Abstract Detail

Systematics Section/ASPT

Rothwell, Gar W. [1], Millay, Michael A. [2], Stockey, Ruth A. [3].

Resolving the overall pattern of marattialean fern phylogeny.

Relationships among living species of the Marattiales are considered to be relatively well resolved, but there are ambiguities resulting from the use of alternative outgroups (or their absence), and from a paucity of extinct species included in previous analyses. At the same time, the order has one of the most densely sampled fossil records of all pteridophytic euphyllophytes, with well over 200 extinct species having been described to date. This record provides an opportunity to employ paleontological data to help resolve the deep internal nodes of the marattialean tree and to test hypotheses of crown group topology. Marattiales is well represented in deposits that range from the Pennsylvanian through the Triassic, but sampling density diminishes substantially through the Jurassic. Fossils become rare in the Cretaceous, and are virtually unknown from more recent sediments. In the current study, data for living and extinct marattialean species are combined in a total-evidence phylogenetic analysis. New and previously developed characters are included in a morphological matrix of 93 living+extinct taxa and 94 characters, and are analyzed using maximum parsimony implemented with TNT. Results of this analysis resolve sub-clades in which the living crown-group species all occur in the same subclade, and most of the recently recognized generic groupings of living species are supported. The arrangement of genera, however, differs somewhat from the results of previous analyses, and Marattia resolves as a grade group. Christensenia+Danaea form a monophyletic group attached to the stem of the tree at the base of the clade that includes all living species, and most species of Angiopteris form a clade. However, Angiopteris (Protomarattia) tonkinensis attaches to the stem at an adjacent node. Species of Ptisana and Eupodium each form a monophyletic group attached to the stem of the tree, but species of Marattia s.s. are distributed along the stem as a paraphyletic assemblage. Analysis of living species only yields an almost identical topology for living species. These results support the segregation of Ptisana and Eupodium from Marattia, and yield a topology that is fairly comparable to that proposed by Murdock (2008). Moreover, this living+extinct analysis provides evidence for the overall pattern of phylogeny for the clade, including phylogenetic radiations punctuated by apparent dramatic episodes of extinction and subsequent re-radiation.

1 - Oregon State University and Ohio University, Botany and Plant Pathology, 2082 Cordley Hall, Oregon State University, Corvallis, OR, 97331, US
2 - Ohio University Southern, 1804 Liberty Ave., Ironton, OH, 45638-2279, USA
3 - Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, USA

Keywords:
Marattiales
Phylogeny
morphology
Total Evidence
fossil.

Presentation Type: Oral Paper:Papers for Sections
Session: 33
Location: Salon 10/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:00 AM
Number: 33001
Abstract ID:409
Candidate for Awards:None