Intercontinentally disjunct species are derived rather than relictual in the moss genus Daltonia (Bryophyta)

We present a phylogenetic analysis of the moss genus Daltonia based on nucleotide sequences from three plastid loci (psbT, trnL, trnG) plus the nuclear ribosomal RNA gene (ITS), including 9 of 21 species in this genus. Of the nine species, seven are well-supported as monophyletic, even when multiple accessions came from different continents. Early diverging species in the genus have relatively restricted ranges that are limited to a single continent, whereas most or all later-diverging species have broad intercontinental distributions. The observation that intercontinental distributions are repeated in multiple monophyletic species suggests that a key innovation underlying enhanced abilities for long dispersal evolved within Daltonia, and that this potential was inherited among derived species from their common ancestor. The nature of this (these) innovation(s) remains obscure, but may be related to both relaxation of ecological limitations on establishment, and to effective dispersal of spores per se.