Stasis and convergence characterize morphological evolution in eupolypod II ferns

• DOI: 10.1093/aob/mct247
• Publication Date: 2013-11-07T01:35:01Z
• Authors: Michael A. Sundue; Carl J. Rothfels
• Keywords: Character evolution; Maximum parsimony; Polyphyly; Convergent evolution; Cladogram; Molecular Phylogenetics

Patterns of morphological evolution at levels above family rank remain underexplored in the ferns. The present study seeks to address this gap through analysis 79 characters for 81 taxa, including representatives all ten families eupolypod II Recent molecular phylogenetic studies demonstrate that large clade (which includes nearly one-third extant fern species) features unexpected patterns. traditional 'athyrioid' ferns are scattered across phylogeny despite their apparent cohesiveness, and mixed among these seemingly conservative taxa morphologically dissimilar groups lack any obvious uniting them with relatives. Maximum-likelihood maximum-parsimony character optimizations used determine unite disparate groups, test whether polyphyly athyrioid is due evolutionary stasis (symplesiomorphy) or convergent evolution. major events reviewed, state concepts reappraised, as a basis further inquiries into morphology. Characters were scored from literature, live plants herbarium specimens, optimized using maximum-likelihood, onto highly supported topology derived maximum-likelihood Bayesian data. Phylogenetic signal tested randomization methods fitdiscrete. majority changes within occur level above. Relative branch lengths data resemble those fit an ancient rapid radiation model (long branches subtended by very short backbone internodes), few clades. circumscribed based upon combination symplesiomorphic homoplastic characters. Petiole vasculature consisting two bundles ancestral eupolypods synapomorphy under deltran optimization. Sori restricted one side vein defines recently recognized comprising Rhachidosoraceae Aspleniaceae, sori on both sides Athyriaceae sensu stricto. results indicate chromosome base number x =41 synapomorphic eupolypods, over two-thirds species. integrated approach synthesizes current hypotheses provides explicit statements families. Strong support found previously clades, whereas unrecognized Sorus position appears be less complicated than hypothesized, linear Diplaziopsidaceae, Hemidictyaceae Rachidosoraceae – lineage only identified. Despite being frequent species, our knowledge it has not been demonstrated state. This first proposed clade, 67 % some light recent results, promotes area remains open original observation.