Abstract Detail

Fossil plants at the intersection of evo-devo and phylogeny: celebrating the contributions of Gar W. Rothwell to biodiversity and evolution

Crepet, William [1], Niklas, Karl [2].

Early Tracheophyte Phylogeny: an experiment.

Only a relatively limited number of vascular plant taxa had evolved by the end of the Devonian and even fewer were well enough known to adequately describe their morphologies with anatomical details. Moreover, the resolution of organographic homologies among ancient organisms that had yet to evolve clear anatomical and reproductive differences among their body parts made the problem of documenting their phylogenetic relationships all the more concerning owing to the high probability of mosaic and convergent evolution. Optimizing the best known Devonian vascular plant taxa with as much diversity as possible, and building upon fine previous analyses, character matrices for 37 taxa were constructed to assess the phylogenetic relationships among early tracheophytes in order to evaluate the status of Equisetum and affinities of the sphenophytes, and to explore four constraints imposed on such analyses: (1) the few diagnostic phenotypic characters preserved in the fossil record of early tracheophytes, (2) ambiguous organographic distinctions among them, (3) the consequences of rapid mosaic evolution, and (4) homoplasy. Despite these constraints, parsimony based phylogenetic analyses generated trees with well-defined branching topologies that were retained regardless of whether a subset of characters was coded as additive or non-additive. In addition, Equisetum was positioned with fossil sphenophytes (e.g., Calamites) as well as with fossils described as ferns or fern-like (e.g., Calamophyton). The interpretation of the phylogenetic relationships among the taxa examined in this study suffers from difficulties associated with identifying homologous characters for poorly preserved organisms lacking well canalized phenotypes.

1 - Section Of Plant Biology, 413 Mann Library, Cornell University, Ithaca, NY, 14853, United States
2 - School Of Integrative Plant Biology, Cornell University, Plant Biology Section, 412 Mann Library, Ithaca, NY, 14853, United States


Presentation Type: Colloquium Presentations
Abstract ID:456
Candidate for Awards:None

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