Abstract Detail

Systematics Section / ASPT

Moore, Michael J. [2], Jansen, Robert K. [2], Tye, Alan [1].

Long-distance dispersal in Tiquilia subg. Tiquilia (Boraginaceae): North America, South America, and the Galápagos Islands.

Disjunction between the desert regions of North and South America is a common feature of the flora of these continents, occurring in dozens of genera and species. Tiquilia subg. Tiquilia provides a good example of such amphitropical disjunctions: of the 18 species within this subgenus, 3 species occur in the deserts of western North America, 11 species occur in the deserts of coastal Perú and Chile, and 1 species occurs both in western North America and in Argentina. The remaining three species in the subgenus are endemic to the Galápagos Islands. To determine the biogeographic history of subg. Tiquilia, a robust molecular phylogeny of Tiquilia was constructed, including species from all sections of subg. Tiquilia, using the chloroplast marker rps16. Reconstruction of biogeographic history based on this phylogeny indicates a North American origin for subg. Tiquilia, as well as a complex history of long-distance dispersal among North America, South America, and the Galápagos Islands. The biogeographic analysis requires a minimum of four long-distance dispersal events to explain the current distribution of subg. Tiquilia, and also indicates that three of the four extant North American lineages of subg. Tiquilia have colonized South America. These results contribute to a growing body of recent molecular evidence that long-distance dispersal events between North and South America have occurred relatively frequently during the biogeographic history of the American deserts.

1 - Charles Darwin Research Station, Department of Botany, Puerto Ayora, Santa Cruz, Galapagos Islands, , Ecuador
2 - University of Texas at Austin, Section of Integrative Biology, 1 Universiy Station, #A6700, Austin, Texas, 78712, USA

Keywords:
biogeography
phylogeny
amphitropical disjuncts
Tiquilia
Boraginaceae
Galapagos Islands
rps16 intron
long-distance dispersal
Galápagos Islands.

Presentation Type: Paper
Session: 43-7
Location: Cottonwood A (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 9:30 AM
Abstract ID:29