Taxonomy and the evolutionary history of Micropeltidaceae

Micropeltidaceae species are flyspeck fungi which have been subjected to few systematic studies. We re-examined 27 genera which were accepted in the Micropeltidaceae and re-described them based on herbaria materials and protologues. Based on morphology and phylogenetic investigations, we transfer Micropeltidaceae to a new order, Micropeltidales (Lecanoromycetes). Genera with bluish or greenish upper walls (Dictyopeltella, Dictyothyriella, Dictyothyrina, Dictyothyrium, Haplopeltheca, Micropeltis, Scolecopeltidium and Stomiopeltopsis) are accepted in the new taxonomic concept for Micropeltidaceae. A molecular clock approach estimated the divergence time of the Micropeltidaceae crown group at 130 (165-104) Mya, which also supports its rank as an order (diverging from 220-100 Mya). The evolutionary histories between Micropeltidaceae species and host plants are interpreted by cophylogenetic analyses calibrated by their divergence times. The result indicates that the diversification of Angiospermae (130-80 Mya) fosters the formation of genera of Micropeltidaceae mainly via cospeciation events, and this codivergent period would be an important reference when establishing generic boundaries of epifoliar fungi.