title: Geographical structure, narrow species ranges, and Cenozoic diversification in a pantropical clade of epiphyllous leafy liverworts.
abstract: The evolutionary history and classification of epiphyllous cryptogams are still poorly known.Leptolejeuneais a largely epiphyllous pantropical liverwort genus with about 25 species characterized by deeply bilobed underleaves, elliptic to narrowly obovate leaf lobes, the presence of ocelli, and vegetative reproduction by cladia. Sequences of three chloroplast regions (rbcL,trnL-F,psbA) and the nuclear ribosomal ITS region were obtained for 66 accessions ofLeptolejeuneaand six outgroup species to explore the phylogeny, divergence times, and ancestral areas of this genus. The phylogeny was estimated using maximum-likelihood and Bayesian inference approaches, and divergence times were estimated with a Bayesian relaxed clock method.Leptolejeunealikely originated in Asia or the Neotropics within a time interval from the Early Eocene to the Late Cretaceous (67.9 Ma, 95% highest posterior density [HPD]: 47.9-93.7). Diversification of the crown group initiated in the Eocene or early Oligocene (38.4 Ma, 95% HPD: 27.2-52.6). Most species clades were established in the Miocene.Leptolejeunea epiphyllaandL. schiffnerioriginated in Asia and colonized African islands during the Plio-Pleistocene. Accessions of supposedly pantropical species are placed in different main clades. Several monophyletic morphospecies exhibit considerable sequence variation related to a geographical pattern. The clear geographic structure of theLeptolejeuneacrown group points to evolutionary processes including rare long-distance dispersal and subsequent speciation.Leptolejeuneamay have benefitted from the large-scale distribution of humid tropical angiosperm forests in the Eocene.
authors.affiliation: Department of Biology I, Systematic Botany and Mycology GeoBio-Center University of Munich (LMU) Munich Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Bechteler
authors.affiliation: Herdwangen-Schönach Germany.
authors.forename: Alfons
authors.initials: A
authors.lastname: Schäfer-Verwimp
authors.affiliation: Department of Biology I, Systematic Botany and Mycology GeoBio-Center University of Munich (LMU) Munich Germany; School of Marine and Environmental Sciences University of Malaysia Terengganu Kuala Terengganu Terengganu Malaysia.
authors.forename: Gaik Ee
authors.initials: GE
authors.lastname: Lee
authors.affiliation: Department of Biology I, Systematic Botany and Mycology GeoBio-Center University of Munich (LMU) Munich Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Feldberg
authors.affiliation: Department of Biology I, Systematic Botany and Mycology GeoBio-Center University of Munich (LMU) Munich Germany.
authors.forename: Oscar Alejandro
authors.initials: OA
authors.lastname: Pérez-Escobar
authors.affiliation: Botany Department Eszterházy University Eger Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Pócs
authors.affiliation: Instituto de Botânica São Paulo SP Brazil.
authors.forename: Denilson F
authors.initials: DF
authors.lastname: Peralta
authors.affiliation: Royal Botanic Gardens and Domain Trust Sydney NSW Australia.
authors.forename: Matthew A M
authors.initials: MA
authors.lastname: Renner
authors.affiliation: Department of Biology I, Systematic Botany and Mycology GeoBio-Center University of Munich (LMU) Munich Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Heinrichs
keywords: Leptolejeunea; ancestral area estimation; bryophyte; cryptic speciation; divergence time estimation; epiphyte; phylogeny