Abstract Detail

Systematics Section / ASPT

Yoo, Mi-Jeong [2], Bell, Charles D. [1], Soltis, Pamela S. [1], Soltis, Douglas E. [2].

Estimation of divergence times and biogeography of major clades in Nymphaeales.

Nymphaeales (Nymphaeaceae and Cabombaceae) comprise eight genera and ca. 70 species of aquatic plants, with a worldwide distribution in tropical to temperate regions. Phylogenetic relationships among genera of Nymphaeales were very well supported by molecular and morphological data. Based on their robust phylogenetic relationships we estimated the divergence times of major clades in Nymphaeales using DNA sequence data from nuclear 18S rDNA, plastid rbcL, and matK sequences. We applied three different methods, nonparametric rate smoothing (NPRS), penalized likelihood (PL), and the Bayesian method, to estimate divergence times. The results indicate that extant Nymphaeales diversified during the early Tertiary (40~60 million years), and extant Nymphaeaceae date back to ~40 million years. These results show that extant Nymphaeales diversified recently, whereas the Nymphaeles lineage itself is old based on a fossil attributed to this clade from the early Cretaceous (115~125 million years). In addition, we analyzed the biogeographic pattern of major clades in Nymphaeales by dispersal-vicariance analysis. Nymphaeales apparently existed in Eurasia and North America, and the present distribution patterns may be explained by several dispersal and vicariance events.

1 - University of Florida, Department of Natural History, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
2 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA

Keywords:
Nymphaeales
divergence times
biogeographic pattern
dipersal and vicariance.

Presentation Type: Paper
Session: 2-3
Location: Cottonwood A (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 8:30 AM
Abstract ID:636