Testing hypotheses on suprageneric relationships and morphological evolution in the Leucobryaceae (Bryophyta)

Abstract

We studied suprageneric relationships and patterns of morphological character evolution within the moss family Leucobryaceae, based on phylogenetic analyses of markers from all three genomes and representatives from 11 out of 14 genera. Three main lineages are strongly supported within the Leucobryaceae, which display different morphologies of the leaf costa, two dicranoid clades (Campylopus clade and Dicranodontium clade) and a leucobryoid clade. Character evolution analyses resolved the leucobryoid morphology as a synapomorphy for the leucobryoid clade and provided data to evaluate generic circumscriptions within the family. Patterns of molecular variation, species richness, geographical distribution, ecological amplitude and variation in costa structure seem to covary: The two lineages with the most modified morphologies (deviating from the basic dicranoid type; Campylopus and leucobryoid clades) are also the most molecularly variable, species diverse, and occupy the broadest distributions and widest variety of habitats. Most sampled genera have clear morpho-molecular circumscriptions, except Campylopodiella, Dicranodontium and Leucobryum. For the latter, two alternative topologies were resolved (Leucobryum monophyletic or the Asian genera Cladopodanthus and Schistomitrium nested within Leucobryum).