Molecular phylogeny supports the recognition of the two morphospecies Parmotrema pseudotinctorum and P. tinctorum (Parmeliaceae, Ascomycota)

Abstract

Here we provide an example of a combined genetic and morphologic approach in a taxonomic re-evaluation in lichen forming fungi to resolve a log-standing controversy. We used nuclear ITS and mitochondrial SSU rDNA sequences to determine species delimitation in Parmotrema tinctorum, sensu M. Hale. We sampled 50 specimens representing the morphospecies from Africa, Asia, Australia, and Europe, and generated 92 new sequences of mitochondrial and nuclear ribosomal DNA. The results revealed two divergent and strongly supported monophyletic clades, in which isidium morphology of the samples was concordant with both groups. Samples clustered in Clade I are recognized as P. tinctorum, characterized with thin cylindrical isidia growing either on bark, or rocks, while specimens grouped in Clade II are characterized by thick, coarse and somewhat globular isidia and mainly grow on rock. The name P. pseudotinctorum is resurrected here for this last clade, corresponding with the commonly growing foliose lichen species present in the Canary archipelago, but not P. tinctorum. Consequently, we discussed the possibility that P. tinctorum had been present in the past in Canary Is. and been lost through over-collecting for the dye industry in the 19th century