title: Anatomical diversity and regressive evolution in trichomanoid filmy ferns (Hymenophyllaceae): a phylogenetic approach.
abstract: To infer the anatomical evolution of the Hymenophyllaceae (filmy ferns) and to test previously suggested scenarios of regressive evolution, we performed an exhaustive investigation of stem anatomy in the most variable lineage of the family, the trichomanoids, using a representative sampling of 50 species. The evolution of qualitative and quantitative anatomical characters and possibly related growth-forms was analyzed using a maximum likelihood approach. Potential correlations between selected characters were then statistically tested using a phylogenetic comparative method. Our investigations support the anatomical homogeneity of this family at the generic and sub-generic levels. Reduced and sub-collateral/collateral steles likely derived from an ancestral massive protostele, and sub-collateral/collateral types appear to be related to stem thickness reduction and root apparatus regression. These results corroborate the hypothesis of regressive evolution in the lineage, in terms of morphology as well as anatomy. In addition, a heterogeneous cortex, which is derived in the lineage, appears to be related to a colonial strategy and likely to a climbing phenotype. The evolutionary hypotheses proposed in this study lay the ground for further evolutionary analyses that take into account trichomanoid habitats and accurate ecological preferences.
authors: Centre de recherche sur la paléobiodiversité et les paléoenvironnements, université Pierre-et-Marie-Curie, UMR 7207 CNRS-MNHN-UPMC, bâtiment de géologie, CP48, 57, rue Cuvier, 75005 Paris, France. jdubuiss@snv.jussieu.fr
authors: Jean-Yves
authors: JY
authors: Dubuisson
authors: Sabine
authors: S
authors: Hennequin
authors: Sophie
authors: S
authors: Bary
authors: Atsushi
authors: A
authors: Ebihara
authors: Elodie
authors: E
authors: Boucheron-Dubuisson
mesh_terms: D044822:Biodiversity; D005075:Biological Evolution; D002965:Classification; D029624:Ferns / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics*; D016013:Likelihood Functions; D010802:Phylogeny; D018517:Plant Roots / Q000033:anatomy & histology / Q000502:physiology; D018547:Plant Stems / Q000033:anatomy & histology / Q000502:physiology; D013045:Species Specificity