Abstract Detail

Systematics

Penagos Zuluaga, Juan Carlos [1], van der Werff, Henk [2], Park, Brian [3], Eaton, Deren A. R. [4], Comita, Liza [5], Queenborough, Simon [6], Donoghue, Michael [7].

Phylogenetic advances in the Ocotea complex (Supraocotea) are the basis for a phylogenetic classification and understanding of floral character evolution.

The Ocotea complex, which includes ~950 species in 17 genera, contains the greatest diversity of Lauraceae in the Neotropics. In contrast to many angiosperm groups, genera within the Linnean classification system in the Ocotea complex usually contains unrelated species. Currently, genera are delimited by variation in three traditional floral characters: breeding system, number of stamens, and number of anther locules. Earlier molecular phylogenies based on Sanger sequences provided information about relatively recent relationships, supporting the polyphyly of the species-rich Ocotea and suggesting multiple origins for the number of stamens and number of anther locules. However, these phylogenies showed no support for deeper evolutionary relationships. Therefore, using these phylogenies limits our understanding of the evolution of the traditional floral characters used on taxonomy and the ability to delimit monophyletic genera using the same floral characters.

In order to reconcile molecular evidence with floral evolution, we traced the evolution of floral characters and defined and named major clades following the International Code of Phylogenetic Nomenclature. We used restriction-site-associated DNA sequencing to generate phylogenies with samples from 145 species (~15% of the complex) in 15 genera. Our sampling included species for each floral character combination.
Concatenated and coalescence alignments resulted in well-supported phylogenies that i) supported the paraphyly of Ocotea, Licaria, and Aniba; ii) supported the monophyly of Pleurothyrium, Damburneya, and Nectandra; iii) resolved the position of Phyllostemonodaphne, Umbellularia, and the Old-World species of Ocotea. Additionally, Bayesian inference supported iv) multiple reductions to six or to three stamens from a nine-stamen ancestor; v) multiple origins of four- and two-locular anthers; and vi) independent origins of dioecy and gynodioecy from a hermaphroditic ancestor. Based on our RAD-seq trees, we also provided phylogenetic definitions for seven well-supported clades.
Our study provides information about the systematics and multiple origins of floral characters traditionally used to delimit genera in Lauraceae, suggesting they should be used with caution in the future. Moreover, we established a new basis for developing a new phylogenetic classification to promote and facilitate precise communication of clades included in Supraocotea (Ocotea complex) and to orient future research of its evolution and ecology.

1 - Forestry And Environmental School, 195 Prospect St, New Haven, CT, 06511, United States
2 - Missouri Botanical Garden, 4344 Shaw Blvd. , St. Louis, MO, 63110, USA
3 - University of Georgia, Department of Plant Biology, Miller Plant Sciences Bldg, Athens, GA, 30602, USA
4 - Columbia University, Department of Ecology, Evolution and Environmental Biology, New York, NY, 10027, USA
5 - Yale University, School of the Environment, 195 Prospect Stree, New Haven, CT, 06511, USA
6 - Yale University, School of the Environment, 195 Prospect Stree, New Haven, CT, 06511, USA
7 - Yale University, Department Of Ecology And Evolutionary Biology, 21 Sachem St., New Haven, CT, 06511, United States

Keywords:
Lauraceae
floral trait evolution
PhyloCode
phylogenetic nomenclature
breeding systems
RAD-seq data.

Presentation Type: Oral Paper
Session: SYSTIII, Systematics III: Algae to Lilioid Monocots
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 4:15 PM(EDT)
Number: SYSTIII006
Abstract ID:169
Candidate for Awards:None