Abstract Detail

Systematics

Sharber, Wyatt [1], Whitlock, Barbara [2].

Independent origins of Ayenia (Malvaceae) in the Caribbean.

The diverse and endemic Caribbean flora has biogeographic ties to North, Central, and South America, yet few Caribbean plant lineages have been investigated in detail. The New World genus Ayenia is an excellent system for understanding the assemblage of dry-adapted Caribbean communities. Mexico and the Caribbean combined are a center of diversity for the genus and have been hypothesized to be its center of origin as well. We reconstructed a well-sampled phylogeny of Ayenia using three chloroplast DNA markers to test hypotheses on the number, timing, and geographic origins of Caribbean lineages. A time calibrated phylogeny and alternative biogeographic models indicate that Ayenia originated in the mid-Miocene in South America after the last possible land bridge connecting islands of the Caribbean with the continental Americas. Long distance dispersal is thus the only mechanism for establishment of Ayenia in the Caribbean. Our results suggest two major independent radiations northward. The first occurred in the early Pliocene within a clade of Ayenia with relatively large seeds, with migration from South America into Central America and Mexico before 1-2 dispersals into the Caribbean. A later radiation northward occurred in the mid-Pliocene in a clade with smaller seeds, with some support for dispersal from South America to the Caribbean, followed by dispersal to the North American mainland. Timing of Caribbean invasions in both clades correspond with global drying and cooling during the Pliocene, potentially expanding dry habitats in the Caribbean, as well as the closing of the Isthmus of Panama, which may have affected oceanic dispersal patterns. Relationships among Caribbean and Mexican taxa are not fully resolved, but indicate a dynamic process of dispersal among islands and mainland regions. Future analyses using whole plastid sequences will provide stronger tests whether the Caribbean served as an alternative route into North America.

1 - University of Miami, Dept. of Biology, 1301 Memorial Dr., Coral Gables, FL, 33146, United States
2 - University Of Miami, Department Of Biology, P.O. Box 249118, CORAL GABLES, FL, 33124-0421, USA

Keywords:
Malvaceae
biogeography
Caribbean.

Presentation Type: Oral Paper
Session: 19, ASPT Cooley Awards
Location: Sundance 5/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 10:30 AM
Number: 19010
Abstract ID:430
Candidate for Awards:George R. Cooley Award