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Abstract Detail

Systematics Section/ASPT

Gernandt, David S. [1], Holman, Garth [2], Campbell, Christopher S. [3], Stockey, Ruth A. [4], Rothwell, Gar W. [5].

Stricter taxon selection criteria and implied character weighting increases phylogenetic resolution of living and fossil Pinaceae.

Including fossils in phylogenetic analyses permits clearer hypotheses of the evolutionary history of groups, but imperfectly preserved or fragmentary fossil taxa can be difficult to place with confidence. The structural diversity of fossil seed cones suggest that the family Pinaceae was represented by both Abietoid and Pinoid lineages in the early Cretaceous, but phylogenetic analyses of extant and fossil Pinaceae taxa have resulted in poorly resolved consensus trees with low overall branch support as measured by the bootstrap. Using a matrix of 159 morphological characters, 59 kb of DNA sequence from plastid exons, and 2 kb of nuclear phyP sequences, we evaluated several strategies for phylogenetic inference of extant and fossil taxa: 1) identifying and pruning taxa with an unstable position by using a reduced consensus technique, 2) excluding fossil taxa that lack diagnostic characters (cone scale apices and seeds), and 3) implied character weighting. Parsimony and Bayesian analyses of combined datasets for living taxa only resulted in well resolved consensus trees that recovered Pinoid genera (Cathaya, Larix, Picea, Pinus, and Pseudotsuga) as monophyletic and differed mainly in whether Abietoid genera (Abies, Keteleeria, Cedrus, Pseudolarix, Tsuga, and Nothotsuga) were monophyletic or rendered paraphyletic by varying placements of the root to the family. When treating extant taxa only, including DNA sequence data resulted in substantially increased branch support and in better-resolved consensus trees. However, including DNA did not result in stable placement of fossil taxa in strict consensus trees. Moderate increases in branch support and resolution were obtained both by using the reduced consensus pruning technique and by excluding fossils lacking seed cone scale apices and seeds from the analysis, but use of implied character weighting resulted in the greatest increase in branch support and resolution. We identified a subset of Late Jurassic and Cretaceous fossils that captures the structural diversity of the family and is represented by relatively abundant, well-preserved material.

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1 - Instituto De Biologia, UNAM, Apartado Postal 70-233, Coyoacan, Mexico, N/A, 04510, Mexico
2 - University Of Maine, School Of Biology And Ecology, 5735 Hitchner Hall, Orono, ME, 04469, USA
3 - University Of Maine, Department Of Biological Sciences, 261 Hitchner Hall, Orono, ME, 04469-5735, USA
4 - Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, USA
5 - Oregon State University and Ohio University, Botany and Plant Pathology, 2082 Cordley Hall, Oregon State University, Corvallis, OR, 97331, US


Presentation Type: Oral Paper:Papers for Sections
Session: 33
Location: Salon 10/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:30 AM
Number: 33007
Abstract ID:729
Candidate for Awards:None

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