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Abstract Detail


Biogeography

Cantley, Jason T. [1], Keeley, Sterling [2], Gallaher, Tim [3].

Geoclimatic events in South America influence the evolution of Neotropical Lepidaploinae (Vernonieae: Compositae).

The Vernonieae (Compositae) is the most broadly distributed of all the sunflower family tribes in the Americas. The subtribe Lepidaploinae has an especially large range with 250+ species in 14 genera distributed from Argentina to Mexico. The systematic and biogeographical relationships, however, are largely unknown. A molecular phylogeny was constructed for 115 species of the Lepidaploinae using three chloroplast DNA regions (trnLc-f, ndhF, matK) and the nuclear ITS region. Biogeographic and molecular clock analyses indicate that the Lepidaploinae originated on the Brazilian Shield about 18 million years ago. The subsequent diversification of major lineages is closely tied to geologic and climatic events in South America such as Andean uplift, periodic lowland marine/freshwater incursions and the development of the Amazon Rainforest as an exclusionary habitat barrier. As new habitat was formed on a changing South American continent, Lepidaploinae lineages advanced westward from the Brazilian Shield to the Andes; and then northward, following the uplift of the Andes Mountains. Lepidaploinae lineages reached Central America and the West Indies only within the last four million years, largely as a result of the closure of the Isthmus of Panama and long distance dispersals to various Caribbean islands. Major speciation/extinction events of the last 2.5 my are associated with Quaternary climatic fluctuations, especially in Cerrado habitat of eastern South America.

Broader Impacts:


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1 - University of Hawaii at Manoa, Botany, 3190 Maile Way, St John 101, Honolulu, HI, 96822, USA
2 - University Of Hawaii, DEPT. BOTANY, 3190 MAILE WAY, ROOM 101, Honolulu, HI, 96822-2279, USA
3 - University Of Hawaii At Manoa, Botany, 3190 Maile Way, Room 101, Honolulu, HI, 96822, USA

Keywords:
biogeography
South America
Cerrado
Seasonally Dry Tropical Forest
Eastern Cordillera
Lepidaploa
Chrysolaena
Lessingianthus
Vernonieae
Compositae.

Presentation Type: Oral Paper:Papers for Topics
Session: 37
Location: Franklin B/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:15 PM
Number: 37004
Abstract ID:534


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