
abstract: DNA sequences have been widely used for taxonomy, inferring phylogenetic relationships and identifying species boundaries. Several specific methods to define species delimitations based on molecular phylogenies have appeared recently, with the generalized mixed Yule coalescent (GMYC) method being most popular. However, only few studies on land plants have been published so far and GMYC analyses of bryophytes are missing. Dicranum is a large genus of mosses whose (morpho-)species are partly ill-defined and frequently confused. To infer molecular species delimitations, we reconstructed phylogenetic trees based on five chloroplast markers and nuclear ribosomal ITS sequences from 27 out of 30 species occurring in Europe. We applied the species delimitation methods GMYC and Poisson tree processes (PTP) in order to compare their discriminatory power with species boundaries inferred from the molecular phylogenetic reconstructions and with the morphological species concept. Phylogenetic circumscriptions were congruent with the morphological concept for 19 species, while eight species were molecularly not well delimited, mostly forming closely related species pairs. The automated species delimitation methods achieved similar results but tended to overestimate the number of potential species and exposed several incongruences between the morphological concept and inference from molecular phylogenetic reconstructions. It is concluded that GMYC and PTP methods potentially provide a useful and objective way of delimiting bryophyte species, but studies on further bryophyte data sets are necessary to infer whether incongruences might ensue from evolutionary processes and to test the suitability of these approaches.
authors.affiliation: Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Leiden University, Leiden, The Netherlands. Electronic address: annick.lang55@gmail.com.
authors.forename: Annick S
authors.initials: AS
authors.lastname: Lang
authors.affiliation: Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Bocksberger
authors.affiliation: Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Leiden University, Leiden, The Netherlands.
authors.forename: Michael
authors.initials: M
authors.lastname: Stech
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D044002:Bryophyta / Q000145:classification* / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics*; D018742:DNA, Chloroplast / Q000235:genetics*; D016013:Likelihood Functions; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D018742:DNA, Chloroplast
keywords: Bryophyte; Chloroplast markers; DNA-based taxonomy; Morphological plasticity; Species boundaries; nrITS