VII International Rubiaceae and Gentianales Conference

MORRONE, J.J.; FLORENTÍN, J.E.; SALAS, R.M.; ARANA, M.D.; PRADO, D.E.

Copenhagen

Conferencia; VII International Rubiaceae and Gentianales Conference; 2017

Natural History Museum of Denmark - Botanica

Galianthe is exclusive to the Neotropical region and consists of 50 species divided into two subgenera: Galianthe, with 39 South American species, and Ebelia with 11 species in Mesoamerica and South America. The aims were to establish the distribution patterns of Galianthe species by track analysis, and to evaluate their current distribution based on the available tectonic information and the biogeographical regionalization of the Neotropical region. A total of (±)1400 geographical records of 53 species from 57 herbaria were analysed, representing 100% of the species assigned to Galianthe. Individual tracks were obtained for each species by plotting localities and connecting them by minimum-spanning trees. Generalized tracks and nodes were determined from the spatial overlap among individual tracks. Individual and generalized tracks, and nodes were geographically located using DIVAGIS. Generalized tracks and nodes were superimposed on two maps, one of them with the biogeographical provinces of the Neotropical region, and the other with the distribution of Neotropical seasonally dry forests. Five generalized tracks and four nodes were identified, all located within the Brazilian and Chacoan subregions. These nodes coincide with almost all fragments of Neotropical seasonally dry forests. The origin of the Spermacoce clade, where Galianthe belongs, was dated for the Miocene. The early dispersal of the species, along with the several vicariant events such as the rise of the Andes, the cooling and aridification during the Oligocene-Miocene, the formation of the Chacoan subregion, and the alluvial dynamicsduring the Pliocene-Holocene favoured the adaptive radiation of Galianthe species. In the same way, the intimate coincidence of the ancestral biota of Galianthe with the fragments of Neotropical seasonally dry forests allow us to hypothesize that those remnants of forests could serve as refugia during unfavourable geologic periods, and hence, influencing actively in the current distribution of their species.