Abstract Detail

Systematics Section/ASPT

Iles, William [1], Smith, Selena [2], Graham, Sean [3].

Dating early events in monocot phylogeny.

A suite of recent monocot fossil discoveries and reviews of the monocot and angiosperm fossil record make re-evaluating monocot divergence times timely. Here we updated a large-scale plastid-based data set to include 172 species representing 71 out of 78 monocot families. We reconstructed phylogenetic relationships using parsimony, partitioned maximum likelihood and Bayesian methods, and dated the monocot tree using Bayesian approaches, constraining multiple node dates using age distributions based on fossil evidence (17 monocot fossils and fossils for eight other angiosperms). Our overall estimate of higher-order monocot phylogeny is generally congruent with other recent studies, and typically has at least as much support for individual branches. We infer that most higher-order monocot diversity arose in the Cretaceous (i.e., ~80% of family stem ages). The crown ages of only eight families date to the Cretaceous, and only one of those dates to the Lower Cretaceous (Araceae, Alismatales). Our family crown age estimates tend to be younger than those inferred in the well-cited Jannsen and Bremer (2004) study, but our ages for orders are more comparable, and are among the oldest monocot ordinal ages inferred in recent studies. For example, we infer that the crown of the order Alismatales arose within a few million years of the origin of monocots.

Broader Impacts:

1 - University of British Columbia, Department of Botany, 3529 - 6270 University Boulevard, Vancouver, V6T 1Z4, BC, CANADA
2 - University of Michigan, Earth & Environmental Sciences and Museum of Paleontology, 1100 North University Ave., 2534 CC Little Building, Ann Arbor, MI, 48109, USA
3 - University of British Columbia, Department of Botany, 3529 - 6270 University Boulevard, Vancouver, BC, V6T 1Z4, CANADA

Keywords:
Monocots
Monocotyledons
molecular dating
Higher-order phylogeny.

Presentation Type: Oral Paper:Papers for Sections
Session: 48
Location: Elmwood/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 1:30 PM
Number: 48001
Abstract ID:806
Candidate for Awards:None