Abstract Detail

Biogeography

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

Radiation of Neotropical Vernonieae (Compositae) from two geographically separate areas of origin.

The Vernonieae is one of the most widely distributed tribes of Compositae with >500 species ranging from Brazil, the New World site of tribal origin, to northeastern North America where the most derived taxa are found. The molecular phylogeny of Keeley et al. (2007) suggested that two widespread genera, Critoniopsis (including Eremosis) and Vernonanthura, could provide insight into the evolution and radiation of the tribe in the Americas. Both genera range from Brazil to northern Mexico and each has > 60 species. Critoniopsis/Eremosis grows at high elevations (2700-3200 m) in the Andes and in the three major Mexican mountain ranges, the Trans-Volcanica, Sierra Madre Occidental and Sierra Madre Oriental. Vernonanthura (a segregate of Vernonia s.l.), on the other hand, is found at low to mid-elevations in savannahs and shrublands (700-1500 m). It was presumed that both genera would show a northward geographic progression from Brazil in accord with the temporal sequence of newly evolved habitats created by the final uplift of the Andes, the closing of the Isthmus of Panama and other climatic events during the past 5 My. However, the phylogeny generated here using chloroplast (trnL, ndhF, matK) and nuclear (ITS) DNA sequences for 140 taxa indicated that despite similar habitats and modern distributions these genera have distinct evolutionary and biogeographic histories. Critoniopsis is distinct from Eremosis and strictly South American, arising in Brazil and speciating in the Andes. In contrast, Eremosis originated in Mexico and has not moved south; There is no overlap in their ranges. Vernonanthura and Vernonia s.l., also originated in different places. Vernonanthura originated in continental Mexico (Chiapas area) near the site of origin of Eremosis, and moved from there southward to Brazil, whereas Vernonia s.l. originated in Brazil and radiated northward to Mexico. Unexpectedly, Eremosis and Vernonanthura from Mexico are older than their South American counterparts. Climatic and geological factors, along with the historical availability of contiguous habitats correlate with the radiation of these genera.

Broader Impacts:

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

Keywords:
biogeography
Brazil
Andes
West Indies
Climate Change
SDTF
Americas
Neotropical.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PBG007
Abstract ID:920
Candidate for Awards:None