While in some cases, phylogenetic data and chemical metabolites have been successful in characterizing lichen species ( LaGreca, 1999 Kroken and Taylor, 2001b Tehler and Kallersjo, 2001 Lumbsch et al., 2008 Fehrer et al., 2008 Lücking et al., 2008), in other cases, chemical compounds did not correspond to monophyletic clades ( Buschbom and Mueller, 2006 McCune et al., 2011). Patterns of chemical metabolites have also been widely applied to circumscribe species in lichens because morphological characters are often scarce or show considerable phenotypic plasticity. Some of these lichens exhibited slight, almost cryptic, morphological, chemical, or ecological differences that supported the recognition of new species (for an in-depth discussion, see Crespo and Pérez-Ortega, 2009 Crespo and Lumbsch, 2010). ( Grube and Kroken, 2000 Kroken and Taylor, 2001b Molina et al., 2004, 2011 Argüello et al., 2007 Baloch and Grube, 2009 Wirtz et al., 2008 Núñez-Zapata et al., 2011 Leavitt et al., 2012 Thues et al., 2015). This is the case in several studies, which challenged the morphological species concept because a number of individuals belonging to a morphological species were unexpectedly clustered in reciprocally monophyletic groups these morphological species initially claimed to be cryptic species. While in traditional systematics phenotypical differences have been used to separate lichen species, the molecular phylogenetic approach, based on the analysis of DNA, at times suggests relationships that differ from those that arise from traditional systematics. More diversity is encountered in the fungal component, which usually dominates the association and produces diverse growth forms, sexual structures, and secondary chemistry ( Grube and Winka, 2002). Lichens are slow-growing and very long-living symbiotic associations of fungi with green algae or cyanobacteria, whose physiologies, tissues, and organs change in appearance as a direct consequence of symbiosis ( Chapman and Margulis, 1998). These findings are discussed in the context of evolutionary hypotheses for speciation processes. In three clades, this study found evidence for diversification processes between isidiate and nonisidiate specimens (species-pair). meridionalis-group appear to be monophyletic but remain as allopatric cryptic species. Several chemical compounds were found to be neither stable nor invariant characters. These clades associate with different photobionts and comprise 18 known species and 5 undescribed species. Within Lobaria, three major clades were found. Phylogenetic analyses confirmed the monophyly of the genus Lobaria, including L. Split decomposition and haplotype networks suggest complex evolutionary histories of species within the East Asian L. The genus Lobaria and most of its species were strongly supported statistically. meridionalis-group was additionally studied using split decomposition and haplotype network analysis. Morphological and chemical patterns of 87 individuals were examined and three independent nuclear loci were sequenced. To critically examine the relationships between species identified via morphological and chemical criteria, phylogenetic species recognition (PSR) was applied to the genus Lobaria. Particularly in East Asia, this genus includes many rare and poorly known taxa that are circumscribed as morpho- or chemospecies, as well as species-pairs. The lichen genus Lobaria is widely distributed in old-growth forests. Accurate species delimitation has critical implications for ecological and conservation studies.
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