Abstract Detail

Systematics Section/ASPT

Reginato, Marcelo [1], Kriebel, Ricardo [2].

On the anther morphospace and evolutionary trends in the tribe Miconieae (Melastomataceae).

The tribe Miconieae has ca. 1800 species distributed throughout the neotropical region. Molecular phylogenies have uncovered several local radiations inside the tribe, as well the extensive polyphyly of its genera. Parallel evolutionary trends are seen in anther form in the Miconieae, where shifts from elongate to shorter anthers and from minute-pored to large-pored or slit-like dehiscent anthers are reported in the literature. On the one hand, convergence in stamen morphology has contributed to artificial generic and sectional circumscriptions in the Miconieae. At the same time these observed patterns might help clarify our understanding of flower evolution in the group. Most species in the Melastomataceae have buzz pollinated flowers that offer pollen as a reward to female bees. Buzz pollinated flowers usually have large anthers with thick walls, showy colors and poricidal dehiscence. Interestingly, some shifts to more generalized pollination syndromes that involve short, white anthers with large dehiscence areas as well as to dioecy, have been suggested in the group. Nonetheless, most studies have been restricted to scattered lineages within Miconieae and/or have treated anther variables such as shape discretely. Here, we describe major trends of anther evolution in the Miconieae, providing a new framework for such studies in the Melastomataceae. We gathered morphological, climatic and distributional data for 432 species of Miconieae, for which a molecular phylogeny is available. The morphological dataset includes anther and pore size measurements and shape scores (from elliptical Fourier analysis), as well discrete variables such as color. In this study we describe anther morphology continuously, present morphospaces, estimate phylogenetic signal and describe trends for major lineages of Miconieae. We assess whether anther size, shape, color and pore size are associated with elevation, climatic variables and distributional range sizes. We test the hypotheses that shifts to generalist pollinators is associated with higher elevations, given that bees are less common in such environments, or if they tend to be white colored and less conspicuous than their specialized counterparts, among others. Additionally, we identified shifts in anther morphology across the tribe and discuss correlations among anther variables. Finally, the level of sympatry and anther similarity among species is discussed.

1 - The New York Botanical Garden, Institute Of Systematic Botany, 2900 Southern Blvd., Bronx, NY, 10458, USA
2 - University of Wisconsin, Department of Botany, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Melastomataceae
Morphospace
flower evolution
Comparative analysis.

Presentation Type: Oral Paper:Papers for Sections
Session: 19
Location: Salon 9/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 3:00 PM
Number: 19007
Abstract ID:1035
Candidate for Awards:None