Abstract Detail

Biogeography

Koenemann, Daniel [1], Burke, Janelle [2].

A New Phylogeny and Biogeographic History Reconstruction for Coccoloba (Polygonaceae).

Plant life in the New World tropics is notably diverse. This diversity is often highlighted in taxonomic groups that have evolved in conjunction with the uplift of the Andes Mountains or the formation of the islands of the West Indies. Yet, plants are also diverse in continental Neotropical lowlands, the flora of which is only now becoming systematically well-documented. The genus Coccoloba consists of trees and woody vines, common in low elevation Neotropical forests. Estimates for the number of species in Coccoloba have ranged widely, being as high as 400 species and as low as 120 species. This is, in part, because Coccoloba species are difficult to differentiate using morphological characters. Geographically, the genus is distributed throughout the Neotropics. In spite of this wide distribution, the concentration of species varies considerably throughout its range. Moreover, there appears to be a latitudinal divide within the genus. Species that occur in the Caribbean and Mesoamerica, as a general rule, do not grow in South America, and vice versa. In order to better understand species diversification in Coccoloba, our objective was to reconstruct a molecular phylogeny of Coccoloba species and use this phylogeny to reconstruct the biogeographical history of these species. We reconstructed our phylogeny using three chloroplast regions (rbcL, trnL-F, and psbA-trnH) and a maximum likelihood criterion. We then reconstructed the biogeographic history of the species using parsimony character mapping. Brazil has the largest concentration of Coccoloba species. Therefore, we hypothesized that Brazil would be the geographical origin of the genus, and that the Brazilian species would be the most basal in the phylogeny. Preliminary results indicate that, contrary to our hypothesis, the Brazilian species are not basal but form the crown group of the phylogeny, being derived from species in Mesoamerica and the Caribbean. The biogeographic reconstructions place the origin of the genus in Mesoamerica, where it first dispersed to the Caribbean, followed by northern and then southern South America.

1 - Howard University, Biology Department, 415 College Street, NW, Washington , DC, 20059, USA
2 - Howard University, Dept. Of Biology, 415 College St. NW, Just Hall 328, Washington, DC, 20059, United States

Keywords:
biogeography
Coccoloba
phylogeny
maximum likelihood
Parsimony
Mesoamerica
Caribbean 
Brazil.

Presentation Type: Poster
Session: P, Biogeography Posters
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PBG004
Abstract ID:399
Candidate for Awards:None