Phylogenetic analysis of Marchantiidae (Marchantiophyta): towards a robustly diagnosed classification

Abstract

During the last decade, phylogenetic analyses of molecular data have deeply impacted over the classification schemes of bryophytes. The increasingly use of molecular data also implied a seldom use of morphological data. As a consequence, many of the proposed classifications are based on unreliable morphological diagnosis. In this contribution, a phylogenetic analysis of Marchantiidae (complex thalloid liverworts) is carried out by including both morphological and molecular datasets. Taxonomic samplinginvolved 41 ingroup species. This is, all the genera, families and orders of Marchantiidae. Outgroupsampling included 27 species and 10 orders of leafy and simple thalloid liverworts altogether.Morphological dataset comprised 118 discrete and 5 continuous characters. Molecular data consisted of11 molecular markers (3 mitochondrial regions, 7 plastid regions and 26S nuclear gene). Phylogenetic analyses were conducted under parsimony as optimality criterion. Performance of different implied weighting settings (standard implied weighting, differential character weighting, differential block weighting) was tested on the ground of trees? stability. In addition, former hypotheses about the relationship between molecular evolution rate and node support/stability are evaluated on the base of randomization tests. Final results are in agreement with most molecular phylogenies. Several new synapomorphies are found in many groups. Previous diagnosing traits are discarded as such or are modified.