Siphula represents a remarkable case of morphological convergence in sterile lichens

Abstract

A phylogenetic study using large subunit ribosomal DNA sequence data of several species of Siphula, representing all phenotypically recognized species groups, suggests that Siphula is not monophyletic. One lineage, including the core group related to S. ceratites and the S. decumbens group, is placed with members of the Icmadophilaceae, whereas a second distinct lineage, comprising S. complanata, S. fragilis and their relatives, has evolved within the Coccotremataceae. To accommodate these species, the new genus Parasiphula is described as new to science. Parasiphula consists of species restricted to cool to cold latitudes of the Southern Hemisphere. The results show a remarkable case of parallel evolution of lineages that have lost sexual stages and propagate via thallus fragments.

Convergent evolution of a symbiotic duet: The case of the lichen genus Polychidium (Peltigerales, Ascomycota)

“…Our data support the recognition of the hemiangiocarpic ascomatal ontogeny scheme as plesiomorphic and thus a case of parallel evolution in Polychidium , Leptogidium , and several other Peltigeralean genera. Hemiangiocarpy in Peltigeralean lichen fungi thus joins a suite of macro‐ and microscopic parallelisms reported in lichens, all involving partial maintenance of or reversion to ancestral character states (thallus body plans for siphuloid lichens: Grube and Kantvilas, 2006, and for Cladonia : Fontaine et al, 2010; thallus structure, spore septation, and hymenial algae for Verrucariaceae: Gueidan et al, 2007; ascus types: Ekman et al, 2008; ascus disposition: Liu and Hall, 2004).…”

Parallel evolution and phenotypic divergence in lichenized fungi: A case study in the lichen-forming fungal family Graphidaceae (Ascomycota: Lecanoromycetes: Ostropales)

“…Parallel evolution in distantly related or unrelated and phenotypic divergence in closely related lineages have been repeatedly documented in Fungi, including lichenized forms (Grube and Kantvilas, 2006;Hibbett et al, 2007;Larsson and Jeppson, 2008;Lawrey et al, 2009;Mugambi and Huhndorf, 2009;Baloch et al, 2010). Both phenomena are the rule rather than the exception in this kingdom and, as a consequence, the classification of Fungi has undergone substantial changes (Hibbett et al, 2007;Kirk et al, 2008).…”

Lichen Systematics: The Role of Morphological and Molecular Data to Reconstruct Phylogenetic Relationships

“…The placement of the chemically variable genus Siphula in Icmadophilaceae seemed to contradict this statement. However, Siphula is not monophyletic (Stenroos et al 2002a) and the S. complanata and S. fragilis groups with dibenzofurans and depsidones, respectively, were transferred to Parasiphula in the Coccocarpiaceae (Grube and Kantvilas 2006). Incongruence between chemical and molecular data, despite a lack of recombination, was recently detected in Thamnolia vermicularis (Nelsen and Gargas 2009 Lumbsch et al (2005b) described the new genus Gregorella to accomodate the species and found that it was placed in the small family Arctomiaceae (but see Högnabba et al 2009).…”