The evolution and biogeographic history of epiphytic thalloid liverworts

Among liverworts, the epiphytic lifestyle is not only present in leafy forms but also in thalloid liverworts, which so far has received little attention in evolutionary and biogeographical studies. Metzgeria, with about 107 species worldwide, is the only genus of thalloid liverworts that comprises true epiphytes. In the present study, we provide the first comprehensive molecular phylogeny, including estimated divergence times and ancestral ranges of this genus. Analyses are based on a plastid marker dataset representing about half of the Metzgeria species diversity. We could show for the first time with molecular data that Austrometzgeria is indeed a member of Metzgeria and that the morpho-species M. furcata and M. leptoneura are not monophyletic, but rather represent geographically well-defined clades. Our analyses indicated that Metzgeria started to diversify in the Cretaceous in an area encompassing today’s South America and Australasia. Thus, Metzgeria is one of the few known epiphy...