Systematics Section / ASPT
Struwe, Lena , Kinkade, Matthew , Pohlit, Adrian M. .
Systematics of Tachia (Gentianaceae): speciation patterns in the Amazon Basin using GIS and phylogenetic data from morphology and DNA.
The genus Tachia (Gentianaceae, tribe Helieae) contains about a dozen species and occurs in wet, forested areas of tropical South America. It is genus of understory shrubs to small trees with axillary flowers. Its closest relative is the genus Macrocarpaea, a montane group with strikingly different morphology. One species is commonly used as an herbal remedy in Brazil to treat malaria. Tachia guianensis is the species most frequently cited in ethnobotanical and pharmacological reports, however, T. grandiflora is frequently misidentified as T. guianensis. The taxonomy in the genus has been confusing and our work has identified new species as well as recircumscribed several others. As part of this revision a trilingual color field guide with descriptions, keys, photos, maps, and illustrations will be made available on-line. Phylogenetic relationships were evaluated based on morphology and sequencing of 5S-NTS and ITS sequences with subsequent parsimony analysis. Detailed locality data for herbarium specimens were used for GIS analysis using the Americas Basemap and the software ArcGIS, to evaluate correlations between species distributions and environmental variables such as elevation, soil type, vegetation, rainfall and other abiotic factors. Several species are specific to white-sand savanna vegetation (Amazon caatinga), which has been considered a more ancient vegetation type than terra firme forests. Biogeographic relationships are evaluated based on phylogenetic patterns, GIS analysis, and geologic and geomorphologic history in tropical South America.
Gentian Research Network
1 - Rutgers University, Ecology, Evolution, & Natural Resources, 14 College Farm Rd, New Brunswick, New Jersey, 08901, USA
2 - Rutgers University, Plant Biology and Pathology, Foran Hall, 59 Dudley Road, New Brunswick, New Jersey, 08901, USA
3 - Instituto Nacional de Pesquisas da Amazônia-INPA, Coordenação de Pesquisas em Produtos Naturais-CPPN, Avenida André Araújo, 2936, Bairro, Petrópolis,, Manaus, Amazonas, 69083 000, BRAZIL
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 1:30 PM