Hispidopannaria and Phormopsora, two new and small, but evolutionary old Pannariaceae lichen genera from southern South America

Abstract

Based on phylogenetic analyses of the ITS, nuclear large subunit rRNA, mitochondrial small subunit rRNA, and MCM7 genes, species previously treated as <i>Pannaria hispidula</i> and <i>P. isabellina</i> are shown to represent two new Pannariaceae genera, <i>Hispidopannaria</i> and <i>Phormospsora</i>. Each genus forms monophyletic clades, both in multilocus phylogeny and in single gene phylogenies. In the multilocus phylogeny, both genera together formed a monophyletic clade as a sister group to the genus <i>Pannaria</i>, whereas this monophyly was not maintained in single gene phylogenies. <i>Hispidopannaria</i> differs from <i>Pannaria</i> in having large, geotropically arranged, hispid squamules, IKI+ internal ascus structures, and perispores with irregular pulvinate verrucae and apical extensions. The southern South American, TLC-negative species <i>H. hispidula</i> is generitype and is concentrated to trunks in the evergreen <i>Nothofagus</i> forests of south-central Chile. <i>Psoroma dasycladum</i>, a similar endemic species from the Juan Fernández Archipelago, is also transferred to <i>Hispidopannaria</i>. <i>Phormopsora</i> is monospecific and is the only member of Pannariaceae which contains norstictic and connorstictic acids. Its thallus of large, branched squamules with large, foliose cephalodia and its bullate perispores with long-apiculate apical extensions also separate it from <i>Pannaria</i>. Its species, <i>Phormopsora isabellina</i>, has a similar distribution as <i>H. hispidula</i> on the South American mainland, but is more widespread. The position of these two small genera as a sister group to the large and diverse genus <i>Pannaria</i>, indicates a long period of slow evolutionary rate, with the island endemic <i>Hispidopannaria dasyclada</i> as an exception. Reproductive isolation and photobiont specialization are partly suggested to explain their slow evolution and lack of surviving speciation.