It has been suggested that the absence of anthraquinones is not a synapomorphic character, but appears independently in unrelated lineages of Teloschistaceae. We analyzed ITS nrDNA regions in species of the genus Caloplaca and present evidence for five such examples: the Caloplaca cerina group, C. obscurella, the C. servitiana group, the C. xerica group and the C. variabilis group (Pyrenodesmia). In some cases, loss of anthraquinones is observed only in individuals within ordinarily pigmented populations, but sometimes the loss covers whole lineages containing one or more species. Both situations are observed in the C. servitiana group. Loss of anthraquinones is always followed by the synthesis of ‘alternative’ pigments (often Sedifolia-grey). In the specimens with anthraquinone-containing apothecia studied, these pigments are not visible in apothecial sections after dissolving anthraquinones in K. Fully unpigmented apothecia have not been observed.
The Caloplaca xerica group is a newly established, infraspecific grouping of species related to, and similar to, C. xerica. The Caloplaca servitiana group is also newly established and represents an isolated lineage covering two rather different, but related species. Caloplaca neotaurica is described here as a new species with apothecia of two colour variants; orange-red (with anthraquinones) and grey (with Sedifolia-grey).
The genus Huea represents another taxon lacking anthraquinones within Teloschistaceae. The genera Apatoplaca and Cephalophysis, which lack anthraquinones, are tentatively placed in Teloschistaceae, but their phylogenetic identity has not been recognized. Hueidea is reported to have no anthraquinones, but its secondary metabolites should be studied further and its possible placement in Teloschistaceae assessed.
We suggest that Caloplaca abbreviata var. lecideoides and C. celata represent variants of C. stillicidiorum lacking anthraquinones.