Lichens that incorporate cyanobacterial symbionts
(cyanolichens) are an ecologically key group of species
used as biomonitors at all latitudes. Cyanolichen
evolution is however based on intense studies of few keystone
species and the bulk of species diversity, especially of
small species in cold climates, has yet to be accounted for in
phylogenetic studies. We assembled an expanded data set
including members of all nine currently accepted
Peltigeralean families as well as hitherto undersampled representatives
of small, radially symmetrical, placodioid cyanolichen
genera from the Northern and Southern
Hemispheres. Bayesian and maximum likelihood consensus
trees from our multilocus analyses (nuSSU, nuLSU and
mtSSU) recovered the genera Koerberia, Vestergrenopsis
and Steinera as a new, fully supported, family-level clade
within the Peltigerales. This clade is further supported by a
posteriori morphological analysis and we describe it here as
the new family Koerberiaceae. The recently described and
physiognomically similar genus Steineropsis, by contrast, is
recovered as sister to Protopannaria in the Pannariaceae
(Collematineae). Previous analyses have recovered strong
monophyletic groups around Pannariaceae, Lobariaceae and
Peltigeraceae.We discuss in detail the phylogenetic relationships
of all these taxa, provide a pan-Peltigeralean overview
of phenotypic characteristics and illustrate all major ascus
apical structures. Our topology provides strong backbone
support for the sister relationship of Peltigerineae to
Collematineae as well as for most currently recognized
families of the Peltigerales. The following new combinations
are made: Steinera symptychia (Tuck.) T. Sprib. &
Muggia, and Vestergrenopsis sonomensis (Tuck.) T. Sprib.
& Muggia.
