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Abstract Detail

Systematics Section/ASPT

Kiel, Carrie [1], McDade, Lucinda [2], Tripp, Erin [3].

Pollinator Mediated Trait Evolution and Floral Diversification of Neotropical Justicia (Acanthaceae).

The monophyletic ‘justicioid’ lineage includes primarily members of pantropical Justicia, the largest genus in Acanthaceae (ca. 600 spp), and several other smaller genera. In this lineage, floral morphology, including size and color as well as inflorescence structure, are remarkably diverse, mirroring that of the entire family. In addition, Justicia is particularly intriguing because it is the only group among Acanthaceae that demonstrates extreme variability in anther morphology: the two stamens may display various combinations of thecae that are parallel/offset, equal/unequal, appendaged/ unappendaged, and have expanded/unexpanded connective tissue. In this study, we expanded taxon sampling in our phylogenetic dataset to include ca.150 taxa from the ‘justicioid’ lineage chosen to represent morphological diversity and geographical distribution, as well as all recognized sections of Justicia from both the Old World (OW) and New World (NW). Using parsimony, Bayesian, and maximum likelihood methods, we confirm earlier results that Justicia is highly polyphyletic. However, all sampled NW Justicia (inclusive of five smaller, mostly monotypic genera long associated with NW Justicia) are together monophyletic with strong support. Interestingly, both floral and anther morphological diversity are centered in the NW Justicia lineage. Our research strongly suggests that this morphological disparity is correlated with pollination syndromes. NW Justicia with hummingbird-pollinated flowers often have thecae that are parallel or nearly so whereas Justicia from the OW, where hummingbirds do not occur, lack this arrangement. Insect-pollinated Justicia from both hemispheres tend to have highly modified anthers with expanded connective tissue, often with spur-like structures and varying degrees of super-positioning of the thecae. We estimate the monophyletic NW Justicia + associated generate to comprise ca. 400 species in comparison to their OW sister group (ca. 200 species). Our hypothesis is that anther morphological diversity, with concomitant evolutionary vagility of pollinator relationships, has been innovative for NW Justicia + associated genera. To test this hypothesis, we (1) reconstructed ancestral states to elucidate evolutionary transitions in characters likely important in pollination syndrome transitions, (2) provide evidence from ordination analyses to quantify trait groupings, and (3) apply results to BISSE analyses to examine comparative diversification patterns.

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Related Links:
Acanthaceae Tree of Life
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1 - Rancho Santa Ana Botanic Garden, 1500 North College Ave., Claremont, CA, 91711, USA
2 - Rancho Santa Ana Botanic Garden, Department of Botany, 1500 N. College Avenue, Claremont, CA, 91711, USA
3 - University of Colorado, Boulder, Museum of Natural History (COLO Herbarium), Department of Ecology and Evolutionary Biology, Boulder, Colorado, 80309, United States

pollination syndromes
floral evolution
morphological characters.

Presentation Type: Oral Paper:Papers for Sections
Session: 49
Location: Marlborough A/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 4:30 PM
Number: 49012
Abstract ID:593
Candidate for Awards:None

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