Abstract Detail

Systematics Section/ASPT

Aguirre-Santoro, Julian [1], Michelangeli, Fabian [2], Stevenson, Dennis [3].

Systematics, biogeography, and morphological evolution of the Ronnbergia Alliance (Bromeliaceae), an undescribed clade within the Core Bromelioideae.

The phylogenetic relationships, taxonomic implications, biogeography, and morphological evolution of the here described Ronnbergia Alliance (Bromeliaceae, Bromelioideae) were investigated. In order to reconstruct the phylogenetic relationships of the group, we used three chloroplast and three nuclear DNA sequence markers combined with a wide species sampling across the taxonomically conflictive core Bromelioideae clade and a nearly complete a species-level sampling for the Ronnbergia Alliance. Our main results indicate that the Ronnbergia Alliance is a robust monophyletic group sister to the remaining core Bromelioideae, and it is composed by species of the polyphyletic genera Aechmea, Hohenbergia and Ronnbergia. We identified two major internal lineages with high geographic structure within the Ronnbergia Alliance. The first of these lineages, called the Pacific clade, contains species of Aechmea and Ronnbergia that occur exclusively from southern Central America to northwestern South America. The second clade, called the Atlantic clade, contains species of Aechmea, Hohenbergia and Ronnbergia mostly limited to two centers of distribution, the central corridor of the Atlantic Forest and the Greater Antilles. Ancestral character reconstructions permitted identifying thirteen potentially diagnostic characters for Ronnbergia and its subclades. For instance, we found that the combination of tubular corollas apically spreading and unappendaged ovules are diagnostic for the Ronnbergia Alliance, whereas flower size, length of the corolla tube, and petal pigmentation are important characters to differentiate the Pacific and Atlantic clades. Given the robustness of our results and the polyphyly of the genera that compose the Ronnbergia Alliance, we propose a new taxonomic reorganization for this clade, placing all the species of the Pacific clade in Ronnbergia and the species of the Atlantic clade in the resurrected genus Wittmackia. In the case of Wittmackia, we found that it contains a robust monophyletic clade composed exclusively by seventeen species endemic to the northern part of the Caribbean. Because this Caribbean clade has great potential for future evolutionary and conservation studies, we are conducting a complete taxonomic revision of this group. Finally, we performed biogeographic and evolutionary analyses in order to understand the events that separated the lineages in disjunct centers of diversity and triggered their diversification in these areas. In general, we found two major geographic splits in the history of the clade, each followed by rapid phenotypic evolution and lineage accumulation. This study represents the first species-level approach to partially understand the striking adaptive diversification of the taxonomically conflictive core Bromelioideae.

1 - The New York Botanical Garden, 2900 Southern Boulevard, NYBG - Pfizer Plant Research Laboratory, Bronx, NY, 10458-5126, USA
2 - The New York Botanical Garden, Institute Of Systematic Botany, 2900 Southern Blvd., Bronx, NY, 10458, USA
3 - The NY Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458-5126, USA

Keywords:
Bromeliaceae
Ronnbergia
Aechmea
Hohenbergia
Disjunction
core Bromelioideae.

Presentation Type: Oral Paper:Papers for Sections
Session: 31
Location: Salon 4/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:45 AM
Number: 31004
Abstract ID:728
Candidate for Awards:George R. Cooley Award