Molecular systematics and character evolution in the lichen family Ramalinaceae (Ascomycota: Lecanorales)

Abstract

The Ramalinaceae is the fourth-largest family of lichenized ascomycetes with 42 genera and 913 species exhibiting considerable morphological variation. Historically, generic boundaries in the Ramalinaceae were primarily based on morphological characters. However, molecular systematic investigations of subgroups revealed that current taxonomy is at odds with evolutionary relationships. Tropical members of the family remain particularly understudied, including the large genus Phyllopsora. We have generated and collected multilocus sequence data (mtSSU, nrITS, nrLSU, RPB1, RPB2) for 149 species associated with the Ramalinaceae and present the first comprehensive molecular phylogeny of the family. We used ancestral state reconstructions on our molecular family phylogeny to trace the evolution of character states. Our results indicate that the Ramalinaceae have arisen from an ancestor with long, multiseptate ascospores living in humid temperate forests, and that the phyllopsoroid growth form has evolved multiple times within the family. Based on our results using integrative taxonomy, we discuss sister-relations and taxon-delimitation within five well-supported clades: The Bacidia, Biatora-, Ramalina-, Rolfidium-, and Toninia-groups. We reduce six genera into synonymy and make 49 new nomenclatural combinations. The genera Bacidia, Phyllopsora, Physcidia and Toninia are polyphyletic and herein split into segregates. We describe the two genera Bellicidia and Parallopsora and resurrect the genera Bibbya, Kiliasia, Sporacestra, and Thalloidima. According to our new circumscription, which also includes some additional changes, the family Ramalinaceae now comprises 39 genera.

Three new species of Krogia (Ramalinaceae, lichenised Ascomycota) from the Paleotropics

“…The two genera are anatomically distinct (Timdal 2002), although both form small squamules or lobes on bark. A comprehensive molecular phylogeny of the family Ramalinaceae, however, revealed the type species of the two genera to belong to different major clades within the family (Kistenich et al in press). They are therefore not as closely related as previously anticipated.…”

“…Krogia differs from Bacidina s.str. (sensu Kistenich et al in press) in having spirally arranged ascospores and a non- to weakly amyloid ascus tholus.…”

“…DNA sequences of the two previously described Krogia species were generated from specimens in B and O and from a specimen provided by P. Diederich (hb Diederich). Additionally, we included 14 mtSSU and 12 ITS sequences (Table 1) from nine species in six genera known to be closely related to Krogia as well as from the holotype of the genus Krogia , K.coralloides , from a previous molecular study on the family Ramalinaceae (Kistenich et al in press). …”

“…A. Massal. and B.sipmanii M. Brand et al, were used as outgroup in all phylogenetic analyses based on the molecular phylogeny of the Ramalinaceae (Kistenich et al in press). We checked for incompatibilities amongst gene trees by subjecting each marker to a simple maximum likelihood bootstrap analysis as implemented in RAxML Black Box 8.2.10 (Stamatakis 2014) on the CIPRES webserver (Miller et al 2010) with default settings.…”

“…There are no published sequences of Krogia , but we have provided sequences of the mitochondrial small subunit (mtSSU) and of the nuclear ribosomal transcribed spacer region (ITS) from the three putative new species and from two of the three previously described species. The sequences, some of which were taken from an unpublished paper on the phylogeny of the Ramalinaceae (Kistenich et al in press), were used to infer a phylogeny.…”