Abstract Detail

The flora of Madagascar: uncovering mechanisms for diversification

Van Ee , Benjamin [1], Berry, Paul [2], Kainulainen, Kent [3].

Croton (Euphorbiaceae) in the Old World: using the widespread distribution of a group to calibrate a molecular clock in the absence of fossils.

With over 150 species, Madagascar may contain approximately 10% of the worldwide diversity of Croton (Euphorbiaceae). While numerous undescribed species of Croton from Madagascar await description, the number of synonymous names from the region is also approximating the number of accepted names. All phylogenetic evidence to date points to a single dispersal event of the genus to the island, which further highlights the explosive diversification that it has undergone there. There have been subsequent dispersal events from Madagascar to the Mascarenes, the Comoros, and mainland Africa. The lack of any known Croton fossils has limited the ability to calibrate a molecular clock for the genus, but its widespread distribution across oceanic islands, putatively once-connected landmasses, and other features that can serve as age constraints has made it possible to generate a time-calibrated phylogenetic hypothesis. The inferred historical ocean currents provide further evidence for why Croton's arrival on Madagascar was a rarer event compared to its subsequent dispersal from Madagascar.

1 - University of Puerto Rico-Mayaguez, Call Box 9000, Mayaguez, Puerto Rico, 00680, Puerto Rico
2 - University Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, MI, 48108, United States
3 - University of Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, MI, 48108, USA

Keywords:
Madagascar
molecular dating
Molecular phylogeny.

Presentation Type: Colloquium Presentations
Session: C08, The flora of Madagascar: uncovering mechanisms for diversification
Location: 101/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 2:00 PM
Number: C08003
Abstract ID:905
Candidate for Awards:None