The Gymnosperm AToL: Results of analysis of morphological characters

ROTHWELL, GAR; STEVENSON, DENNIS; ESCAPA, IGNACIO; MAPES, GENE; STOCKEY, RUTH; ICKERT-BOND, STEFANIE; CAMPBELL, CHRISTOPHER; GERNANDT, DAVID; HOLMAN, GARTH; KELCH, DEAN; LITTLE, DAMON; MATHEWS, SARAH

New Orleans

Congreso; Botany 2013; 2013

One of the major goals of the gymnosperm AToL has been to develop a comprehensive matrix that utilizes morphological characters of living and fossil taxa that can be included in combined molecular/morphological analyses of seed plants. Additional goals of the morphological work are to explore the role of extinct species in resolving the unstable overall pattern of seed plant phylogeny. We compare results, that either include or exclude extinct species, to test competing hypotheses that have been developed using other sets of characters, and to predict the most fruitful approaches for future phylogenetic studies of clades with a long geological history and high levels of extinction. The current morphological matrix includes 275 taxa (i.e., 198 ?core taxa? of living seed plants and 77 extinct species) and 387 characters from all facets of the plant life cycle, and has been analyzed using the parsimony software TNT. Preliminary analyses yield a topology of seed plant relationships that agrees with the anthophyte hypothesis. The general pattern of relationships resolves gnetophytes as the sister to angiosperms, and cycads+ginkgo as the sister group to conifers. Living conifers, gnetophytes, and cycads all resolve as monophyletic. Monophyly of living conifer families is also recovered (Cupressaceae is collapsed when fossils are included), and most living gymnosperm genera are monophyletic. Taxon resampling analyses were performed to test the robustness of relationships among extant groups, and to assess the influence of fossils on those phylogenetic hypotheses.