Abstract Detail

Macroevolution

Benítez-Villaseñor, Adriana [1], Magallon, Susana [2].

Perianth Structure across Eudicotiledoneae, and its relationship with Diversification.

Flowering plants (Angiospermae) display an extraordinary diversity of floral structural configuration and morphological variation. Floral structural stabilization often allows architectural elaboration associated with specialized reproductive syndromes, including complex associations with pollinators. The eudicot clade (Eudicotyledoneae) contains over 70% of angiosperm species. It consists of an early-diverging grade of mostly depauperate lineages and a very large clade, Pentapetalae, which contains the vast majority of the species of the group. The early-diverging eudicot lineages encompass a wide variety of floral structural configurations, including a diversity of phylotactic and meristic patterns, in which perianth organs are mostly undifferentiated. In contrast to the variable floral structure of early-diverging eudicots, many of the lineages within Pentapetalae are characterized by a fixed floral structure consisting of a pentamerous meristic organization in the perianth and androecium, and a bipartite perianth with morphologically distinct organs, forming the calyx and the corolla. This basic Pentapetalae floral pattern has been greatly elaborated along many different lineages, to constitute complex floral architectural configurations. Nevertheless, it is not entirely clear where exactly within the eudicot phylogenetic tree did the Pentapetalae floral pattern evolve, or if it represents a homologous attribute among Pentapetalae. In this study, we investigate the distribution of the bipartite perianth across eudicots, and evaluate its relationship with increased rate of species diversification. We documented the distribution of the bipartite perianth across 638 species representing 297 eudicot families in a time-calibrated phylogenetic tree, in the context of a strict exemplar approach. Data about floral structure was obtained by combining observations from fresh material, herbarium specimens, and published information. The evolution of the bipartite perianth was reconstructed with the Mk2 model. Subsequently, we investigated the possible link between shifts to a bipartite perianth, and other structural characters, and the rates of speciation and extinction using BiSSE in the R package Diversitree. Our results provide an estimation of the number and phylogenetic placement of shifts to a bipartite perianth, and reconstructions of the ancestral perianth structure in major eudicot lineages, including eudicots as a whole. These results provide a framework for further detailed evaluation of floral evolution across eudicots, in particular, correlations among different structural characters.

1 - Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de Méxi, 3er Circuito de Ciudad Universitaria, Del. Coyoacán , México, D.F., 04510, México
2 - Instituto De Biologia, Universidad Nacional Autonoma De Mexico, 3er Circuito De Ciudad Universitaria, Del. Coyoacan, A.P. 70-233, Mexico City, Mexico D.F., N/A, 04510, Mexico

Keywords:
Diversification
BiSSE
macroevolution
floral structure
Pentapetalae
eFLOWER.

Presentation Type: Oral Paper:Papers for Topics
Session: 3
Location: Salon 3/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 9:15 AM
Number: 3006
Abstract ID:613
Candidate for Awards:None